Ta b l e o f C o n t e n t s
Volume 46 - Nº1 - June 2009
4
Editorial
The seismic change
Ziad Noujeim
7
Meet the New Associate Editors
Maria Saadeh, Amine El-Zoghbi and Jihad Fak houri
9
Implant Dentistry
Short implants in deficient posterior jaws: current knowledge.
Peter Tawil, Georges Tawil
19
Oral Medicine Research
Host salivary antimicrobial peptides and oral candidiasis.
Mary Ann Jabra-Rizk
25
Laser Dentistry
Erbium:YAG Laser in everyday periodontal practice.
Zahi Badran, Céline Bories, Assem Soueidan
33
Adhesive Dentistry Research
Effect of different surface treatments on bond strength and failure type of zirconium oxide ceramic:
an in-vitro study.
Ziad Salameh, Joseph Hobeiche, Hani Ounsi, Moustafa Aboushelib
37
Craniomandibular Disorders
Temporomandibular disorders (TMDs): a note from the field.
Nabil Tabbara
43
Esthetic Dentistry
Porcelain veneers as an esthetic restorative strategy for the treatment of stained anterior teeth: a
clinical report.
Karim Corbani
47
Removable Prosthodontics
You do not have to be an FBI agent to find and register the retruded contact position in the treatment
of the prosthodontic patient.
Tony Daher, Joseph J. Massad
57
Restorative Dentistry
The used of low intensity laser after cavity preparation in vital tooth: a clinical report.
Carlos de Paula Eduardo, Rodney Garcia Rocha, Karen Müller Ramalho
61
Forthcoming Dental Meetings, Exhibitions and Conventions.
Cited in the WHO Eastern
Mediterranean Index Medicus
The LDA is a regular member of the FDI
ISSN 1810-9632
ISSN 1810-9632
Editor-in-Chief
Fadl Khaled, BDS , DES Endo
Ziad E.F. Noujeim, Dr. Chir. Dent., CES Odont.
Chir., Dipl. Oral Med., Dipl. Cell Therapy, FICD,
FACOMS, FIAOMS
Clinical Instructor,
Department of Restorative Dentistry,
Beirut Arab University Faculty of Dentistry,
Chief of Clinical Services,
Department of Endodontics,
Lebanese University School of Dentistry,
Beirut, Lebanon
[email protected]
Chairperson, Department of Research and Senior Lecturer,
Departments of Oral and Maxillofacial Surgery, Oral Pathology
and Diagnosis, and Basic Science,
Director, Oral Pathology and Diagnosis Graduate Diploma,
Lebanese University School of Dentistry, Beirut, Lebanon
[email protected]
[email protected]
Editors Emeriti
Associate Editors
Ziad Salameh, Dr. Chir. Dent., DES Prostho,
M.Sc., Ph.D., FICD
Assistant Professor, Department of Research, Lebanese
University School of Dentistry, Beirut, Lebanon,
Assistant Professor, Department of Research, King Saud
University College of Dentistry, Riyadh, KSA
[email protected]
[email protected]
[email protected]
Maria E. Saadeh, BDS, MS (Human Morphology),
Residency Ortho. (AUB)
Clinical Associate, Division of Orthodontics and Dentofacial
Orthopedics, American University of Beirut Medical Center,
Clinical Instructor, Department of Orthodontics, Lebanese
University School of Dentistry, Beirut, Lebanon
[email protected]
[email protected]
Jihad M. Fakhouri, Dr. Chir. Dent., CES Odont.
Chir., CES Perio., CES Prostho., DU Implant, DU
Forensic Dent., Dr. Univ. (USJ), MSLP
Assistant Professor, Department of Removable Prosthodontics,
Saint-Joseph University Faculty of Dental Medicine, Beirut,
Lebanon,
Associate Editor, ACES (Dental Journal of Saint-Joseph
University, Beirut),
[email protected]
[email protected]
Amin El-Zoghbi, Dr. Chir. Dent., DU
Occlusodont., DEA, MEACMD, MCNO
Senior Lecturer, Department of Prosthodontics and Occlusion,
and Director, Occlusion Graduate Diploma, Saint-Joseph
University Faculty of Dental Medicine, Beirut, Lebanon,
Associate Editor, International Journal of Stomatology and
Occlusion Medicine,
[email protected]
[email protected]
Nadim Baba, DMD, MSD, FICD, FACP
Philippe Aramouni, DCD, DEA, CAGS,
M.Sc.D.,FICD
Hani Ounsi, DCD, DES Endo., MS (Dent. Mat.),
MS (Biol.Sc.)
Michel Salameh, DCD, CES Pediat. Dent., MIADP,
MIADH, MSFOP
Antoine Cassia, DCD, CES Odont. Chir.,
DU Max. Fac. Prostho., DSO
Levon Naltchayan, DCD, CES Prostho
Pierre Riscalla, DCD
English Reviewer
Tala Sabbagh Yaghi, BA (Transl./Interpret.)
[email protected]
Biostatistics and Epidemiology Consultant
Nada E. El-Osta, DCD, DES Prostho. ,
MS (Bi ol . Med. S c. ), DIU Bi ostat. , DU Forensi c
Medi ci ne
Consultant in Biostatitics / Epidemiology,
St. Joseph University Faculties of Medicine and Dental
Medicine, Beirut, Lebanon
[email protected]
[email protected]
IT Assistant / JLDA Website Manager
Fady Kayyali
Advertising and Marketing
Carole Chaccour Kassouf
The Journal of the Lebanese Dental Association is the official organ of the Lebanese Dental Association.
Statements and opinions in the papers and communications herein are those of the author(s) and not necessarily those of the Editorial Board. The
Editor(s) disclaim any responsibilities or liability for such material and do not guarantee, warrant, or endorse any product advertised in this
publication, nor do they guarantee any claim made by the manufacturer of such product or service.
Address: The Lebanese Dental Association,Victoria Tower, 2nd floor, Corniche du Fleuve, Beirut, Lebanon
Tel. / Fax: 961-1- 611222, www.LDA.org.lb .
Layout and Printing: Metni Printing Press 961.1.283631 Beirut, Lebanon.
Editorial Consultants
George Tawil, Dr. Chir. Dent., DDS, CES
Odont.Chir., CES Perio., Dr.Sc.Odont., FICD,
FACD
Professor of Periodontology, Saint-Joseph University Faculty of
Dental Medicine, Beirut, Lebanon,
Editorial Consultant, International Journal of Oral and
Maxillofacial Implants, Clinical Oral Implant Research,
[email protected]
Zeina A.K. Majzoub, Dr. Chir. Dent., DMD, Dott.
Odont., CAGS, M.Sc.D
Former Professor of Periodontology and Research, University of
Padova, Institute of Clinical Dentistry, Padova, Italy,
Professor of Periodontology and Research and former
Chairperson, Department of Research, Lebanese University
School of Dentistry, Beirut, Lebanon
[email protected]
Sukumaran Anil, BDS, MDS, Ph.D., FICD, FPFA
Charles Sfeir, Dr. Chir. Dent., Ph.D
Professor and Consultant, Division of Periodontics, King Saud
University College of Dentistry, Riyadh, KSA,
[email protected]
[email protected]
Assem Soueidan, Dr. Chir. Dent., CES Perio.,
Dr.Univ. (Nantes), HDR (Nantes), PU, PH
Hani Ounsi, DCD, DES Endo., MS (Dental Mat.),
MS (Biol.Med.Sc.), DEA (Oral Biol.), FICD,
MRACDS (Special Endo. stream)
Director, Center for Craniofacial Regeneration and Professor,
Department of Oral Biology, University of Pittsburgh, School of
Dental Medicine, Pittsburgh, USA,
[email protected]
Professor and Chairperson, Department of Periodontology,
Nantes University, Faculty of Dental Surgery, Nantes, France,
[email protected]
Hani Adbul Salam, B.Sc., BDS, M.Sc., Ph.D
Adjunct Professor and Director of Continuing Dental Education
for the Middle East and North Africa, McGill University Faculty
of Dentistry, Montreal, Canada,
[email protected]
[email protected]
[email protected]
Marcel Noujeim, BDS, DU Oral Biol., DU Oral
Radiol., MS, Diplomate, AB Oral Max. Fac.
Radiology
Assistant Professor, Department of Diagnostic Science, and
Director, Graduate Program of Oral and Maxillofacial Radiology
and Imaging, University of Texas, Health Science Center at San
Antonio, Texas, USA,
[email protected]
[email protected]
Ghassan Yared, DCD, DSO, FRCD (Can.),
MRCDSO
Former Associate Professor, Department of Endodontics, and
former Director of Endodontics undergraduate program,
University of Toronto, Faculty of Dentistry, Toronto, Canada,
[email protected]
[email protected]
Karine Feghali, BDS, DU Perio., Ph.D
Research Fellow, Section of Periodontology, Department of Hard
Tissue Engineering, Graduate School, Tokyo Medical and Dental
University, Tokyo, Japan,
[email protected]
Tony Daher, DCD, CES Prostho., M.Sc. (Educ.),
Diplomate AB Prosth., FACP, FICP
Associate Professor, Department of Restorative Dentistry, Loma
Linda University School of Dentistry, Loma Linda, California, USA,
[email protected]
Part-time Faculty, Kuwait University Health Sciences Center /
Faculty of Dentistry, Department of Restorative Sciences,
Kuwait,
[email protected]
Dina Debaybo, Dr. Chir. Dent., CAGS, M.Sc.D.,
Diplomate, AB Pediat. Dent
Associate Professor and Dental Director, Boston University
Institute for Dental Research and Education, Dubai Healthcare
City, Dubai, UAE,
[email protected]
[email protected]
Nadim Baba, DMD, MSD, FICD, FACP
Associate Professor, Department of Restorative Dentistry, Loma
Linda University School of Dentistry, Loma Linda, California,
USA,
[email protected]
Mary Ann Jabra-Rizk, BS, Ph.D
Associate Professor, Department of Oncology and Diagnostic
Sciences, University of Maryland Dental School, Baltimore,
Maryland, USA,
[email protected]
Arlette Oueiss, BDS, CES Ortho., DU Ortho., MS
(Stat./Epidemiol.), Dr. Univ. (Toulouse)
Assistant Professor, Department of Orthodontics and Dentofacial
Orthopedics, Paul Sabatier University, Faculty of Dental Surgery,
Toulouse, France,
[email protected]
[email protected]
Antoine Cassia, DCD, CES Odont. Chir., DU Max.
Fac. Prostho., DSO
Professor and Chairperson, Department of Oral Pathology and
Diagnosis, Lebanese University School of Dentistry,
Beirut, Lebanon,
Nabil Tabbara, DMD, FAAFO, FAACP
Adjunct Clinical Professor, University of Western Ontario,
Schulich School of Medicine and Dentistry, London, Ontario,
Canada,
[email protected]
Journal of the Lebanese Dental Association
3
Ziad Noujeim, Oral Surgeon and Dental Educator
The seismic change …
The spectacular scientific and technological advances of the past three decades are still capturing the attention
and imagination of the international scientific community, the private sector, the lay public and “first world”
political decision makers : these advances have offered dental science and clinical dental medicine an unprecedented
opportunity to further dental clinical practice and revolutionize dental profession. The challenge of transferring new
research findings to the public is now behind us and insightful scientists have already established the feasibility of
forging an international Agenda for Dental, Oral and Craniofacial (basic and clinical) research.
In Near East and Middle East regions, Lebanon is following and implementing all breakthroughs in medical and
dental biomedical sciences: innovative and disruptive new technologies are now debated and taught in its university
– affiliated hospitals and three dental schools, and almost all lebanese dentists are able to learn the most recent
advancements and cutting-edge solutions.
Far from being a naive optimistic, I constantly fight and challenge pessimism with goodwill, candor, knowledge
and realism. I perfectly acknowledge where my country stands regarding the importance of dental research, but I
also believe in the creative and legendary lebanese spirit that already applies the so-called “biologically grounded
approach to oral health care”. Indeed, and for decades, the 3Rs of dental practice (Repair, Restoration and
Replacement) were implemented, using different types of metal (amalgam, gold), ceramics, plastics (acrylics) and
rubber (for dentures): these non-biological materials are now less used thanks to minimum intervention –MItechniques and patients’ empowerment through awareness, information and motivation. Nowadays, and more than
ever, Lebanese dental practitioners believe in the paramount importance of minimally invasive dentistry which
focuses on almost all dental disciplines, including caries-related dentistry. Lebanon is becoming a leader in
atraumatic restorative treatment -ART- and in comparison to patients that received traditional restorative treatment
(using high-speed drilling), our patients treated with ART proved to be less fearful and anxious and more
cooperative than others. This millenium is one of periodontal medicine, and this recent amazing “discipline” taught
us that preventing or treating a periodontal infection will reduce the risk of cardiac disease, stroke, premature birth,
though we still need further studies and data to confirm these relationships and to establish whether they are really
causal or not. Dentists are now crucial players in overall health care delivery process, true primary health care
professionals, I would say.
On the other side of dental platform, we are looking forward to witness a time when diseased temporomandibular joints, teeth, maxillae, and mandibles won’t be anymore replaced by artificial means (such as titanium
implants), but can rather be regenerated, using stem cells and bioengineering.
Moreover, dental scientists are extensively working on saliva in order to use it as a diagnostic tool, and apart the
advantage of the non-invasive nature of collecting it, salivary antibodies are now measured to detect oral infections,
monitor Sjögren’s syndrome and alcohol abuse, determine clinical and biological response to therapy in breast
cancer treatment, and even assess clinical progression of Alzheimer disease.
4
Journal of the Lebanese Dental Association
Volume 46 - Nº 1 - 2009
A Finnish multidisciplinary team also reported a stunning discovery suggesting that tooth agenesis may be used
as an indicator of susceptibility for colorectal cancer.
Facing this rapidly changing world, the Lebanese Dental Association -LDA- is maintaining core values that
revolve around medically and biologically endorsed dental education, diversity and community care. EvidenceBased Dentistry-EBD-is now mainstream, having been claimed and sustained by a public demand for it to be so,
and it is time for us now to share contemporary knowledge for the only purpose of giving benefit to patients we
serve.
It is now proven that strong evidence is of utmost importance for adoption of innovation. Systematic reviews,
published in high-impact factor peer-review journals and periodicals, are the only means to identify studies with
low-bias, and only explicit and systematic methods designed to limit bias and chance effects should be considered,
and ultimately, more precise effects of healthcare studies and trials are provided through statistically combined
results, using META analysis.
LDA remains committed to excellence and innovation and wholly dedicated to fostering continuing dental
education (through JLDA, seminars, workshops, and conventions), clinical research and patient care with current
and emerging technologies.
Global health care, including oral health care, is now redefined and dominated by information technology sharing
and many of daunting health care challenges affecting people in Arab countries and across the globe must be firmly
met by a community of dental and medical scientists who are willing to act collaboratively and across geographic
boundaries.
A number of indicators point out to the increasing globalization of dental schools and teaching centers in
Lebanon. In the past ten years, dozens of faculty members, clinicians and gifted scientists from the Arab world
(especially Egypt, Saudi Arabia and Jordan), Europe, Australia and North America have been invited to speak at
Saint-Joseph University, Lebanese University, American University Medical Center (in Beirut) and Beirut Arab
University, and most of these prestigious academic institutions are now being involved in active collaborative
research projects, with constantly growing partnerships, and their projects include orthodontics, dentofacial
orthopedics, dental materials, oral pathology and medicine, pain, dental osseointegrated implants,
temporomandibular disorders, esthetic dentistry, oral radiology and imaging, forensic dentistry and endodontology.
Lebanese dental investigators, in Lebanon and abroad, were invited to publish in the present JLDA issue and
forthcoming ones, in order to strengthen links and gather efforts. It is now time to set new international standards
for domestic practice, and in 2009, each dental practitioner has to follow safe, efficient, predictable and evidencebased methods, and there is no reason for lebanese clinicians not to settle with less than the best standard of dental
and oral health care.
In a world where commercial and marketing interests were rampant, dentistry established itself as a profession
and we have lately moved in Lebanon from training to education, making it more respectable, recognized and
honorable, given our enormously increased responsibility towards humanity.
During the 1990s, the LDA became a significant national and pan-Arab player in identifying, debating and
articulating positions on issues important in dental profession and one of LDA’s most crucial purposes remains to
provide opportunity for bringing senior Lebanese dental investigators into intimate contact with our domestic
practitioners and by establishing this informal contact, LDA is making a broadened and deeper understanding
Volume 46 - Nº 1 - 2009
5
happening between lebanese general dental practitioners, thirsty for further knowledge, and lebanese teachers and
scientists who stand now as “vectors of change”.
In this regard, I would like to pay tribute to Professors Nadim Baba and Philippe Aramouni, former Editors-inChief of JLDA, who made drastic changes in our journal’s format and content and strived to maintain a decent, nonbiased critical review, and our long-term goal is to make JLDA one of the most highly esteemed dental journals
that publish clinically relevant and scientifically- based manuscripts.
This is my first issue as editor of JLDA and I am perfectly aware that editorial work requires effort, critical
thinking, attention, integrity, ethics, hard work, knowledge, humility, and given that all these attributes are rarely
found in one person, team effort is inevitable. Dentistry is becoming complex, this field being assembled by so many
disciplines and specialties that make dental picture complicated, and if our journal aimed earlier to enhance clinical
skills and abilities only by publishing short clinical notes and case reports, we are doing our best now to emphasize
contemporary and useful clinical procedures, educational cases and research, as we look forward to embodying what
we believe to be the seismic change that lately occurred in “dental minds”.
As of now, our journal will be designed to address practical issues that mainly concern general practitioners,
providing reliable and authoritative clinical basis for different treatment modalities. We will tackle, as well, research
issues and developing innovations authored by lebanese, arab and foreign scientists and clinicians.
It is the right and duty of dentists to get state-of-the-art information and judge, for themselves, which diagnostic
and treatment concepts lead to reliable long-term results and which do not. Commercialism in Dentistry is rising:
periodontology, as science and practice, is slowly vanishing, dentists are constantly pushing implants, whitening,
and not nicotine patches, and most of them extract asymptomatic third molars and weigh only what works in their
office, regardless of what academic researchers are saying. Before this ethical issue, the LDA is striving to raise
scientific controversies, foster intelligent discussions, support and endorse a common ethical set of values, in order
to save our patients from commercialism.
This millenium is the era of molecular approaches to oral therapeutics, newest technologies are already
integrated in routine clinical practice, but there is still a number of significant challenges to be overcome in the
development of truly innovative products in dentistry.
As a practicing dentist and dental educator, I feel particularly happy and lucky to witness changes that brought
to our hands cone beam volumetric tomography, CAD-CAM technology, bonded-zirconia restorations, saliva-based
diagnostics, novel therapies and preventive agents for dental caries, biomimetic materials for regenerating tooth and
jawbones, porcelain laminate veneers, Laser dentistry, ultrasonic tips, surgical operating microscope, orthodontic
mini-screws and many technologies to come!
In the blossoming world of cosmetic dentistry, teeth whitening and smile makeover reign supreme, but behind
this facade, there are other worrying and critical dental and oral health problems waiting to be solved by “oral
physicians”. Finally, as a dental community, we constantly need to be provided with scientific rationale and
evidence-base for new technologies in order to best implement new advances and ensure their ultimate success.
Ziad Noujeim
Editor-in-Chief, JLDA,
Chairperson, Department of Research,
Senior Lecturer, Departments of Oral and Maxillofacial Surgery,
Oral Pathology and Diagnosis, and Basic Science,
Director, Oral Pathology and Diagnosis Graduate Diploma,
Lebanese University School of Dentistry, Beirut.
6
Volume 46 - Nº 1 - 2009
Meet the New
Associate Editors
Maria Saadeh graduated with a BDS
degree from Lebanese University School of
Dentistry in Beirut. She completed her
postgraduate residency in orthodontics at the
American University of Beirut Medical Center
(AUBMC), followed by an additional year as
chief resident. In 2008, she earned a Masters
of Science degree in Human Morphology
(AUB’s Faculty of Medicine) and she is
currently enrolled in a Masters in Public
Health program (AUB’s Faculty of Health
Sciences).
Dr. Saadeh was appointed as Clinical
Instructor in the Department of Orthodontics
at Lebanese University School of Dentistry in
November 2006 and as Clinical Associate in
the Division of Orthodontics and Dentofacial
Amine El- Zoghbi is Director of Occlusion
Graduate Diploma and Senior Lecturer in the
Department of Prosthodontics and Occlusion
at Saint-Joseph University Faculty of Dental
Medicine, in Beirut. He is also one of the
Associate Editors of the International Journal
of Stomatology and Occlusion Medicine, a
recent European periodical devoted to
occlusion medicine, masticatory system, oral
rehabilitation and interdisciplinary dentistry.
Dr. Zoghbi received his dental degree (Dr.
Chir. Dent.) from Saint-Joseph University in
Journal of the Lebanese Dental Association
Volume 46 - Nº 1 - 2009
Orthopedics at AUBMC in
July 2008. She is involved
in the treatment of patients
in private and academic
settings, as well as didactic
and clinical teaching of
orthodontic residents.
Her research projects
target the effect of cancer therapy on dental
and skeletal maturity in children. Her
scholarly contributions include scientific
publications, posters and oral presentations at
national and international conventions on
various topics including her main research
interest, as well as evidence-based practice in
dentistry and orthodontics.
Beirut and completed a
postgraduate training in
occlusion at University of
Aix-Marseille II Faculty of
Dental
Surgery,
in
Marseille,
France,
graduating with a diploma
(DU) in occlusodontology. He maintains a
private practice (in Beirut) covering all
aspects of restorative dentistry, with a focus
on occlusion and temporomandibular
disorders.
7
Meet the New Associate Editors
Jihad Fakhouri is a graduate of Saint-
for
10
years
Joseph University Faculty of Dental Medicine
Department
in
Prosthodontics
Beirut,
Lebanon.
He
completed
a
at
the
Nord”
in
“Hôpital
Lyon
Marseille, France.
certificates
(CES)
attaining
in
advanced
prosthodontics,
the
of
postgraduate training in Paris, Marseille and
(France),
in
Currently, Dr. Fakhouri
He
is Assistant Professor in the Department of
graduated in implant dentistry from the
Removable Prosthodontics at Saint-Joseph
Institute of Stomatology and Maxillofacial
University Faculty of Dental Medicine, in
Surgery of University of Paris VI and earned
Beirut. He is also Associate Editor of the
graduate
dental journal of Saint-Joseph Dental Faculty
periodontology
and
diplomas
oral
(DU)
surgery.
in
removable
prosthodontics, anthropology and forensic
(ACES)
dentistry. He also earned a Masters degree in
Dentaires” journal in Marseille. He is the
Medical and Biological Sciences and an
author and co-author of more than 14
advanced studies diploma (DEA) in Health
scientific papers. His main interests are
Ecomonics. Lately, he attended a doctoral
impression materials and techniques, implant-
course and undertook an original research at
supported
Saint-Joseph
a
prosthesis. He maintains a private practice in
“Doctorat d’Université” in Oral Biology and
Beirut, Lebanon and has lectured in Lebanon,
Biomaterials.
France, Syria and Germany.
University
leading
to
in
Beirut
and
of
overdentures
“Industries
and
partial
During his specialty training, he worked as
Lecturer, Clinical Associate and Researcher
8
Volume 46 - Nº 1 - 2009
Implant Dentistry
Short implants in deficient posterior jaws: current knowledge.
Peter Tawil1, Dr. Chir. Dent. , Georges Tawil2, Dr. Chi r. Dent. , Dr. S c. Odont. , FICD, FACD
A bst ract
In clinical situations where bone is severely resorbed and implant-supported prostheses indicated, the strategy may be oriented
either towards reconstructive surgery and placement of implants in regenerated bone volume and height or use of short implants.
Improvements in surgical technique, surface texture and geometry of components as well as a better understanding of the
biomechanics of short implants increased their reliability. Despite unfavorable prosthetic parameters, long-term results in cases
of good bone density, good control of occlusion and parafunctions are equal to longer implants.
The long-term survival of endosseous implants is a
phenomenon dependent on multiple biological and
functional factors1. It has been shown that implant
length, diameter, location (mandible v/s maxilla)and
surface characteristics, bone quality, parafunctions,
prosthetic parameters and biomechanical load are the
main factors that can affect the success rate. Whereas
bone quality and quantity seem to be among the most
influential parameters affecting the outcome of
therapy2, implant length variation was generally
associated with a greater failure risk. In studies
comparing survival rates of short implants, mostly
machined-surface, with longer implants, failures were
more often observed on implants of short length3,4,5,6,7,8,9
placed in maxillary sites where bone is generally of
lesser density and the functional load remarkably
increased10. Failure rates varied between 2.5% and
25%3,9,11. A second group of authors, although
concluding that failure rates are higher with short
implants, still showed adequate survival rates11,12,13. A
third group of authors reported that implant length did
not appear to significantly influence the survival
rate14,15,16,17,18,19,20,21. Finally, a fourth group which focused
specifically on short implants, showed similar clinical
1 Postdoctoral Periodontics, University of Pennsylvania,
School of Dental Medicine, Philadelphia, USA,
2 Professor of Periodontology, Saint-Joseph University
Faculty of Dental Medicine, Beirut, Lebanon.
Journal of the Lebanese Dental Association
Volume 46 - Nº 1 - 2009
outcomes to those reported in longer implants with
survival rates ranging between 88%-100%22,23,24,25
26,27,28,29,30,31,32
. Why are success rates of short implants
today comparable to longer implants? What has
changed? What are the factors at stake in the
improvement of therapeutic outcomes? And are short
implants a viable solution in situations of atrophic
alveolar bone, especially in posterior mandible and
maxilla?
1. Implant length and diameter: Choices based on
biology.
There was a general belief that a long implant
would offer a greater resistance to occlusal load, a
higher survival rate and a more secure option
compared to a short implant, in case of peri-implant
bone loss. In a long-term study on the effectiveness of
oral implants in the treatment of partial edentulism33,
85% of implants had a diameter of 4.1mm and only
2.7% a diameter of 4.8mm. Implant length varied
between 8mm and 14mm. The overall success rate
reported was 96.7% after 7 years, with no difference
among implants of different length and diameter.
Other reports3,4,5 using implants of different surfaces
and a conventional surgical protocol reported lower
success with short implants. It is difficult, based on the
absence of comparative long-term prospective clinical
trials on implant length in posterior jaws, to draw
definitive conclusions on influence of implant length
9
Tawi l P, Tawi l G
on clinical therapeutic outcome (Fig.1). In most
reported clinical studies, implant length reflected the
state of jaw resorption. Longer implants were used
where bone height was more available. However,
when comparing different studies where implants of
different lengths were used in partially edentulous
posterior jaws, it seems today, that implant surface,
bone quality, jaw resorption and practitioner’s learning
curve influence better the success rate than implant
length32.
Finite element analysis, although not reproducing
with great precision the conditions in-vivo, allowed us
to better understand biomechanical aspects of short
implants. Pierrinard34 demonstrated that bone stress
concentrates in the marginal area, irrespective of
implant length. Implant displacement increases as
length decreases, with a small difference at implant
neck level and a greater difference at apical level.
Bicortical anchorage reduces displacement(-5.8%) for
implants of same length but increases stress
concentration. Stress concentrations are confined at
the first thread. Difference is remarkable between 12
mm and 6 mm implants when it comes to micromotion
(-88%). Greater displacement of short implants in
bone and more bone flexing may reduce the risk of
biomechanical complications. In case of overload,
short implants may ultimately fail while longer
implants display mechanical complications.
According to Himmlova35, an increase in implant
diameter decreases the maximum von Mises
equivalent stress around implant neck more than the
implant length (31.5% decrease in stress from 3.6mm
to 4.2 mm diameter). In the same context, wider
implants rather than longer implants decrease stress
level34,36. However, no relationship could be found
between marginal bone loss and implant diameter in
most studies, while low changes in crestal bone levels
were reported.
The choice of implant length depends ultimately on
long-term results. Prospective clinical studies, where
all biological and biomechanical factors are accounted
for, will define indications and limitations of treatment
approaches.
2. Implant surface: What has changed?
Among 12 published studies indicating that short
10
Fig.1. Short implants placed in sites where longer implants
can be placed .
implants failed more often than longer ones, 11 used
machined-surface implants3,4,5,7,9,11,13. Change in the
implant surface has led to consistently better results.
Khang and co-workers19 compared machined and
double acid-etched implants. Double acid-etched
implants provided better outcomes than machinedsurface implants (95% v/s 86.7% success rate).
Feldman and co-workers37 compared the survival rate
of short to long machined-surface v/s dual acid-etched
(DAE) implants. There was no statistical difference
between short and long DAE implants (0.7%), while a
difference of 7.1% in posterior maxilla was found
between machined-surface implants of different
lengths. In a systematic review, Hagi and co-workers38
compared the surface (machined v/s sintered porous
v/s textured),the macrogeometry (threaded v/s non
threaded or porous) and the length of implants (>7 mm
v/s <7 mm) concluding that surface characteristics
clearly play a major role in the success of short
implants and compensates for shorter implant length.
Deporter25 demonstrated a 100% clinical success rate
with sintered porous surface implants. The addition of
a roughened surface to the machined threads increases
bone to implant contact, interlocking and
osseointegration, and therefore improves the overall
clinical performance of short implants38,39. In a metaanalysis on the effect of implant length on survival of
short rough-surfaced implants, it was concluded that
no significant difference in survival rate could be
found between short (<8 mm) and conventional (>10
mm) rough-surfaced implants either in partially or
totally edentulous patients40, underlying again the
Volume 46 - Nº 1 - 2009
Tawi l P, Tawi l G
importance of implant surface in the outcome of
therapy.
Likewise, Bernard and co-workers41, in a study on
dogs, compared the reverse torque on implants with
machined surfaces (Bränemark) and those with
roughened surfaces (ITI). Reverse torque was 104-192
N/cm for 6-10 mm ITI implants, and 61-69 N/cm for
7-10 mm Bränemark implants.
3. Poor bone quality: What to do?
One of the main challenges in implant placement in
posterior jaws is bone quality. In these sites, bone is
less cortical and more spongious, rendering primary
stability and bone-to-implant contact a difficult task.
Bahat3 advocated a modification of the drilling
sequence in case of poor bone quality.
Underpreparation of implant site, a soft precise
surgical technique, will definitely enhance implant
primary stability31. Countersinking should be
minimized27, and an adapted surgical protocol will
definitely improve osseointegration of short implants.
The use of osteotomes rather than drilling in implant
site preparation was advocated by Summers42 and may
be a good approach for bone condensation, but on the
other hand, it has been reported43 that bone
condensation is also associated with microfractures
and alteration of microcirculation and vascular fluids
flow that may potentially delay healing and diminish
bone to implant contact during the first post-operative
weeks.
4. Splinting short implants to longer ones: A real
solution?
The majority of early studies reporting acceptable
results on short implants used longer implants
concomitantly and preferably splinted short to long
implants, rendering the interpretation of clinical results
and biomechanical analysis of short implants more
difficult. Splinting short implants to longer ones
obviously alters distribution of masticatory loads and
resistance to functional stresses, and increases
anchorage surfaces25,44. As for implant positioning in an
intermediate or distal position (Fig.2), Lekholm50 and
Bahat5 found out that placing a short implant in an
intermediate position was functionally more favorable.
Other authors14,17,20 could not correlate implant failure
Fig. 2. A 7x5 mm Nobel Biocare (NB)* TiU** shorty
implant placed in an intermediate postion in a deficient
subsinus ridge.
with implant length. Nevertheless, it seems that there
is a lack of information and standardization regarding
this subject; clinical outcomes can be misinterpreted
and conclusions incorrect.
5. Splinting short implants together: A better
solution?
Splinting of short adjacent implants was initially
indicated to increase the resistance to functional and
parafunctional load. In a study by Tawil and Younan,28
each missing tooth was replaced with a machinedsurface implant and implants were splinted together
with a 95.5% success rate (Figs. 3a,3b,4,7,8,9): in this
study, bone quality may have been a major factor of
success but it remains difficult to determine the
importance of splinting in clinical outcome in the
absence of a free-standing control group. On the other
hand, in Gentile and co-workers45 study on short Bicon
implants, 97.7% of 6x5.7mm implants used were
restored with single crowns and yet reached a 92.2 %
success rate. In a study by Deporter and co-workers25,
151 Endopore implants were placed in the maxilla,
56% of the prostheses were splinted together while
43% were not. After a mean functional time of 6
months, the cumulative survival rate was 97.3%. No
significant difference was found between splinted and
single crowns. Rokni and co-workers46 found out that
bone loss was less extensive on short porous surfaced
implants restored with single crowns as compared to
splinted implants. A biomechanical explanation to this
phenomenon was that micromovements of short
* NB = Nobel Biocare®
** TiU = TIUNITE® surface
Journal of the Lebanese Dental Association
11
Tawi l P, Tawi l G
Fig. 3a. Reduced subsinus ridge height Fig. 3b. Short implants (7x5 mm and 7x6
but large enough to place a short and mm NB) in terminal position replacing
in a 7mm sub-sinus ridge, splinted to a
wide implant.
#161 and 17 in a in7site mm
sub-sinus ridge,
15
splinted to an 11.5x3.75 mm implant
placed in site 15.
Fig. 4. 7x5 mm implant replacing # 16
splinted to a 10x3.75 mm in position 15.
Two year results.
Fig. 5. A 7x5 mm NB implant in
position 16 replacing a single molar.
Note the C/I ratio and the dimension
of the clinical crown. Three year result.
Fig. 7. A short 8.5x3.75 mm NB TiU
implant 8.5x3.75mm
splinted
to a 10x3.75 mm NB
NB TiU implant splinted to a 10x3.75mm NB TiU)
r
TiU)
replacing # 46. Result at three years.
Fig. 6. 8.5 mm x 4 NB TiU implant
replacing # 47. Four year result.
Fig. 8. Three mandibular implants of Fig. 9. Two 8x5 mm NB machined8.5x3.75 mm, 7x4 mm et 6x5 mm NB surface implants. Result at ten years.
machined surface replacing # 45,46 and
47. Result at eleven years.
12
Fig. 10. Edge-to-edge posterior occlusion
to better distribute forces along the long
implant axis, after elimination of working
and non-working interferences.
Volume 46 - Nº 1 - 2009
Tawi l P, Tawi l G
implants under functional load distributed forces better
if free-standing than splinted and better when short v/s
long. This is in agreement with biomechanical findings
in finite element analysis of Pierrinard and coworkers34. On the other hand, the need for implant
splinting may depend on implant marginal
configuration (external or internal hex, cone Morse or
butt joint)47. Micromovements have been described in
case of external hex connection at the abutmentimplant interface which may cause greater strain on
prosthetic components and microbial microleakage55.
These considerations most likely favor implant
splinting rather than biomechanical factors related to
resistance to functional load by short rough-surfaced
implants.
6. Survival of short implants in mandible
Early studies indicating good long-term results on
short
implants,
independently
of
surface
characteristics and prosthetic considerations, used
preferably the mandible as a primary site versus the
maxilla. Tawil and Younan28 used the mandible in
88.8% of the cases, whereas Deporter and co-workers25
used it in 100% of the cases. The main reason for
indicating short implants in mandible is better
mandibular bone quality compared to maxilla (Fig. 6).
It is also of relevance to note that vertical bone
augmentation techniques in mandible are more
difficult to achieve and less predictable than in maxilla
(lateral approach or osteotome technique sinus lifts).
Numerous reports using short implants of different
surfaces and macrogeometry confirmed the approach
validity in posterior mandible20,29,30.
7. Survival of short implants in maxilla
Few studies29,31,48,49 used exclusively short implants
in maxilla (Fig. 5). Success rates of 94.6% to 100%
were reported. Fuggazzato and co-workers27 placed
979 implants in molar position, restored them with
single crowns and followed them up to 84 months,
with a cumulative success rate of 95.1%. These
success rates may be attributed to the use of rough
surface implants and a better assessment of bone
quality, with a change in surgical technique. A study on
ultra-short implants (5x5 mm)48 with success rates of
85.7% for maxilla and 100% for mandible after a
functional period of 1 to 8 years may push even further
the limits of conservative approaches in implant
dentistry. However, long-term controlled studies and
bigger sample size are warranted to determine the
validity of these results in maxilla.
8. Influence of prosthetic parameters on short
implant survival
Bone resorption is often accompanied by
unfavorable jaw relationship and maxillo-mandibular
space increase, with inevitable prosthetic consequence
of excessive crown height and occlusal table design and
increased bucco-lingual cantilever52. Maximum applied
and tolerated occlusal forces vary greatly according to
implant position on the arch, patient’s functional and
parafunctional habits and nature of opposing dentition.
High bending moments, unfavorable distribution and
intensity of occlusal forces may contribute to
biomechanical overload on hardware and supporting
bone53 (Figs. 10,11,12,13). Biomechanical complications
such as screw loosening and fracture, abutment fracture,
implant fracture or loss of osseointegration can occur.
But, are unfavorable prosthetic parameters really
dreadful on short implants survival?
Few studies in literature addressed this subject. If
in healthy dentition the optimal crown-to-root ratio is
1/2, this is rarely the case in implant-supported
prosthesis due to uncompensated bone loss. Rokni
and co-workers46 evaluated implant length, implant
surface area and crown-to-implant (C/I) ratio in
relation to crestal bone level changes. The mean C/I
ratio in their study was 1.5 (SD*** = 0.4; range 0.8 to
3.0), with 78.9% of implants having a C/I ratio
between 1.1 and 2.0. Neither C/I ratio nor estimated
implant surface area (< 600 mm2 / > 600 mm2)
affected steady-state crestal bone levels. In a study by
Tawil and co-workers54 on 262 implants, relatively
few (C/I) ratios were < 1 or > 2 (16.2%). Occlusal
table (OT) width ranged between 5.4 and 8.3 mm. No
significant difference in peri-implant bone loss was
correlated with C/I ratios or width of occlusal tables.
Neither mesial nor distal cantilevers length (2.75 ±
1.65 mm and 2.24 ± 1.60mm) nor bruxism, nor the
type of occlusion between the opposing jaws had a
significant effect on peri-implant bone loss. Mean
bone loss was 0.74 ± 0.65 mm. If the occlusion is
*** SD = Standard Deviation
Journal of the Lebanese Dental Association
13
Tawi l P, Tawi l G
Fig. 11. Emerging axis of implants in
relation to occlusal table. A greater
cantilever distance will cause more load
on cervical part of the implant.
Fig. 12. Short implants replacing two
mandibular molars. Distal cantilever may
constitute
a
biomechanical
risk.
Occlusion and parafunctions should be
well controlled.
carefully adjusted and occlusal contact closely placed
to the emerging axis of implants, forces will be fairly
distributed, with no major risk of more biomechanical
complications (Figs. 10,11).
Consequences of increased crown to implant ratios,
occlusal table width or cantilevers are therefore
negligible in cases of favorable occlusal loading (Figs.
12,13)
CONCLUDING REMARKS
Improvement of success rates and long-term
survival of shorts implants is possible today due to
changes in implant surface that greatly enhance
osseointegration. Also, with a better assessment of
bone quality and its technical management, a better
control of implant surgical technique32 under
preparation28 and limited countersinking27, better
results are expected. With a greater understanding of
biomechanics of short implants based on finite
elements models in vitro34,36, a proper evaluation of the
prosthetic parameters53,54 and practioner’s learning
curve, higher success rates can be reached. More
investigations and controlled studies are needed before
final conclusions can be drawn.
Fig. 13. Three mandibular short implants
replacing mandibular molars. Note the
mesial cantilever. Occlusion must be
carefully adjusted.
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28- Tawil G , Younan R.Clinical evaluation of short machinedsurface implants followed from 12-92 months. Int J Oral
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the use of short implants: results from a private practice.
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review of study outcomes with short (< or = 7 mm)
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management of the posterior maxilla using short
16
Volume 46 - Nº 1 - 2009
Oral Medicine Research
Host salivary antimicrobial peptides and oral candidiasis.
Mary Ann Jabra-Rizk*, Ph. D
A bst ract
The oral cavity is a primary target for opportunistic infections, particularly oropharyngeal candidiasis. The etiologic agent
Candida albicans is the most pathogenic human fungal species that can either colonize asymptomatically or cause superficial or
even life-threatening infections, particularly in HIV+ and other immunocompromised individuals. However, the reasons behind
this transition from commensal to pathogen and the enhanced susceptibility of HIV+ individuals to oral candidiasis, are not clear.
In the oral cavity, salivary antimicrobial peptides are considered to be an important part of the host innate defense system in the
prevention of microbial colonization. Histatin-5 has specifically exhibited potent activity against C. albicans. Our previous
studies have shown histatin-5 levels to be significantly reduced in the saliva of HIV+ individuals, indicating an important role
for this peptide in keeping C. albicans in its commensal stage. However, the versatility in the pathogenic potential of C.
albicans is the result of its ability to adapt through the regulation of virulence determinants, most notably of which are secreted
proteolytic enzymes involved in tissue degradation and invasion. In this report, we present novel findings demonstrating that C.
albicans secreted proteolytic enzymes efficiently and rapidly degrade and deactivate a host peptide involved in the protection of
the oral mucosa against C. albicans, thereby providing new insights into the factors directing the transition of C. albicans from
commensal to pathogen. The dissemination of such crucial information has important clinical implications for alternative
therapy for the prevention of oral candidiaisis, particularly in susceptible hosts.
The oral cavity is a unique environment and a
primary target for opportunistic infections, particularly
candidiasis caused by the human pathogen Candida
albicans (C. albicans)1-3. This commensal fungus
commonly colonizing human mucosal surfaces, has
long been adapted to the human host and has evolved
because of the specific demands of the host
environment. Distinctively, under conditions of
immune dysfunction such as HIV infection, colonizing
C. albicans strains can become opportunistic
pathogens causing recurrent mucosal infections. The
increasing emergence of strains resistant to the
commonly used antifungal agents has made clinical
management of candidiasis increasingly difficult and
the need for improved drug therapies crucial3, 4.
* Associate Professor, Department of Oncology and
Diagnostic Sciences, University of Maryland Dental
School, Baltimore, and Department of Pathology, School
of Medicine, University of Maryland, Baltimore, USA.
Journal of the Lebanese Dental Association
Volume 46 - Nº 1 - 2009
The oral mucosa constitutes a critical protective
interface between external and internal environments,
serving as a barrier to hundreds of microbial species
present in this environment2, 3. In the oral cavity, saliva,
a complex mix of fluids from salivary glands, plays an
important role in the maintenance of oral mucosal
health5, 6. Specifically, saliva contains a set of
antimicrobial peptides produced by the host and
considered to be an important part of the innate
immune system, contributing to maintaining the
balance between health and disease in this complex
environment7, 8. Surprisingly, the important role of
these natural antimicrobials in the protection of the
oral cavity from constant exposure to microbial
challenges and particularly their potential as
therapeutic agents is only just beginning to be
appreciated.
Most notable among the natural immune salivary
19
Jabra-Rizk MA
antimicrobial peptides are the histatins, a family of
low-molecular-weight, histidine-rich, cationic proteins
produced and secreted by human parotid and
submandibular-sublingual glands9-11. Histatins show
killing activities against numerous oral bacteria, as
well as potent antifungal properties against pathogenic
fungi including C. albicans10, 12, 13. Histatin-5 (Hst-5)
specifically, a 24-amino acid member of the family,
has exhibited the highest level of activity against C.
albicans, including strains resistant to antifungal
agents, implicating a mode of action for this peptide
different than the commonly used drugs14, 15.
Although not substantiated since, studies in the
early 1990s have reported changes in salivary histatin
concentrations in HIV+ individuals, as a result of
salivary gland dysfunction16, 17. Given the important
role of saliva in maintaining oral health, it is
conceivable that alterations in salivary gland secretion
and/or composition are liable to contribute to the
markedly enhanced predisposition of this population
to oral candidiasis. Yet, studies confirming these
important observations have been lacking, most likely
due to the lack of feasible methods for measuring
salivary histatin concentrations. Recently, however, we
confirmed these observations in a study comparing the
levels of salivary Hst-5 between a group of HIV+ and
HIV- individuals at the University of Maryland Dental
School in Baltimore18. Results from the investigation
demonstrated significantly lower Hst-5 levels in HIV+
group, concomitant with increased prevalence of C.
albicans in the oral cavity, highlighting the
involvement of host innate immunity in the protection
against C. albicans colonization18.
In the case of C. albicans, the transition from
harmless commensal to disease-causing pathogen is
finely balanced and attributable to an extensive array
of virulence factors. This is quite obvious through the
diverse manifestations of candidiasis, for in addition to
oral and mucosal infections in the United States of
America, C. albicans is currently ranked the third most
commonly isolated bloodstream pathogen in
hospitalized patients with a mortality rate of 40-50%4,
19, 20
. The versatility in the pathogenic potential of this
fungal species is the result of its ability to adapt,
20
evolve and evade host immune defenses through the
regulation of virulence determinants, selectively
expressed under suitable predisposing conditions21-23.
These virulence factors may well vary, depending on
the type of infection, the stage and site of infection and
the nature of the host response.
Most notable among the pathogenic factors of C.
albicans are the aspartic proteases (Saps), a family of
secreted proteolytic enzymes considered to be vital for
its pathogenesis24-26. Candida albicans Saps have been
shown to degrade a variety of host defense proteins
such as lactoferrin and immunoglobulins27. However,
despite the extensive available information on the
association of C. albicans Saps and host protein
degradation, in-depth investigations into the ability of
the Saps to degrade small salivary antimicrobial
peptides, specifically those with potent anti-candidal
properties such as histatins, has not been fully
investigated. Such findings would carry significant
implications as they may contribute to our
understanding of the quandary of the enhanced
propensity of HIV+ population to oral candidiasis. To
that end, a study was initiated in our laboratory to
analyze the ability of C. albicans to degrade Hst-5 invitro and to attribute the proteolytic activity to the
secreted aspartic proteases. The following is a
summary of the findings from the recently published
work28.
In order to determine whether C. albicans possess
the ability to degrade Hst-5, degradation assays were
designed where following exposure of the peptide to
C. albicans yeast cells for 2 hours at 37°C, the
degradation reactions were subject to sodium dodecyl
sulfate polyacrylamide gel electrophoresis (SDSPAGE) analysis. Images from these experiments
clearly revealed a gradual loss of peptide integrity
proportional to the C. albicans cell density (Fig.1A)
and time of exposure (Fig.1B) demonstrating that C.
albicans cells efficiently and rapidly degrade Hst-5 in
as little as 20 minutes. In contrast, using a range of
Hst-5 concentrations, the level of degradation was
shown to be inversely proportional to Hst-5
concentration (50-200 µg/ml). Combined, these
observations indicated that occurrence of intricate
Volume 46 - Nº 1 - 2009
Jabra-Rizk MA
interactions in the oral cavity involving host and
pathogen factors, may shift the balance in favor of the
host or the pathogen. In the case of individuals with
compromised immune system, the pathogen often
prevails.
It is important to note that adherence of C. albicans
to oral tissue is a pre-requisite for colonization and
proliferation leading to tissue invasion and infection29,
30
. Candida albicans cell concentrations of 1 x 102
cells/ml and below are indicative of commensal
colonization in the oral cavity29. In our experiments,
this cell density was shown to be susceptible and
unable to degrade physiological concentrations of Hst5 in-vitro. However, our results demonstrated that the
level of degradation of Hst-5 was proportional to the
cell density of C. albicans, supporting the hypothesis
that the role Hst-5 plays in the oral cavity is crucial in
controlling the proliferation of commensal C. albicans
strains and consequently, their over-colonization of
oral mucosa.
More importantly, in order to identify the cleavage
sites for C. albicans on Hst-5, peptide mapping was
performed on the degradation fragments using RPHPLC separation followed by MALDI-TOF/TOF MS
analysis. rHPLC separated degradation products into 4
peaks (Fig.2A) and subsequent MALDI analysis
showed them to correspond to Hst-5 fragment 18-24,
1~11, 1-17, and intact Hst-5 (peaks 1 - 5 respectively)
(Fig.2B). More importantly, four of the identified
cleavage sites were located within the 12-amino acid
antimicrobial fragment of Hst-5 implying that
cleavage at these sites would compromise the anticandidal properties of Hst-5.
Consequently, to address the implications of Hst-5
degradation on its killing potency, killing assays were
performed as previously described31. Hst-5 was
evaluated following its degradation by C. albicans
cells, where fragments liberated from degradation
reactions were used in killing assays. Briefly, C.
albicans cells at various cell densities were mixed with
Hst-5 and incubated for 2 hours at 37ºC with shaking.
Aliquots from reactions were inoculated on YPD agar
and incubated for 24-48 hours at 35ºC. Following
incubation, the number of single colonies on each plate
was counted and the percent cell killing calculated
with respect to that obtained from exposure of the
Journal of the Lebanese Dental Association
1A
1B
Fig. 1. Degradation of Hst-5 (A) Degradation by C. albicans
demonstrating degradation level proportional to cell density
(cells/ml) (B) Degradation of Hst-5 over time (minutes)
demonstrating degradation level proportional to exposure
time. Minor degradation following 20 mins incubation at
37ºC observed by the appearance of lower weight product,
whereas significantly increasing level of degradation seen
after 1 hour and 2 hours.
2A
2B
Fig. 2. Peptide mapping of cleaved Hst-5 (A) Separation of
Hst-5 fragments by RP-HPLC following degradation by C.
albicans resulting in 4 peaks corresponding to fragments 1824, 1-12, 1-17, and 1-24 on the Hst-5 amino acid sequence
(B) Comparison of cleavage fragments (1 – 4) identified by
Mass Spectrometry following degradation of Hst-5 with C.
albicans. The boxed fragment in orange represents the part
of peptide with antimicrobial properties. The green bars
represent fragments generated from cleavage within the
antimicrobial fragment.
yeast cells to the intact un-cleaved Hst-5. The results
from these experiments demonstrated that in contrast
to the intact Hst-5, the fragmented Hst-5 had no effect
on C. albicans. In addition, the percentage of killing of
C. albicans by Hst-5 was inversely proportional to the
cell density where Hst-5 was able to kill 90% of the
cells at a density unable to cause any significant level
of degradation (1x106 cells/ml) (Fig.1A). Conversely,
C. albicans cell density shown to degrade Hst-5 (50%)
resulted in 50-60% drop in killing (Fig.1A). More
21
Jabra-Rizk MA
importantly, testing the Hst-5 cleaved fragments
liberated into the supernatants for killing ability
resulted in 0% killing of C. albicans at previously
susceptible cell density. Combined, these findings
demonstrated that the ability of Hst-5 to kill C.
albicans largely depends on its integrity and the ratio
of its concentration to the cell density of C. albicans.
The novel findings from this investigation
demonstrate the ability of C. albicans to efficiently and
rapidly degrade salivary anti-candidal peptide Hst-5
through the secretion of proteolytic enzymes. In turn,
these findings seem to attribute a new function for
these enzymes in the oral cavity, where in addition to
tissue invasion they also target a host substrate
comprising the first line of defense against invading
pathogens. Furthermore, these findings combined with
those from our initial investigations demonstrating
decreased salivary Hst-5 levels in HIV+ individuals,
the most vulnerable population to oral candidiasis,
strongly support the notion of an involvement for Hst5 in the enhanced propensity of HIV+ individuals to
this opportunistic infection18. In summary, this report
provides new insights characterizing a defined
mechanism involving both host and pathogen factors
behind the transition from commensalism to
parasitism, ultimately leads to the development of oral
candidiasis.
ONGOING STUDIES
In light of these recent findings, our laboratory has
initiated an in-depth investigation to validate the
following hypothesis: “Decrease in levels and anticandidal potency of salivary Hst-5 in HIV+
individuals leads to increase in C. albicans
colonization and proliferation and attributes an
important role for the host innate immunity in the
enhanced propensity of these individuals to recurrent
oral candidiasis”. Specifically, using a large HIVinfected and non-infected populations with various
subsets of individuals, we aim to:
1- Determine the salivary Hst-5 levels in patients’
saliva, assess the prevalence of C. albicans in
their oral cavities and determine the level of Hst5 degradation of the isolates recovered from the
patients.
2- Utilize the patients’ saliva with pre-determined
a: PAS = Periodic Acid-Schiff.
b: HE = Hematoxylin and Eosin.
22
Fig. 3. A murine model of sustained oral candidiasis. Mice
are infected with 1x107 C. albicans cells and euthanized 4
days post-infection and tongue was harvested and subject to
histopathological analysis. Following PAS a and H&Eb
staining, both hyphal and blastoconidial forms are seen
invading the superficial epithelial layer of the mucosa and
the invasive hyphae invading parakeratin and spinous layers.
These histological findings are similar to those for humans
with oral candidiasis. In addition, fungal culture results
demonstrated an average colonization of 2.0x104 CFUc/ml
in infected mice whereas the control mice harbored no C.
albicans as determined by plating.
Hst-5 levels to assess salivary Hst-5 protection
against candidal adherence and invasion, using
an organotypic model of human oral epithelium
tissue by quantification of tissue damage,
neutralization assays and histopathological
examination.
3- Determine the protective effect of salivary Hst-5
against C. albicans infection in-vivo, using a
mouse model for oral candidiasis.
Experimental animal models of mucosal
candidiasis have been invaluable in assessing fungal
pathogenicity and host immune defenses. These
studies have informed us that C. albicans is the most
virulent Candida species in-vivo and that the immune
response to Candida is different at various mucosal
sites, consequently highlighting the gaps in our
knowledge of Candida pathogenicity and host
immunity. Therefore, in order to accomplish Aim 3 of
our proposal in determining the role of host-produced
c: CFU = Colony Forming Unit.
Volume 46 - Nº 1 - 2009
Jabra-Rizk MA
peptides for their role in disease development and/or
progression, we have established a murine model of
sustained oral candidiasis currently utilized for in-vivo
testing of the efficacy of Hst-5 against oral
colonization and infection by C. albicans. In these
studies, three-month-old female CD1 mice are
immunocompromized, anesthetized and orallyinfected with 1x107 C. albicans cells. Four days postinfection, mice are euthanized and the tongue is
harvested and subject to histopathological analysis. As
seen in the images (Fig.3), both mycelial and
blastoconidial forms invaded the superficial epithelial
layer of the mucosa. The hyphae are seen invading the
parakeratin and spinous layers. The characteristic
finding of candidal dimorphism, embedded within the
parakeratin, can be seen using the PAS and H&E
stains. These histological findings are similar to those
for humans with oral candidiasis. In addition, fungal
culture results demonstrated an average colonization
of 2.0x104 CFU/ml in infected mice, whereas control
mice harbored no C. albicans as determined by plating.
Currently, these in-vivo studies are being performed
on mice orally treated with Hst-5 prior to and postinfection, in order to determine whether Hst-5 protects
the oral mucosa from C. albicans adherence.
Alternatively, Hst-5 will also be administered to mice
in drinking water throughout the course of infection, in
order to mimic the effect of constant exposure of saliva
on the health of the oral mucosa. This proposal is
currently awaiting funding from the National Institutes
of Health (NIH).
CONCLUSION
Recognizing the various factors and conditions that
play a role in candidal colonization and the
progression of colonization to infection will greatly
contribute to our understanding of the complex
mechanisms of the adaptability of C. albicans to its
environment, its pathogenesis and contributing host
factors. Such crucial information will have important
clinical implications as it aids in the identification and
design of novel therapeutic strategies aimed at the
prevention and/or treatment of infections. Specifically,
with the limited arsenal of antifungals available,
coupled with the increasing emergence of resistant
strains, the prospect of preventing C. albicans
Journal of the Lebanese Dental Association
colonization, thus precluding candidiaisis through
enhanced natural expression of innate peptides or their
development as alternative therapeutic agents, is
becoming increasingly attractive. Specifically, the
anti-candidal property coupled with its lack of toxicity
to human cells, makes Hst-5 a promising therapeutic
agent for the treatment or prevention of oral
candidiasis in immunocompromised individuals. The
dissemination of these new findings is therefore
crucial for the design of novel peptides for therapeutic
use for candidiasis, specifically those peptides based
on structure of histatins, which has been the focus of
much research lately. However, further in-depth
investigations are warranted in order to determine the
clinical implications of Hst-5 inactivation by C.
albicans, particularly in the immunocompromised
host.
Acknowledgements
The author wishes to thank her collaborators, Dr.
Tim Meiller, Dr. Mark Shirtliff, Dr. Mark Scheper and
Dr. Bernhard Hube. She would also like to thank
Alexandra Mae Rizk and Elie Jay Rizk for their
assistance in the manuscript.
REFERENCES
1- Calderone RA. ed. Candida and Candidiasis. 2002, ASM
Press: Washington.
2- Klein RS, et al. Oral candidiasis in high-risk patients as the
initial manifestation of the acquired immunodeficiency
syndrome. The New England Journal of Medicine 1987; 31:
354-358.
3- de Repentigny LD, Lewandowski P, Jolicoeur P.
Immunopathogenesis of oropharyngeal candidiasis in human
immunodeficiency virus infection. Clin Microbiol Rev
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4- Fidel PL Jr. Candida-host interactions in HIV disease:
relationships in oropharyngeal candidiasis. Adv Dent Res
2006; 19: 80-84.
5- Edgar WM. Saliva: its secretion, composition and functions.
Brit Dent J 1992; 172: 305-312.
6- Humphrey SP, Williamson RT. A review of saliva: normal
composition, flow, and function. J Prosth Dent 2001; 85:
162-169.
7- Helmerhorst EJ et al. Oral fluid proteolytic effects on histatin
5 structure and function. Arch of Oral Biol 2006; 51: 10611070.
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8- Gyurko C et al. Killing of Candida albicans by histatin 5:
cellular uptake and energy requirement. Antonie van
Leeuwenhoek 2001; 79: 297-309.
9- Helmerhorst EJ, Troxler RF, Oppenheim F.G. The human
salivary peptide histatin 5 exerts its antifungal activity
through the formation of reactive oxygen species. PNAS,
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10- Edgerton M et al. Candidacidal activity of salivary
histatins. J Biol Chem 1998; 272: 20438-20447.
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secreted aspartyl proteinases in virulence and
pathogenesis. Microbiol Molec Biol Rev, 2003; 67: 400428.
26. Albrecht A et al. Glycosylphosphatidylinositol-anchored
proteases of Candida albicans target proteins necessary for
both cellular processes and host-pathogen interactions. J
Biol Chem 2006; 281: 688-694.
11- Oppenheim F. et al. Histatins, a novel family of histidinerich proteins in human parotid secretion. J Biol Chem
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27- Naglik JR, Challacombe SJ, Hube B. Candida albicans
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12- Jainkittivong A, Johnson DA, Yeh CK. The relationship
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28- Meiller T.F. et al., A novel immune evasion strategy of
candida albicans: proteolytic cleavage of a salivary
antimicrobial peptide. PLoS ONE 2009; 4: e5039.
13- Helmerhorst EJ et al. The cellular target of histatin 5 on
Candida albicans is the energized mitochondrion. J Biol
Chem 1999; 274: 7286-7291.
29- Cannon RD, WL Chaffin. Colonization is a crucial factor in
oral candidiasis. J Dent Educ 2001; 65: 785-787.
14- Jang WS et al. The P-113 fragment of Histatin 5 requires a
specific peptide sequence for intracellular translocation in
Candida albicans which is independent of cell wall binding
Antimicrob Agents Chemother 2008; 52: 497-504.
15- Koshlukova SE et al. Salivary histatin 5 induces non-lytic
release of ATP from Candida albicans leading to cell death. J
Biol Chem 1999; 274: 18872-18879.
16- Lal K et al. Pilot study comparing the salivary cationic
protein concentrations in healthy adults and AIDS patients:
correlation with antifungal activity. Journal of Acquired
Immune Deficiency Syndrome and Human Retrovirology
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17- Mandel ID, Barr CE, Turgeon L. Longitudinal study of
parotid saliva in HIV-1 infection. J Oral Pathol Med 1992;
21: 209-213.
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Candida albicans: development, architecture, and drug
resistance. J Bacteriol 2001; 183: 5385-5394.
31- Meiller TF et al. A novel immune evasion strategy of
Candida albicans: proteolytic cleavage of a salivary
antimicrobial peptide. PLoS ONE 2009; 4: e5039.
Correspond wi th:
Mary Ann Jabra-Ri zk
[email protected]
This research was supported by the National Institutes of
Health / NIH grants DE14424 and DEO16257.
18- Torres SR et al. Salivary Histatin-5 and oral fungal
colonization in HIV+ individuals. Mycoses 2008;52:11-15.
19- Klein RS et al. Oral candidiasis in high-risk patients as the
initial manifestation of the acquired immunodeficiency
syndrome. N Engl J Med 1984; 311:354-358.
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albicans infection. Cur Opin Microbiol 2008; 11: 325-330.
24- Naglik JR et al. Candida albicans proteinases and
host/pathogen interactions. Cell Microbiol 2004; 6: 915926.
24
Volume 46 - Nº 1 - 2009
Laser Dentistry
Erbium: YAG Laser in everyday periodontal practice.
Zahi Badran1, Dr. Chi r. Dent. , CES Peri o. , DU Peri o. , MS , Céline Bories2, Dr. Chi r. Dent. ,
Assem Soueidan3 , Dr. Chi r. Dent. , Dr. Uni v. , HDR, PU, PH
A bst ract
Laser dentistry is becoming a fast growing dental discipline. Lasers are progressively being integrated in clinical protocols
and Laser Periodontology has evolved through the years after a disappointing start. In fact, multiple parameters determined the
possibility of using lasers in periodontal practice: nature of used lasers, form of tips, output settings, water irrigation…
Nowadays, many periodontal procedures could be performed safely with an acceptable efficacy.
In this article, we will review the main periodontal laser procedures, routinely performed at Nantes University Hospital.
The successful application of laser in different
medical fields such as ophthalmology, dermatology
and surgery1, 2 had a stimulating effect concerning
research on lasers in dentistry. The introduction of
lasers in dentistry3 opened new perspectives in
different therapeutic dental procedures. From the
beginning of the nineties, some commercially
motivated ideas presented laser as a magical
(promising) tool that could sometimes achieve all
therapeutic goals with superior results to all
conventional therapies, leading to some failure and
deception. Then, laser dentistry evolved progressively
toward a more scientific evidence-based approach,
which helped identify the indications for every kind of
laser.
In periodontal practice, many lasers were tested for
different purposes. Until now, results in literature are
sometimes inconsistent and contradictory, but a certain
consensus was elaborated over the years, considering
Erbium lasers as the most suitable lasers4 for hard
tissues ablation. Thus, Er:YAG (Erbium: yttriumaluminum-garnet) lasers are indicated for periodontal
1 University Hospital Teaching Assistant, Department of
Periodontology-ERT 2004, Faculty of Dental Surgery,
Nantes, France,
2 Intern in Odontology, Nantes University Hospital,
Nantes, France,
3 Chairperson and University (Full) Professor, Department of
Periodontology, Faculty of Dental Surgery, Nantes, France.
Journal of the Lebanese Dental Association
Volume 46 - Nº 1 - 2009
pocket debridement. This makes of Er:YAG a suited
laser for periodontal practice, especially that bone
surgery could also be performed with these lasers.
Also, many dental procedures are performed with
Er:YAG lasers: periodontal soft tissues surgery, cavity
preparation, dentine desensitization, oral lesions
treatment, laser bleaching….
This article focuses on the use of Erbium:YAG
laser in different periodontal treatments delivered at
the University hospital of Nantes (CHU de Nantes,
France). The clinical research carried out by our
department will also be exposed.
ERBIUM:YAG LASER
Laser is an acronym for Laser Amplification by
Stimulated Emission of Radiation. Light is generated
by electrical excitation of a YAG matrix doped with
erbium atoms. The emitted photons are amplified in a
parallel mirrors system, and the output beam is a
coherent, unidirectional and monochromatic light, of a
2.94 µm wavelength. The latter coincides with the
highest absorption coefficient of water. This specific
wavelength of Er:YAG lasers permits the ablation of
hard tissues without substantial damage to surrounding
sound tissues. In fact, when irradiating a hard tissue
with an Er:YAG laser, the instant absorption and
evaporation of water in the tissues will create an
internal pressure in the molecules, rapidly resulting in
25
Badran Z, Bories C, S oueidan A
a “micro explosion” and a localized ablation of
irradiated tissue, without melting or carbonization of
surrounding areas.
The device we are using is equipped with automatic
calculus detector (Kavo Key Laser 3®). The
technology is based on the differential fluorescence of
calculus and root surface when excited with a light of
a 655 nm wavelength. A feedback of the fluorescence
signal is analyzed by computer software. When
calculus is detected, therapeutic laser (2.94 µm) is
automatically activated until the fluorescence signal
disappears.
PERIODONTAL DEBRIDEMENT
The mechanical treatment of periodontal pockets
has always been the main therapeutic strategy for
controlling periodontal infection and eliminating
pockets. The main goal of this strategy is to
mechanically remove the subgingival plaque/calculus
and the contaminated superficial layer of root
cementum. Manual root planning (with curettes) or
ultrasonic scalers are used to reach this objective.
The laser Er:YAG was proposed as an alternative to
mechanical debridement. Few clinical studies have
evaluated the efficacy of laser debridement (LD) in
comparison to conventional mechanical treatments5,6.
The overall impression is that laser is equivalent or, at
best, slightly superior in terms of clinical output7. LD
was also found to be less time consuming than
ultrasonic debridement when used in combination with
a calculus detection device8. Concerning the property
of laser to be bactericidal, in vitro studies confirmed
that laser irradiation has an antibacterial effect9.
Though, in a clinical study, 1 month after treatment,
bacterial reduction after LD was not significantly
different compared to that observed after mechanical
treatment10.
Another
subjective
impression
frequently
expressed by laser clinicians and patients, is LD being
more comfortable and less painful. In our routine
activity at Nantes University Hospital (CHU)*, we
share this impression, noting that most LD sessions are
performed without local injection of anesthetics or
with an anesthetic periodontal gel (Oraqix®).
Actually, we are conducting a clinical pilot study,
comparing the clinical output of Er:YAG laser
debridement (Fig. 1) to conventional manual root
planning. In this study, a split moth design was
adopted. Laser is used with the calculus detection
feature. Clinical parameters (attachment loss, probing
depth and bleeding on probing) as well as
microbiological changing will be monitored 2 months
after initial non surgical treatment.
DENTINE DESENSITIZATION
Dentinal hypersensitivity (DH) is a frequent
manifestation affecting 4-57% of the general
population. Pain caused by DH could influence the
quality of life and the well-being of affected patients.
The etiology of DH is an exposed area of dentinal
tubules; this is a result of enamel and/or cementum
loss. Pain triggering stimulus can be thermal, chemical
or mechanical. It is admitted that different stimuli
initiate a movement of the dentinal fluid, stimuli hence
generating pain.
DH treatment aims to obliterate the exposed
dentinal tubules. Different desensitizing products are
used for this purpose, enriched with fluorides or
potassium nitrates and prescribed in different forms:
toothpastes, mouthrinces, topical gels, etc...
Recently, laser desensitization (LDS) was proposed
as a therapeutic alternative to conventional treatment
modalities, with an equivalent efficacy11,12. The main
advantage of laser is that instant pain relief could be
achieved in 50-60 seconds in a one-session treatment
(Fig. 3). Our preliminary in-vitro research showed that
Er:YAG laser, when used at a low frequency and
intensity (60 mj, 2Hz) initiates a mild superficial
melting of dentin (Fig. 2). This melting will obliterate,
partially or totally, the exposed dentinal tubules. In
clinical practice, severe DH cases were successfully
treated by LDS, where irradiation of exposed dentin
could be painless for few seconds, then pain
diminishes rapidly, and the result is instantly felt by
patient after 40-50 seconds of irradiation. One of the
limits of LDS is that exposed area should not be in
proximal areas where access of laser beam is
impossible. Long-term follow-up is necessary to
confirm the stability of LDS initial results.
* CHU = Centre Hospitalier Universitaire
26
Volume 46 - Nº 1 - 2009
Badran Z, Bories C, S oueidan A
SOFT TISSUES SURGERY AND ORAL
LESIONS
Er:YAG lasers can be successfully used to perform
different types of minor soft tissues surgery:
gingivectomy, frenectomy, fibroma elimination…The
main advantage of laser is its capacity to initiate blood
coagulation and to allow instant control of postsurgical
bleeding. As previously explained, Er:YAG laser is
rapidly absorbed by water and heat propagation in
tissues is relatively low: this characteristic permits a
safe soft tissue ablation, with minimal thermal damage
to surrounding tissues, but it also makes the
procedures time consuming in comparison to other
lasers (Nd:YAG, Diode lasers…). We have found
Er:YAG lasers particularly useful in performing
frenectomy in young patients. In fact, no sutures are
needed, postsurgical bleeding and pain are minimal
and sometimes nonexistent. We should also note that
in some cases, we carried out laser gingival surgery,
using only topical gel anesthetic. But we emphasize
that this is patient dependent and not all laser surgeries
could be performed without a conventional intramucosal analgesia injection.
Another indication for Er:YAG laser is the
symptomatic treatment of oral lesions such as gingival
aphtous ulcers (Fig. 4). In our practice, ER:YAG laser
was effective in substantially reducing pain caused by
aphtous lesions. Nevertheless, the healing period was
not always reduced by Er:YAG laser irradiation.
Conventional treatments of peri-implant mucositis
or peri-implantitis consist of a mechanical
debridement using non-metallic curettes or ultrasonic
tips (plastic, Teflon, etc...). Lasers were suggested as
alternatives to these modalities13. The rationale behind
this is that laser beam does not cause any damage to
the metallic implant surface. Laser light could also
decontaminate the entire implant surface, even the
rough surface type, in comparison to mechanical
treatment where the tip of the curette or the scaler
cannot effectively reach the microstructure.
We have combined mechanical and photonic (laser)
treatments in the management of peri-implant
infections (Figs. 5 A,B,C). We have been using Teflon
Fig. 1. A: Chisel shaped tip for root debridement.
B: Laser debridement of a periodontal pocket. A
B
Control
samples
of dentine
with
tubules,
Fig. 2. A:
exposed
observed using a scanning electron microscope.
B: Microscopical obliteration of dentinal
tubules after 60 sec
of irradiation (E: 60mJ, Fr: 2Hz) (Original
magnification:
x3000).
TREATMENT OF PERI-IMPLANT
INFECTIONS
Fig.
of a probe.
3. A: Detection of painful area using the tip
B: Protection of soft tissues with a wet gauze and Er:YAG
laser
area
irradiation of hypersensitive
Fig.
4. A: Painful aphtous ulceration localized in the buccal
maxillary
mucosa. B: Laser irradiation of the lesion with an
Er:YAG device (E: 100mJ, Fr: 6Hz). C: Healing, one week
post-treatment, pain decreased substantially 24 hours after
the laser session and, after 2 days, it was almost inexistent.
27
Journal of the Lebanese Dental Association
Badran Z, Bories C, S oueidan A
ultrasonic tips for the initial debridement, followed by
an Er:YAG laser decontamination carried out
thoroughly. A specific beveled, round shaped laser tip
is used. The latter provides an angulated secondary
beam directed towards the implant surface (Fig. 5.C).
Preliminary results show that this protocol could
induce a significant reduction of probing depth and
peri-implant inflammation. A research protocol to
determine the efficacy of implant LD is under
preparation.
CONCLUSION
Er:YAG laser is a polyvalent tool laser that can be
used in a variety of dental procedures. In periodontal
practice, Laser debridement seems to be a promising
alternative to mechanical debridement. Our present
knowledge suggests that it can be effectively used to
treat periodontitis, with a clinical output comparable or
slightly superior to conventional treatments. However,
clinical studies are still insufficient to emit an
evidence-based conclusion about clinical relevance of
laser debridement in comparison to mechanical
debridement.
For desensitization, Er:YAG laser appears to be a
promising novel therapy, with an instant clinical
efficiency. The acceptance of patients has been an
interesting advantage found in clinical trials. A onesession laser could be a valuable starting point for DH
treatment and desensitizing chemicals (mouthwashes,
toothpastes, fluoride gels…) could be later prescribed
as an adjuvant since they access proximal
hypersensitive spots. A new protocol is being
investigated (Data not shown) with encouraging
preliminary results. It consists of applying a
desensitizing topical fluoride paste (Durafat®) and
irradiating the hypersensitive area with an Er:YAG
laser.
In dental literature, a large amount of case reports
suggested the efficacy of different lasers in the
management of benign oral lesions. Lasers could be
useful to treat pain and/or to accelerate healing
process. Our experience confirms this clinical
impression. However, the biological effect of lasers on
these oral lesions is not well elucidated. Controlled
clinical trials are also needed to determine the real
efficacy of lasers compared to conventional
28
Fig. 5. A: Periimplant attachment loss. B: Teflon ultrasonic
inserts are used for implant debridement as a first step. C,D:
Er:YAG laser debridement is then performed using a conic
shaped tip.
symptomatic treatments.
For peri-implant infection, Er:YAG laser seems
indicated to implant surface debridement. In-vitro data
confirmed its antibacterial effect on titanium
surfaces14.
In conclusion, lasers, generally, and Er:YAG
particularly, are starting to gain their place in the
general dental or specialist periodontal office. The
indications of Er:YAG laser treatment are in constant
development with the introduction of new protocols.
More time is however needed to establish an evidencebased knowledge concerning lasers procedures.
Furthermore, controlled clinical trials are required to
determine the relevancy of different laser protocols in
clinical practice.
Acknowledgements
We would like to thank Kavo France for supporting
our clinical research and for its contribution to the
doctorate (Doctorat d’Université) project of Dr. Zahi
Badran.
REFERENCES
1- Steinert RF. Femtosecond laser enabled keratoplasty (FLEK).
Ann Ophthalmol (Skokie) 2009; 41:6-9.
2- Winstanley DA, Uebelhoer NS. Future considerations in
cutaneous photomedicine. Semin Cutan Med Surg 2008; 27:
301-308.
Volume 46 - Nº 1 - 2009
Badran Z, Bories C, S oueidan A
3- Stern RH, and Sognnaes RF. Laser inhibition of dental caries
suggested by first tests in vivo. J Am Dent Assoc 1972; 85:
1087-1090.
4- Cobb CM. Lasers in periodontics: a review of the literature. J
Periodontol 2006; 77: 545-564.
5- Schwarz F et al. Clinical evaluation of an Er:YAG laser
combined with scaling and root planing for non-surgical
periodontal treatment. A controlled, prospective clinical
study. J Clin Periodontol 2003; 30: 26-34.
6- Schwarz F et al. Periodontal treatment with an Er: YAG laser
compared to scaling and root planing. A controlled clinical
study. J Periodontol 2001; 72: 361-367.
7- Schwarz F et al. Laser application in non-surgical
periodontal therapy: a systematic review. J Clin Periodontol
2008; 35(8 Suppl): 29-44.
8- Schwarz F, et al. Influence of fluorescence-controlled Er:YAG
laser radiation, the Vector system and hand instruments on
periodontally diseased root surfaces in-vivo. J Clin
Periodontol 2006; 33: 200-208.
9- Folwaczny M et al. Antimicrobial effects of 2.94 microm
Er:YAG laser radiation on root surfaces: an in-vitro study. J
Clin Periodontol 2002; 29: 73-78.
10- Tomasi C et al. Short-term clinical and microbiologic
effects of pocket debridement with an Er:YAG laser during
periodontal maintenance. J Periodontol 2006; 77:111-118.
11- Birang R, et al. Comparative evaluation of the effects of
Nd:YAG and Er:YAG laser in dentin hypersensitivity
treatment. Lasers Med Sci 2007; 22: 21-24.
12- Dilsiz A et al. Clinical Evaluation of Nd:YAG and 685-nm
Diode Laser Therapy for Desensitization of Teeth with
Gingival Recession. Photomed Laser Surg 2009; 27:1-6.
13- Kreisler M et al. Bactericidal effect of the Er:YAG laser on
dental implant surfaces: an in-vitro study. J Periodontol
2002; 73: 1292-1298.
14- Matsuyama T et al. Effects of the Er:YAG laser irradiation on
titanium implant materials and contaminated implant
abutment surfaces. J Clin Laser Med Surg 2003; 21: 7-17.
Correspond with:
Assem Soueidan
[email protected]
Journal of the Lebanese Dental Association
29
Adhesive Dentistry Research
Effect of different surface treatments on bond strength and failure
type of zirconium oxide ceramic: an in-vitro study.
Ziad Salameh1, Dr. Chir. Dent, DES (Prostho. ), M. S c. , FICD, Ph. D, Joseph Hobeiche2, Dr. Chir. Dent, DU
(Occlusodont. ), DEA, MBA, Dr. Univ. (US J), Hani Ounsi3, Dr. Chir. Dent, DES (Endo. ), M. S c. (Dental
Mat. ), FICD, MRACDS (Endo. ), Mousatafa Aboushelib4, BDS , MS c. , Ph. D
A bst ract
S t at em ent of probl em : Establishing a reliable bond to zirconia-based materials has proven to be difficult, making it the
major limitation against fabrication of adhesive zirconia restorations.
Purpose: The aim of this in-vitro study was to determine the ability of a new experimental primer to improve the bond
strength between resin cement and zirconium oxide based crowns.
Mat eri al s and Met hods: 15 resin-composite discs (Filtek Supreme, 3M-ESPE) were cemented on top of zirconia discs
(Lava, 3M-ESPE) using resin cement (Panavia F2.0, GC), four test groups (n=15) according to zirconia surface treatment were
identified: group 1(control) with no treatment of the zirconia surface, group 2 the zirconia disc was sandblasted prior to bonding
procedures, in group 3 zirconia disc was coated with Panavia primer agent, and in group 4 the sandblasted zirconia disc was coated
with an experimental primer. Micro-shear bond strength was performed and failure type was evaluated under Scanning Electron
Microscopy-SEM.
R esul t s: One-way analysis of variance followed by multiple comparison were conducted. There was no significant difference
between group 1, group 2 and group 3, while significant difference was noted between the previous groups and group 4 (P<0.05).
SEM observations of the specimens showed predominant interfacial failure type, especially in groups 1, 2 and 3; while in group
4 there was a predominant cohesive failure type between adhesive cement and resin composite.
INTRODUCTION
The introduction of zirconia to the dental field
opened up the design and application limits of allceramic restorations. The superior mechanical
1 Assistant Professor and Researcher, King Saud University
College of Dentistry, Riyadh, Saudi Arabia and Assistant
Professor, Department of Research, Lebanese University
School of Dentistry, Beirut, Lebanon,
2 Assistant Professor, Department of Fixed Prosthodontics
and Occlusion, Saint-Joseph University Faculty of Dental
Medicine, Beirut, Lebanon, and Private Practice, Doha,
Qatar,
3 Ph.D student, S iena University School of Dentistry,
Department of Endodontics, Siena, Italy, and Part-time
Faculty, Kuwait University Health Sciences Center,
Faculty of Dentistry, Department of Restorative Sciences,
4 Assitant Professor, Department of Dental Biomaterials,
Faculty of Dentistry, Alexandria University Faculty of
Dentistry, Egypt and Researcher, Dental Materials
Science, Academic Centre of Dentistry Amsterdam
(ACTA), University of Amsterdam and Free University,
The Netherlands.
Journal of the Lebanese Dental Association
Volume 46 - Nº 1 - 2009
properties of zirconia combined with the state-of-theart CAD/CAM fabrication procedure allowed the
production of large and complex restorations with high
accuracy and success rate1. In contrast to conventional
felspathic ceramic, the matrix pressure on the
tetragonal particles of zirconium oxide is reduced by
tensile stresses that induce a transformation of the
tetragonal to a monoclinic phase, known as the
transformation toughening property; this is associated
with a localized volumetric increase of 3% to 5%,
resulting in compressive stresses that counteract the
external tensile stresses and, in this way, may prevent
cracks from propagating2, 3. Based on these material
properties, it is expected that restorations with a
zirconium oxide core are able to withstand the high
occlusal stresses occurring during function4 and that
extensive all-ceramic restoration exceeding the limit
of four units are within reach.
Due to their chemical inertness, zirconia
frameworks are resistant to aggressive chemical
33
S alameh Z, Hobeiche J, Ounsi H, Aboushelib M
agents, such strong acids as hydrofluoric acid5, alkalis
or organic and inorganic dissolving agents. On the
other hand, establishing a chemical bond with these
materials was proven to be difficult, as they do not
respond to common bonding methods used with other
glass containing ceramics, as acid etching and
silanation.6
Different investigations have examined and
measured the shear bond strength of different cements
on zirconium oxide ceramic surface after different pretreatment; these studies providing varying and
controversial results.5, 7, 8, 9
Pre-treatment of zirconium oxide surface by micro
roughness may influence micromechanical interlocking
of bonding and composite resin luting agents.6
Recently Aboushelib and co-workers10 introduced a
novel etching technique of zirconia surface that
significantly increased the bond strength to resin based
materials.
Another recent study by Ernest and co-workers11
investigating the bonding potential of different resin
cement used in combination with zirconia-based
restorations showed superior values obtained with a
composite resin cement containing an adhesive
phosphate monomer. 7, 8
According to recent studies, the combination of
airborne-particle
abrasion
and
10
methacryloyloxydecyldihydrogenphosphate (MDP)
monomer is the recommended method for bonding
resin-composites to zirconia12.
A recent study showed a significant increase in
resin composite bond strength values when combining
a selective infiltration etching procedure with an
experimental primer.13
The micro-shear bond test method for measuring
bond strength was introduced in 200214, and compared
with the conventional shear bond test, the stress
distribution proved to be more concentrated at the
interface in the micro-shear bond test15 which reduces
chances of cohesive failure in the material that does
not represent the “true” interfacial bond strength.
The aim of this study was to evaluate the resincomposite micro-shear bond strength (MSBS) to
zirconia, using different techniques of surface
treatment. The null hypothesis tested was that there
was no difference between different surface treatments
on bond strength of resin composite to zirconia.
34
MATERIALS AND METHODS
Preparation of specimens and bonding procedure
Fully sintered zirconia (Lava, 3M-ESPE, Seefeld,
Germany) discs (ø 19.5 mm x 3 mm high) were used
in combination with resin-composite (Filtek Z250,
shade A2; 3M ESPE, St. Paul, MN, USA) micro-discs
(1 mm in diameter × 3 mm height) that were prepared
by injecting resin composite into a plastic mold which
was held between two glass plates and light
polymerized for 20 seconds from the top and for 20
seconds from the bottom (Elipar FreeLight 2; 3M
ESPE, Seefeld, Germany). The specimens were then
ground, using 600 grit silicon carbide wet abrasive
paper to remove any excess and ensure parallelism of
the surfaces after which the specimens were stored in
distilled water at 37˚C for 24 hours prior to removal
from the plastic mold.
Specimens were divided in four groups, as follows:
Group 1 (control): 10 resin-composite discs (n=15)
were bonded on top of the surface of the zirconia disc,
using resin composite cement (Panavia F 2.0; Kuraray
Co. Ltd., Tokyo, Japan) under a fixed load of 20 N.
Excess cement was wiped off and an air barrier gel was
applied before light curing, using a light cure machine
(Elipar FreeLight 2; 3M-ESPE, Seefeld, Germany).
Group 2: n=15: same procedure as group 1 but
zirconia disc was sandblasted (with a 50µm abrasive
particles.) prior to bonding procedures.
Group 3: n=15: same procedure as group 2 but the
sandblasted zirconia disc was coated with Panavia
primer agent (ED Primer II, Panavia) prior to bonding
procedures.
Group 4: n=15: same procedure as group 2 but the
sandblasted zirconia disc was coated with an
experimental primer as described by Aboushelib and
co-workers13 (The silane monomers used in the
primers were: 3-acryloyloxypropyltrim ethoxysilane,
3-isocyanatopropyltriet-hoxysilane,
styrylethyltrimethoxysilane,
3- methacryloyloxypropyltrimethoxysil-ane and 3-(Nallylamino) propyltrimet- hoxysilane) prior to bonding
procedures.
Testing procedure
MSBS was measured by applying an axial load on
the bonded interface, using a universal testing machine
Volume 46 - Nº 1 - 2009
S alameh Z, Hobeiche J, Ounsi H, Aboushelib M
(Instron, Accuforce elite test stand) (Fig. 1).
Failure load (N) was extracted from computer
generated data files.
The broken resin discs and zirconia discs were
ultrasonically cleaned, dried, gold sputter coated and
examined under a scanning electron microscope-SEM
(JEOL, JSM-6360LV, Japan) and failure type was
classified into interfacial failure across the
zirconia–resin interface, resulting in exposure of the
zirconia surface or cohesive failure in the composite
material or the adhesive resin.
One-way analysis of variance (ANOVA) was used
to analyze data with level of significance α=0.05. The
Kolmogorov-Smirnov post-hoc test was used for
multiple comparison.
Fig. 1: MSBS testing.
RESULTS
Data analysis revealed no significant difference
between group 1, group 2 and group 3 (Table 1), while
significant difference was noted between the previous
groups and group 4 (P<0.001).
SEM observations of the specimens showed
predominant interfacial failure type, especially in
groups 1, 2 and 3; while in group 4 there was a
significant predominant cohesive failure type between
the adhesive cement and the resin composite (Fig. 2).
Fig. 2: SEM showing the predominant cohesive failure type
between adhesive cement and resin composite.
DISCUSSION
The results of this study led to reject the null
hypothesis tested implying that there was no
significant difference in bond strength between the
tested groups.
One of the most common methods for evaluating
adhesive properties of restorative materials is bond
strength measurement since the development of the
micro-tensile bond strength test by Sano and coworkers16,17, many micro-bond tests were performed
showing the effective of this method in testing small
areas of tooth structure18, micro-shear bond strength
allows straightforward sample preparation giving
precise results, preserving the uniformity of the testing
area16, 18,19.
The low bond strength obtained in group 1 with no
treatment of the zirconia surface were in agreement
with results reported by other studies 20. Such findings
indicate that establishing a strong chemical bond with
zirconia is a difficult procedure for the MDPcontaining resins when not combined with airborne
particle abrasion as a recommended surface pretreatment.
The use of air-abrasion particles as surface
treatment increased bond strength, indicating that
mechanical retention is necessary to gain benefit for
MDP resin composite as reported in previous study21,
Journal of the Lebanese Dental Association
MPa = Mega Pascal.
SD = Standard Deviation.
n = sample size.
Group
Mean (i n MPa)
SD
n
1a
10.43
3.8
15
2a
12.17
4.2
15
3a
13.03
4.8
15
4b
32.56
10.21
15
Table 1: MSBS of different groups (MPa), groups with
same letter were not significantly different.
35
S alameh Z, Hobeiche J, Ounsi H, Aboushelib M
while the combination of sandblasting with primer
agent coating of the zirconia disc showed no difference
with only sandblasted specimens.
Results of this in-vitro study showed that
significant difference was only observed with group 4
where the experimental primer was used, explained by
the presence of an organ functional silanes in the
primer composition and their chemical reactivity with
the sandblasted zirconia surface, enhancing the
adhesion between MDP-cement and the treated
surface.
SEM observation revealed that in the group using
the experimental primer,the predominant failure type
was cohesive in the composite material or the adhesive
resin, explained by better adhesion obtained with the
novel primer, while the failure type observed in the
other groups was more interfacial type due to the weak
bond achieved.
8- Kern M,Wegner SM. Bonding to zirconia ceramic :adhesion
methods and their durability .Dent Mater 1998;14:64-71 .
CONCLUSION
15- Banomyong D, Palamara J, Burroe MF, Messer HH. Effect of
dentin conditioning on dentin permeability and microshear bond strength. Eur J Oral Sci 2007;115:502-509.
Within the limitations of this in-vitro study, the use
of an experimental primer achieved a better bond
strength in combination with air-abrasion particles.
Further studies are warranted to evaluate the optimal
zirconia surface treatment in order to enhance the
clinical use of bonded-zirconia restorations .
REFERENCES
1- Aboushelib MN, de Jager N, Kleverlaan CJ, Feilzer AJ. Effect
of loading method on the fracture mechanics of two layered allceramic restorative systems. Dent Mater 2007;23:952–959.
2- Christel P, Meuniere A, Heller M, TorrJp, Peille CN.
Mechanical properties and short –term in-vivo evaluation of
yttrium-oxide –partially stabilized zirconia .J Biomed Mater
Res 1989;23:45-61.
3- Luthardt RG, Holzhuter M, Sankuhl O, Herold V, Schnapp
JD.Kuhlisch E, et al. Reliability and properties of ground YTZP-Zirconia ceramics.J Dent Res 2002;81:487-491.
4- Guazzato M, Proos K, Quach L, Swain M. Strength,
reliability
and mode of fracture of bilayered
porcelain/zirconia (Y-TZP) dental ceramics. Biomaterials
2004;25:5045–5052.
5- Derand P,Derand T.bond strength of luting cements to zirconium
oxide ceramics .Int J Prosthodont 2000;13:131-135.
6- Blatz MB, Sadan A, Kern M.Resin-ceramic bonding: A review
of the literature. J Prosthet Dent 2003;89:268-274.
7- Blatz MB,Sadan A, MMartin J,Lang B.In vitro evaluation of
shear bond strengths of resin to densely-sintered high-purity
zirconium oxide after long-term storage and thermal cycling.
J Prosthet Dent 2004;91 :356-362.
36
9- Piwowarczyk A Lauer HC, Sorensen JA. The shear bond
strength between luting cement and zirconia ceramics after
two pre- treatment .Oper Dent 2005;30:382-388.
10- Aboushelib MN, Kleverlaan CJ, Feilzer AJ. Selective
infiltration-etching technique for a strong and durable bond
of resin cements to zirconia-based materials. J Prosthet
Dent 2007;5:379-388.
11- Ernest CP, Cohnen U, Stender E, Willershausen B. In-vitro
retentive strength of zirconium oxide ceramic crown using
different luting agents. J Prosthet Dent 2005;93:551-558.
12- Matinlinna JP, Heikkinen T, Ozcan M, Lassila LV, Vallittu
PK. Evaluation of resin adhesion to zirconia ceramic using
some organosilanes. Dent Mater 2006;22:824–831.
13- Aboushelib MN, Matinlina JP, Salameh Z, Ounsi HF.
Innovations in bonding to zirconia-based materials:Part I.
Dent Mater 2008 (Electronic publication).
14- Mcdonogh WG, Antonucci JM, He J, Shimada Y, Chiang
MYM, Shumacher GE, Schultheisz CR. A microshear test to
measure bond strengths of dentin-polymer interfaces.
Biomaterials 2002;23:3603-3608.
16- Sano H, Shono T, Sonoda H, Takatsu T, Ciucchi B, Carvalho
R, Pashley DH. Relationship between surface area for
adhesion and tensile bond strength. Evaluation of a microtensile bond test. Dent Mater 1994;10:236-240.
17- Shimada Y, Yamaguchi S, Tagami J. Micro-shear bond
strength of dual-cured resin cement to glass ceramics. Dent
Mater 2002;18:380-388.
18- Kanemura N, Sano H, Tagami J. Tensile bond strength to and
SEM evaluation of ground and intact enamel surfaces. J Dent
1999;27:523-530.
19- Senawongse P, Sattabanasuk V, Shimada Y, Otsuki M,
Tagami J. Bond strength of current adhesive systems on
intact and ground enamel. J Esthet Restor Dent
2004;16:107-115.
20- Bottino MA, Valandro LF, Scotti R, Buso L. Effect of surface
treatments on the resin bond to zirconium-based ceramic.
Int J Prosthodont 2005;18:60–65.
21- Amaral R, Ozcan M, Bottino MA, Valandro LF. Microtensile
bond strength of a resin cement to glass infiltrated zirconiareinforced ceramic: the effect of surface conditioning. Dent
Mater 2006;22:283–290.
Correspond with:
Ziad Salameh
[email protected]
[email protected]
Volume 46 - Nº 1 - 2009
Craniomandibular disorders
Temporomandibular disorders (TMDs): a note from the field.
Nabil Tabbara*, DMD, FAAFO, FAACP
A bst ract
Temporomandibular disorders (TMDs) have become of increasing interest to dental professionals worldwide. While there may
be controversy regarding this topic, it is widely agreed that these pathologies remain largely under-diagnosed. In an effort to shed
some light on these disorders, a brief discussion of aetiology, diagnosis and possible treatments as well as a description of the
leading opinions within our profession will be highlighted.
TMD is defined8 by the American Academy of
Craniofacial Pain as a number of clinical problems that
involve masticatory muscles, temporomandibular joint
(TMJ) or even both (de Leeuw, 2008).
Temporomndibular joint (TMJ) is a paired synovial
joint capable of both gliding and hinge movements,
articulating mandibular condyle, articular disc and
squamous portions of temporal bone (de Leeuw,
2008).
Epidemiological studies conducted on a crosssection of selected non-patient adult populations have
shown that 40-75% of studied individuals presented a
minimum of one sign of joint dysfunction2. Examples
of such joint dysfunctions include, but are not limited
to: movement abnormalities, joint noise and
tenderness upon palpation. Furthermore, a striking
proportion (approximately 33%) of selected nonpatient populations has a minimum of one symptom of
dysfunction, such as face or joint pain (de Leeuw
2008, Rugh et al., 1985, Schiffman et al., 1988, De
Kanter et al., 1993, Dworkin et al., 1990). These
striking statistics highlight the prevalence of TMD and
emphasize the importance for dental professionals to
address these pathologies within their practices.
According to The American Dental Association
(ADA), it is the general dental practitioner’s (GDPs)
role to identify, diagnose, and manage or refer for
treatment of TMDs. This role has been taken more
seriously and frequently by an increasing number of
dentists in the past ten years. This increase in interest
can be related to advancements in research, as well as
higher attendance at related meetings, conferences,
workshops and courses.
In addition to GDPs and dental specialists,
including orthodontists, maxillofacial surgeons and
oral medicine specialists, the domain of TMD is also
being explored by medical doctors, radiologists,
orthopaedic surgeons, physiotherapists, chiropractors,
osteopaths, massage therapists, craniosacral therapists,
psychologists11,22,24 and Chinese medicine practitioners.
With such a diversity of dental, medical and
paramedical professions, we are presented with a
tremendous opportunity to unite in an effort to provide
our patients with the highest degree of care possible
within an environment of teamwork and useful cooperation. We, as dental practitioners, could greatly
benefit from forming an inter-professional team with a
common understanding to cross-refer patients as
needed. This sort of approach is especially relevant in
managing patient care involving pathologies with
multifactorial aetiologies, such as TMDs.
* Adjunct Clinical Professor, Schulich School of Medicine
and Dentistry, University of Western Ontario, London,
Canada.
Journal of the Lebanese Dental Association
Volume 46 - Nº 1 - 2009
37
Tabbara N
TMDs ETIOLOGY
The underlying causative factors of TMD, and by
extension the diagnosis, prognosis and treatment, are
perceived differently, depending on which dental
school of thought one subscribes to. The American
Academy of Orofacial Pain (AAOP) and the American
Academy of Craniofacial Pain (AACP) are two of the
main organizations specializing in this field. Both
groups seem to agree with the classification of
aetiological factors into: predisposing, initiating and
perpetuating factors (de Leeuw 2008, McNeill et al.,
1983, McNeill et al., 1980, Fricton et al., 1988).
These factors can be summarized as follows:
* Trauma; classified as acute or chronic, macro or
micro.
* Anatomical factors; skeletal and/or occlusal
* Systemic factors; require the involvement of
medical specialists and may be degenerative,
endocrine, genetic, neurologic, neoplastic,
infectious, rheumatologic, or vascular (Byrd et
al., 1990- Hagberg et al., 1990)
* Muscular hyperactivity, hyperexcitability and
hyperalgesia (Reid et al. ,1994-Browne et al.,
1993- Clark et al., 1993- Hu et al.,1993)
* Intra-articular pathology, such as: disc
displacement6, stickiness, deformation, ligaments
fibrosis, elongation or inefficient functioning of
synovial fluid,
* Psychosocial factors11,22,24 (Rugh et al. ,1979Eversole et al., 1985- Southwell et al.,1990- Flor
et al., 1991).
However, the importance of these factors are
assessed differently between these groups. The AACP
advocates to emphasize on the importance of the
biomechanical model (occlusion, condylar position
,etc...), while the AAOP highlights the significance of
the biomedical and psycho-social model where
individual differences, such as genetic predisposition
and psychological factors, are thought to be of utmost
importance (de Leeuw 2008- McNeill et al., 1983McNeill et al., 1980- Fricton et al., 1988).
The main points of inquiry seem to be as follows:
* Whether or not the occlusion represents a
significant aetiological factor in TMD,
* Whether or not the majority of TMDs are selflimiting or progressive. If some are progressive,
38
do they warrant treatment? How successful is that
treatment?
* Whether or not there is a significant relationship
between neck and body posture and their effect(s)
on TMJ stability.
The AACP states that occlusion and condylar
position are often two important factors in TMJ
pathology, for two reasons:
1. Mandibular condyle has to be positioned in a
physiologically acceptable position to allow the
articular disk to contribute to TMJ health,
2. When dental arches do not satisfy certain
conditions of interrelationships, muscles of
mastication may sometimes lose their synchronicity
and mutual protection, thus negatively influencing
head and neck muscles, and possibly leading to spasm,
inflammation and pain3,15.
But some authors (Henrikson and Nilner, 2003McNamara, Seligman and Okesson, 1995) claim that
this argument is invalid and does not hold the road, as
patients who undergo orthodontic treatments do not
suffer from spasms, inflammation or pain because of
badly related jaws nor they consult for such reason(s).
The same also applies for those patients who sustain
orthodontic treatment coupled with an orthognatic
surgery procedure.
Therefore, biomechanical strains often lead to loss
of structural integrity and function. This can in turn
decrease the adaptability, thus increasing the chance of
dysfunction and pathology (Dijkgraaf et al., 1995).
The AAOP position follows the biomedical model
of injury and healing. It expects the body to heal/be
asymptomatic, whether the disc is properly positioned
or not, and the pain/inflammation to be a temporary
occurrence in the majority of cases (de Leeuw 2008Seligman et al., 2000- Pullinger et al., 2000- De
Boever et al., 2000). Since teeth do not occlude more
than 15-17 minutes daily, occlusion is not expected to
cause significant harm. Consequently, it is
unjustifiable to treat the majority of patients with
TMDs, except to manage their signs and symptoms for
a period of time until body adjusts and possibly heals.
This reasoning is based on the belief that body insult
or injury is met with adaptive physiological responses,
such as muscle tone regulation and tissue remodeling.
In other words, the first view is more curative, often
Volume 46 - Nº 1 - 2009
Tabbara N
mechanical, while the second is palliative. The first
relies on diagnosing the specific pathology of TMD
(whether it is muscular or intracapsular) through the
use of various diagnostic procedures and treating each
pathology distinctly, whereas the second treats
symptoms while allowing the body undergo the
healing.
DIAGNOSIS OF TMDs
8,13
Reaching a precise diagnosis is of utmost
importance in managing a pathology, and TMDs are,
of course, no exception. In order to identify the nature
of illness ,the AACP suggests the following tools to
establish a diagnosis:
* Clinical examination:
- Medical and dental history, previous treatments,
evolution of symptoms, history of trauma (macro
or micro), range of motion, muscle palpation and
identification of trigger points (in myofascial
pain) or tender points (as in fibromyalgia). This
examination commonly requires two hours.
* Radiographs:
- Cephalometric view(frontal and lateral cervical) to
analyze relationships of jaw bones to the rest of
the skull, the hyoid and cervical vertebrae),
panoramic radiograph to identify any major bone
discrepancies, fractures or anomalies, tomographic
cuts to study position(s) of mandibular condyle,
shape and texture of
articular surfaces,
Computerized Axial Tomography (CAT) scan and
even Magnetic Resonance Imaging (MRI) to
visualize more structures including TMJ’s disc
and other soft tissues.
* Dental models to analyze occlusion:
- Premature contacts- especially balancing
contacts, cross-bites, wear facets pattern,
deviation of skeletal midlines, to confirm slants in
the occlusion seen on radiographs. Mounting on
an Acculiner is suggested (www.acculiner.com).
* Biometrics:
- Computerized analyses for advanced diagnostics:
Joint Vibration Analysis, Jaw Tracking and
Electromyography. Two companies providing
these instrumentations for TMD, head, neck and
facial pain as well as for neuromuscular dentistry
are: Bioresearch Inc. (www.biojva.com) and
Journal of the Lebanese Dental Association
Myotronics
(www.myotronics.com).
These
means are accepted only as complementary
diagnostic measures not necessary for the proper
diagnosis of TMDs.
The International Headaches Society has outlined
specific diagnostic classifications of TMDs based on
whether the patient is thought to have a TMJ articular
(intracapsular) disorder or a disorder of the
masticatory muscles (extracapsular).
These are
especially helpful to consider when establishing a
diagnosis. The subclassifications for a TMJ articular
disorder are as follows: congenital or developmental,
(i.e. aplasia, hyperplasia, hypoplasia, dysplasia and
neoplasia), disc displacement with and without
reduction, TMJ dislocation, inflammatory disorders
(i.e. synovitis, capsulitis), degenerative disorders (i.e.
osteoarthritis9), ankylosis and lastly, fractures. The
subclassifications for masticatory muscle disorder are
as follows: Myalgia, myofascial pain, myospasm,
myofibrotic contracture, myositis and neoplasia.
TREATMENT OF TMDs2,6,7,8,13,14,16,17,18,19
Dental treatments of TMD are specific to each type
of disorder, the main sub-classifications, as mentioned
earlier, are either muscular/extracapsular or
articular/intracapsular/internal derangements. Also of
importance is whether the pathology is acute or
chronic.
Muscular pathology is treated in a conservative
fashion by the majority of dentists involved in this
field. Apart medications (muscle relaxants, non
steroidal
anti-inflammatory
drugs-NSAIDs-),
physiotherapy, ultrasound, acupuncture, electrotherapy,
night guards for bruxers and eradication of oxidative
stress1 (Kawai, Lee, Kubota, 2008) have been
advocated. The use of occlusal adjustment7 is no longer
accepted as a modality to treat TMDs and anterior
repositioning splints no longer used for the treatment of
articular problems, being replaced by stabilization
splints.
Internal derangements are classified as acute and
chronic and a decision is made if the disk can be
reduced (brought back to its functional position) or
not. Mouth appliances are often used to change
mandibular position. Splints6 (orthotics) of many
various types are worn 24 hours/day (one for day use
39
Tabbara N
and another for night use) for a period of 4-6 months.
Once the disc is reduced and stabilized, a permanent
change in the occlusion is often indicated, thus
allowing the disc to be maintained in that position.
This is achieved with orthodontics16,17, complete oral
restorations, or overdentures. Surgery is only indicated
in rare situations when anatomical modifications have
been severe and when symptoms persist. It is
important to keep in mind that in instances where the
disc has been displaced for over a year, the success in
repositioning is limited. In such cases, unloading the
joints may allow for the formation of a pseudo-disc,
which can improve function and decrease symptoms.
The alternate school of thought relies almost
exclusively on the history and clinical examination to
conclude whether there is a TMD and to recommend
treatment. It gives little value for study models,
radiographs and mandibular condyle position and does
not rely on jaw tracking, joint vibration analysis, or
electromyography. Once systemic causes1,9 (arthritis,
oxidative stress,...) are ruled out, physiotherapy,
medication, patient education and exercises are the
most commonly accepted treatment modalities. In
some cases, night guards are indicated to decrease
excessive loading when patients cannot control it.
Changing the mandibular position is not
recommended. Surgery is the treatment of last resort.
Multiple courses are available for the dentist to be
proficient in managing these patients, whether for the
TMJ pathology per se or to relieve patients from head,
neck and facial pain. When treatment includes
permanent changes of the occlusion, dentist may
follow up with orthodontic treatment or oral
rehabilitation.
CONCLUSION2,8,13,19
As the scientific literature on this topic continues to
expand, so does the potential for dental practitioners to
greatly benefit their patients in truly remarkable ways.
Although patients do not commonly discuss their
headaches and related symptoms with dental
practitioners, we should thoroughly question them in
order to identify ways in which we can help.
Treating TMDs has helped and continues to help
millions of people manage or eliminate migraines,
tension-type headaches, stiff necks, all while offering
40
them improved jaw function. We have reached a very
exciting point in the development of this field and with
the the advent of new insights from both practitioners
and basic researchers, we will certainly continue to
advance our diagnostic and therapeutic capabilities .
REFERENCES.
1- Kawai Y, Lee M-C, Kubota E. Oxidative stress and
temporomandibular join disorders.Jap Dent Sc Rev
2008;44:145-150.
2- Turp JC, Greene CS, Strub JR. Dental occlusion:a critical
reflection on past ,present and future concepts. J Oral Rehab
2008;35:446-453.
3- Browne PA, Clark GT, Yang Q, Nakano M.
Sternocleidomastoid muscle inhibition induction by
trigeminal stimulation. J Dent Educ 1993;72:1503-1508.
4- Byrd KE, Stein ST. Effects of lesions to the trigeminal motor
nucleus on temporomandibular disc morphology. J Oral
Rehabil 1990;17:529-540.
5- Clark GT, Browne PA, Nakano M, Yang Q. Co-activation of
sternocleidomastoid muscles during maximum clenching. J
Dent Res 1993;72:1499-1502.
6- Stiesch-Scholz M,Kempert J,Wolter S,Tschernitschek
H,Rossbach A.Comparative prospective study on splint
therapy of anterior disc displacement without reduction.J
Oral Rehabil 2005;32:474-479.
7- De Boever JA, Carlsson GE, Klineberg IJ. Need for occlusal
therapy and prosthodontic treatment in the management of
temporomandibular disorders. Part I. Occlusal interferences
and occlusal adjustment. J Oral Rehabil 2000;27:367-369.
8- De Leeuw R. Orofacial Pain. Guidelines for Assessment,
Diagnosis, and Management, ed 4. Chicago: Quintessence,
2008.
9- Dijkgraaf LC, De Bont LGM, Boering G, Liem RS. The
structure, biochemistry, and metabolism of osteoarthritic
cartilage: A review of the literature. J Oral Maxillofac Surg
1995;53:1182-1192.
10- Dijkgraaf LC, De Bont LGM, Boering G, Liem RS. Normal
cartilage structure, biochemistry, and metabolism: A review
of the literature. J Oral Maxillofac Surg 1995;53:924-929.
11- Eversole LR, Stone CE, Matheson D, Kaplan H.
Psychometric profiles and facial pain. Oral Surg Oral Med
Oral Pathol 1985;60:269-274.
12- Flor H, Birbaumer N, Schulte W, Roos R. Stress related
electromyographic responses in patients with chronic
temporomandibular pain. Pain 1991;46:145-182.
13- Friction JR, Kroening RJ, Hathaway KM (eds). TM
Disorders and Craniofacial Pain: Diagnosis and
Management. St Louis: Ishiaku Euro America, 1988.
14- Hagberg C, Hellsing G, Hagberg M. Perception of
Volume 46 - Nº 1 - 2009
Tabbara N
cutaneous electrical stimulation in patients with
craniomandibular disorders. J Craniomandib Disord Facial
Oral Pain 1990;4:120-125.
15- Hu JW, Yu XM, Vernon H, Sessle BJ. Excitatory effects on
the neck and jaw muscle activity of inflammatory irritant
applied to cervical paraspinal tissues. Pain 1993;55:243250.
16- Henrikson T, Nilner M. Temporomandibular disorders,
occlusion, and orthodontic treatment. J Orthod
2003;30:129-137.
17- McNamara J,Seligman D,Okesson J. Occlusion,orthodontic
treatment,and TMD: a review. J Orofacial Pain 1995;9:7389.
18- McNeill C. Craniomandibular (TMJ) disorders-The state of
the art. Part II. Accepted diagnosis and treatment
modalities. J Prosthet Dent 1983;49:393-397.
19- McNeill C, Danzig WM, Farrar WB et al. Craniomandibular
(TMJ) disorders-The state of the art. Position Paper of the
American Academy of Craniomandibular Disorders. J
Prosthet Dent 1980;44:434-437.
20- Pullinger A, Seligman DA. Quantification and validation of
predictive
values
of
occlusal
variables
in
temporomandibular disorders using a multifactorial
analysis. J Prosthet Dent 2000;83:66-75.
21- Reid KI, Gracely RH, Dubner RA. The influence of time,
facial side, and location on pain-pressure thresholds in
chronic myogenous temporomandibular disorder. J Orofac
Pain 1994;8:258-265.
22- Rugh JD, Solberg W. Psychological implications in
temporomandibular pain and dysfunction. In: Zarb Function
and Dysfunction. Copenhagen: Munksgaard, 1979:239258.
23- Seligman DA, Pullinger A. Analysis of occlusal variables,
dental attrition, and age for distinguishing healthy controls
from
female
patients
with
intra-capsular
temporomandibular disorders. J Prosthet Dent 2000;83:7682.
24- Southwell J, Deary IJ, Geissler P. Personality and anxiety in
temporomandibular joint syndrome patients. J Oral Rehabil
1990;17:239-243.
Correspond with:
Nabil Tabbara
[email protected]
Author’s website:
www.drtabbara.com
Journal of the Lebanese Dental Association
41
Esthetic Dentistry
Porcelain veneers as an esthetic restorative strategy for the
treatment of stained anterior teeth: a clinical report.
Karim Corbani*, Dr. Chir. Dent. , DES (Endo. ), FAACD
A bst ract
Porcelain laminate veneers have become a treatment of choice in solving many esthetical and functional dental problems.
Fluorosis, in some forms,causes teeth discoloration that can affect patients’ esthetic and create psychological distress. This
clinical report describes treatment sequences in a patient diagnosed with fluorosis on maxillary and mandibular teeth. The
patient’s functional and esthetic expectations were successfully met with a proper strategy and knowledge of the used material.
INTRODUCTION
A challenge facing dental clinicians is the
achievement of an optimal long-term esthetic result,
mainly in the restoration of healthy anterior teeth with
dental discoloration1.
Tooth discoloration may be classified as intrinsic,
extrinsic and a combination of both.2 Intrinsic
discoloration occurs following a change to structural
composition or thickness of dental hard tissues.
Ageing,
enamel
microcracks,
tetracycline
administration, dental restorative materials, caries and
fluorosis cause intrinsic tooth discoloration.3,4
Excessive fluoride ingestion(more than 1 to 2 ppm)
can cause metabolic alteration in
ameloblasts,
resulting in a defective matrix and improper teeth
An
affected
tooth
shows
calcification5.
hypomineralized , porous subsurface enamel and acidresistant well-mineralized surface layer.
There is evidence to suggest that prevalence of
dental fluorosis has increased over the past decades.
This indicates that in
populations consuming
fluoridated and nonfluoridared water, water supply
may be affected by other sources of fluorides, such as
exposure to higher intake of fluorides from foods and
soft drinks6 or the use of fluoridated toothpastes and
supplements7.
Bleaching or microabrasion is often ineffective or
gives transient results,8,9 while composite resin
* Senior Lecturer,Department of Restorative and Esthetic
Dentistry,Saint-Joseph University Faculty of Dental
Medicine,Beirut,Lebanon.
Journal of the Lebanese Dental Association
Volume 46 - Nº 1 - 2009
laminate veneers not only discolor and wear with time,
but quite often become chipped or debonded.10
It is recommended that a conservative treatment be
used wherever possible as an alternative to other
options that may sacrifice tooth structures. Porcelain
laminate veneers (PLV) has been proposed as the
treatment of choice, especially when tooth alteration
or modification of alignment is required.11 Although
porcelain veneer has displayed good longevity in
clinical studies,12-15 achieving a successful outcome
can be challenging in patients with insufficient enamel
for bonding to occur, caries, parafunctional habits and
periodontitis.
Clinicians must consider multidisciplinary approach
for complex cases, provide treatment in the correct
sequence, ensuring that the outcome will meet
patient’s functional and esthetic expectations.16
The understanding of behavior and properties of
the materials used as for the PLV and luting agent, in
combination with the clinical steps, is crucial for the
final outcome.
CASE REPORT
A 34-year-old man presented to our clinic
complaining of unpleasant smile due to generalized
teeth discoloration and the presence of gaps between
his maxillary anterior teeth (Fig.1). His medical
condition was non-contributory.
Diagnosis and treatment planning
The patient had a generalized enamel fluorosis
affecting all his permanent teeth (Fig.1), confluent
43
Corbani K
Fig. 1: Generalized enamel
fluorosis affecting all permanent
teeth
Fig. 2: Compromised patient’s smile line
pitting was present on most maxillary teeth surfaces,
with wide spread of yellow-brown stains. Mandibular
anterior teeth were relatively less affected than others.
Incisal and occlusal surfaces of maxillary incisors and
premolars were worn out due to loss of enamel
structure as a result of post-eruptive trauma (Fig.2)
affecting patient’s smile line. He also sustained a midline diastema of 2mm. Occlusion was in Class-I
relationship. Oral hygiene was good except in anterior
mandible, with a slight marginal gingivitis. Peri-apical
and bite-wing radiographs showed no caries or
alveolar bone loss.
After possible treatment modalities were discussed
with the patient, decision was made to construct 14
PLV on maxillary teeth # 17 to # 27 and on mandibular
teeth #37 to # 47. Regarding mandibular anterior teeth,
patient was advised to undergo generalized scaling.
Treatment sequences
The procedure was carried out in four phases1,17.
Phase I: Smile analysis, preliminary shade selection
(Vitapan, 3D Master, Vita, Zahnfabrik), photographs
and study models to evaluate the occlusion and make a
diagnostic wax up.
Phase II: Preparation for PLV (must be uniform and
whenever possible, totally restricted to enamel).
However, reduction of tooth buccal surface will
44
Fig.3a: Different aspects of mandibular teeth preparations
for PLV
depend on severity of discoloration, position of tooth
and the amount of enamel loss. This goal was attained
in the present patient by means of calibrated spherical
diamond burs (#1012, KG Sorensen) at the cervical
region and burs with a depth-limiting device (LVS1Laminate Veneer System, Komet-Brasseler) at tooth
Volume 46 - Nº 1 - 2009
Corbani K
Fig.4: The new smile line
Fig. 5: Final result
Fig.3b: Different aspects of maxillary teeth preparations
for PLV
buccal surface. The remaining facial enamel was
reduced to the level of these grooves with a taperedcylinder, round-end diamond bur (#2135, KG
Sorensen); the uniform reduction was about 0.4mm.
Incisal edge was reduced by 2mm and finished as a
butt joint. To completely mask teeth, additional
attention was given to proximal areas, where limit was
placed beyond interdental contact (Figs.3a and 3b).
The final impression was taken by placing a
retraction cord (Ultrapak # 0, Ultradent, USA) in the
gingival sulcus, and a complete impression was made
using a polyvinyl siloxane material (Virtual, IvoclarVivadent, Schaan, Liechtenstein). A final shade
selection was made (Vitapan, 3D Master, Vita,
Zahnfabrik, Germany) and photographs taken. Finally,
provisional
restorations
(Integrity,
Dentsply,
Germany) were placed and cemented (Systemp.cem,
Ivoaclar-Vivadent). Maxillary and mandibular
impressions were sent to the dental technician for
pouring, making of dies and fabrication of PLV using
a heat-pressed ceramic system (IPS Empress Esthetic,
Ivoclar-Vivadent).
Phase III: Veneers were sent by the technician and
Journal of the Lebanese Dental Association
carefully positioned on the master cast and intraorally
to verify the fit, marginal adaptation, shape and color.
Luting procedures were started after isolating gingiva
with a rubber dam (OptraGate, Ivoclar-Vivadent). A
try-in paste was used to determine the appropriate
cement shade (HV+3,Variolink Veneer, IvoclarVivadent); then the fitting surface of the restorations
were etched with 9.5% hydrofluoric acid (Porcelain
Etchant, Bisco, USA) for 1 minute, washed under
running water and air-dried, and a silane agent
(Monobond-S, Ivoclar-Vivadent) was then applied and
dried after 60 seconds. The prepared tooth surfaces
were then cleaned with sodium bicarbonate jets and
rinsed with air-water spray and air-dried. Cementation
was performed using light-cured resin cement
(Variolink Veneer, Ivoclar-Vivadent), following
manufacturer’s instructions. Excess cement was
removed with a brush and the veneer restoration lightcured for 10 seconds using a halogen light (Astralis 10,
Ivoclar-Vivadent). Resin cement residues were
removed and the veneer was once more light-cured for
40 seconds at buccal and palatal sides.
Phase IV: Final finishing and polishing after 24
hours and end-treatment photographs.
45
Corbani K
Treatment outcome
Patient was satisfied with treatment outcome (Figs.
4,5) and scheduled annual follow-up visits and oral
hygiene care.
DISCUSSION
Nowadays, porcelain veneers are routinely used to
treat unesthetic anterior teeth. Despite great advances
in current ceramic systems, some difficulties persist,
such as in masking of teeth extremely discolored by
endodontic treatment or tetracycline1. The final color
exhibited by a porcelain veneer will be the resulting
interaction of three colors: the porcelain laminate, the
substrate and the luting cement. Studies showed 18,19
that the effect of porcelain translucency and thickness
influenced final esthetic result since the use of opaque
ceramic material might be more of a problem than a
solution as they cut down light transmission.20
Ideally, a porcelain veneer can completely mask
the underlying discolored tooth substance with
minimal reduction of sound tooth substance (0.3-0.7
mm for buccal surface and 0.5-1.0 mm for incisal
edge). Clinicians need to assess patients’
understanding of their dental problems and whether
they have unrealistic expectations. Patients need to
realize that severity of tooth discoloration, optical
properties of a porcelain veneer system and luting
agent can influence final results16, so it is helpful to
test the restoration with a try-in paste before final
cementation.
Acknowledgements
The author would like to gratefully acknowledge
the help of Assistant Professor Ziad Salameh for
providing expertise and support to this manuscript.
REFERENCES
1- Filho MA, Vieira CCL, Baratieri LN, Lopes GC. Porcelain
veneers as an alternative for the esthetic treatment of
stained anterior teeth: clinical report. Quintessence Int
2005;36:191-196.
2- Hattab FN, Qudeimat MA, al-Rimawi HS. Dental
discoloration:
an
overview.
J
Esthet
Dent.
1999;11:291–310.
3- Watts A, Addy M. Tooth discolouration and staining: a
review of the literature. Br Dent J. 2001;190:309–315.
4- Awliya WY, Akpata ES. Effect of fluorosis on shear bond
strength of glass ionomer-based restorative materials to
46
dentin. J Prosthet Dent. 1999;81:290–294.
5- Haywood VB, Berry TG. Natural tooth bleaching. In:
Summitt JB, Rabbins JW, Schwartz RS, editors.
Fundamentals of operative dentistry: a contemporary
approach. Chicago: Quintessence Publishing Co Inc; 2001.
p. 402.
6- Pang DTV, Philips CL, Bawden JW. Fluoride intake from
beverage consumption in a sample of North Carolina
children. J Dent Res 1992;71:1382.
7- Osuji OO, Leak JL, Chipman ML, Nikifourk G, Locker D,
Levine N. Risk factors for dental fluorosis in fluoridated
community. J Dent Res 1988;67:1488.
8- Goldstein CE, Goldstein RE, Freiman RA, Garber DA.
Bleaching vital teeth: state of the art. Quintessence Int
1989;20:729-737.
9- Train TE, Whorter AG. Examination of esthetic
improvement
and
surface
alteration
following
microabrasion in fluorotic human incisors in vivo.
Pediatric Dent 1996;18:353-62.
10- Walls AW, Murray JJ, McCabe JF. Composite laminate
veneers: A clinical study. J Oral Rehabil 1988;15:439-454.
11- Jun SK, Wilson S. Restoration of severely discolored
maxillary anterior teeth with porcelain laminate veneers.
Pract Proced Aesthet Dent 2008;20:285-287.
12- Dunne SM, Millar BJ. A longitudinal study of the clinical
performance of porcelain veneers. Br Dent J 1993;175:317321.
13- Miyajima K, Shirakawa K, Senda A. Application of
porcelain veneers following orthodontic treatment. J Can
Dent Assoc 1993;59:167-170.
14- Touati B. Bonded ceramic restorations: achieving
predictability. Pract Periodontics Aesthet Dent 1995;7:3337.
15- Smales RJ, Etemadi S. Long-term survival of porcelain
laminate veneers using two preparation designs: a
retrospective study. Int J Prosthodont 2004;17:323-326.
16- Chu FCS. Clinical considerations in managing severe tooth
discoloration with porcelain veneers. JADA 2009;140:442446.
17- Al Jazairy YH. Management of fluorosed teeth using
porcelain laminate veneers. A six-year recall case report.
Saudi Dent J 2001;13:106-111.
18- Yaman P, Qazi RS, Dennison JB, Razoog ME. Effect of
adding opaque porcelain on the final color of porcelain
laminates. J Prosthet Dent 1997;77:136-140.
19- Johansen R, Schlobohm C, Mullick S. Colorometric
analysis of porcelain veneer shade variance by composite
cements (abstract#956). J Dent Res 1991;70 (special
issue):385.
20- Masterdomini D, Friedman MJ. The contact lens effect:
Enhancing porcelain veneers esthetics. J Esthet Dent
1995;7:99-103.
Correspond with:
Karim Corbani
[email protected]
Volume 46 - Nº 1 - 2009
Removable Prosthodontics
You do not have to be an FBI agent to find and register the
retruded contact position in the treatment of the prosthodontic
patient.
Tony Daher1, Dr. Chir. Dent. , CES Prostho. , M. S . Ed. , FACP , FICP, Dipl. ABP, Joseph J. Massad2, DDS ,
FACD, FICD
A bst ract
Many definitions and techniques are available, describing and registering centric relation or occlusion. This paper is a brief
review of dental literature regarding centric relation (CR), depicting four categories of CR recording: direct interocclusal records,
intraoral and extraoral graphic recordings, functional recordings and cephalometrics.
Our study proposes the use of the terms Retruded Contact Position (RCP) instead of Centric Relation or Centric Occlusion.
RCP is defined as retruded, unstrained, repeatable position where mandibular movements start. With this definition, it is easy
to select a technique that meets all requirements of such position.
A new and improved Jaw Recorder, designed by J. Massad, is presented here. This jaw recorder is an intraoral graphic recording
device that results in a tracing of mandibular movements in one plane, with the apex of tracing indicating the most retruded
relationship. The intersection of arches produced by right and left working movements forms the apex of what is known as
Gothic arch tracing.
Clinical situations using jaw recorder are described, and clinicians can now, quickly, easily and accurately record RCP, balance
complete, partial or implant dentures and orthopedically reposition mandible. This has many advantages and results sound more
reliable and reproducible than many traditional manipulation techniques.
Complete mouth rehabilitation of any clinical
situation starts with a complete analysis of the total
oral environment1 by seeking to establish an optimum
plane of occlusion, occlusal vertical dimension,
occlusal scheme and esthetics for a proper prosthetic
restoration1,2.
To do so, one must depend on an adequate
collection of prosthodontic data that includes personal,
medical, dental and prosthetic histories, necessary
radiographs, articulated dental casts and visual and
digital extraoral and intraoral clinical examinations.1
Most practicing dentists very often underestimate the
practical usefulness of articulated dental casts. This
results in unforeseen future treatment problems and
poor outcomes. These preliminary study casts are
articulated at the correct therapeutic occlusal vertical
dimension in a retruded contact position, on a semi1 Associate Professor, Department of Restorative Dentistry,
Loma Linda University School of Dentistry, California,
US A,
2 Adjunct Professor, Tufts University, Boston, USA, and
Director of Removable Prosthodontics, Scottsdale Center
for Dentistry, Arizona, US A,
1,2 The Massad Group, Tulsa, Oklahoma, USA.
Journal of the Lebanese Dental Association
Volume 46 - Nº 1 - 2009
adjustable articulator using an adjusted ear-facebow
and often a protrusive record.1
Occlusal surfaces harmony between any type of
prostheses and remaining natural teeth is an important
factor in the preservation of surrounding oral tissues.
One of the final goals in complete edentulous
mouth treatment is to establish a satisfactory
articulation. This is done by evaluating the existing
occlusal scheme, correcting the existing occlusal
disharmony, recording a retruded physiologic jaw
position,
recording eccentric jaw relations and
correcting occlusal discrepancies created by the fit of
final prosthesis.
Many occlusal schemes are described in dental
literature and practiced every day. There is no
scientific evidence that supports one occlusal scheme
rather than another.3 Where anterior guidance must be
reestablished or where it changes, there currently
appears to be more authorities that favor canine
guidance over group function.3 For complete dentures,
most prosthodontists are using a balanced type of
occlusal scheme where the location of centric relation
or retruded contact jaw position is an important step
for the application of any occlusal scheme.
47
Daher T, Massaad JJ
The purpose of this paper is to present a predictable
and easy way to locate and register a centric or
retruded and eccentric physiologic jaw positions.
movement formed the apex of what is known as the
Gothic arch tracing (Fig.1).
LITERATURE REvIEW
Literature on centric relation is vast, and definition
and methods of attaining and recording centric relation
have always been controversial. Glossary of
Prosthodontic terms, published every 6 years by the
Academy of Prosthodontics, has changed the definition
of centric relation often. The 2005 edition of this
publication4 has 7 definitions for centric relation.
Centric relation is defined as “the maxillomandibular
relationship in which the condyles articulate with the
thinnest avascular portion of their respective disks with
the complex in the anterior-superior position against
the shapes of the articular eminencies. This position is
independent of tooth contact and clinically discernible
when the mandible is directed superiorly and anteriorly.
It is restricted to a purely rotary movement around the
transverse horizontal axis”.4
In addition, Jasinevicius and co-workers5 found out
in their study on the definitions of centric relation,
taught in seven US dental schools, that there was no
consensual definition.
Centric relation (CR) concept has undergone
constant debate and revision and “Most authors agree
that CR record is the most important and most difficult
maxillomandibular relation record to make.”6 For this
reason, many methods for recording centric relation
records have been suggested in the literature.
Categories of CR recording are as follows:
m
1. Direct interocclusal records,
2. Intraoral and extraoral graphic recordings,
3. Functional recordings,
4. Cephalometrics.7
1- The direct interocclusal recording was described
in the 1700’s by P. Pfaff, known as the “mush-squash”
or “bisquit” bite. Hanau and Wright improved the
technique in the 19th Century.
2- Graphic recording methods result in a tracing of
mandibular movements in one plane, with the apex of
the tracing indicating the most retruded relationship.
They can be made intraorally or extraorally, depending
on where the records are placed. The intersection of
the arches produced by right and left working
48
Fig. 1. Gothic arch tracing on a disposable flat plastic
striker on a maxillary arch and the opposing pin and pin
receiver plate on the mandibular arch.
The earliest graphic tracings were made by
Balkwill in 1866, then improved by Hess, Gysi and
Sears around 1925. Stansberry introduced it in 1929
and Hall later modified it, using a central bearing
screw to help equalize the pressure on the supporting
structure. Phillips developed a tripoded ball bearing,
mounted on a jackscrew for the mandibular occlusion
rim. It was called “central bearing point”.
3- Functional recordings or “chew-in” records were
first described in 1910. Needles used studs mounted on
record bases to engrave arrow tracings into compound
rims in the mandibular arch.
Boos developed the gnatho-dynamometer to
determine where maximum biting force could be. He
claimed that optimum occlusal position and position of
maximum biting force are coincident.
4- Cephalometric recordings of CR were performed
by Pyott and Schaeffer in 1952 to determine CR and
the appropriate vertical dimension of occlusion using
radiographs. Due to excessive patient’s exposure to
radiation, this practice was not popular.
Techniques for CR recording have evolved,
resulting from improvements and modifications of old
CR records techniques.
Schweitzer stated that most experienced dentists
may not be able to give a precise definition of this
controversial position, but for the average patient
whom they treat, they were able to record it.8
This is due to various factors which influence
recording of CR including: pain in TMJ or masticatory
system, protective reflexes caused by faulty occlusal
contacts, emotional stress, recording media, guidance
Volume 46 - Nº 1 - 2009
Daher T, Massaad JJ
or manipulation by the clinician and neuromuscular
conditioning.7
In teaching prosthodontics and when we describe
any CR recording technique, it is very hard to
convince any clinician or dental student that the
technique will put mandibular condyles to articulate
with the thinnest avascular portion of their respective
disks with the complex in the anterior-superior
position against the shapes of articular eminencies.
This might be feasible if we have radiographic vision.
In addition, it has been argued that anterior disc
position is a variant of normal disc position and it has
been challenged: “…not all discs displaced are
associated with derangement or other joints pathosis”.9
“…50% of the condyles do not seat”10.
We propose the use of the terms Retruded Contact
Position (RCP) instead of Centric Relation or Centric
Occlusion. RCP is defined as retruded, unstrained,
repeatable position and where mandibular movements
start. With this definition, it is easy to select a technique
that meets all requirements of such position. As we
know, repeatability remains number one of most
suitable and accepted methods for evaluating a
mandibular record to be used for the articulation of a
dental cast, denture fabrication and occlusal
equilibration. If a mandibular record is not reproducible,
dentists cannot evaluate treatment outcomes. Celenza11
once stated: “The precision of the position may be more
important than the position itself”.
For all above reasons,we have selected the use of
Gothic arch tracings made by a central bearing device
for the determination of such mandibular jaw position.
The central bearing device has a long history in
dentistry. Due to the many devices available over the
years, some confusion and misuse have resulted.
However, with recent developments and refinements, it
is suggested that dentistry revisits in light of this
concept, that more than one use is applicable. Use of a
central bearing device during maxillary-mandibular
record making for edentulous patients has been debated
in great detail over the years. However, immediate
denture record using the jaw recorder (Fig. 2) facilitates
the obtention of a physiological retruded contact
position. When used during complete denture therapy,
it is generally believed that central bearing device
provides equalization of occlusal pressure and
increases record base stability when denture-bearing
Journal of the Lebanese Dental Association
mucosal resiliency is modest. Additionally, when the
bearing plate is inked prior to placement, unguided
mandibular movements through all eccentric positions
will result in a Gothic arch tracing by the central
bearing point on the bearing or striking plate. The apex
of this tracing may then be used to identify centric
relation position, right and left excursions and
protrusion along the borders of the tracing. A thin
plastic pin receiver plate single perforation or a divot
prepared with a round bur into the bearing plate can be
used to let the patient hold this position at the apex
while registration material is being placed. This Gothic
arch tracing method and maxillary-mandibular
registration technique is considered highly reliable,
even for inexperienced clinicians, if used at a given
vertical dimension12. In dentate or partially edentulous
patients or patients with implants supporting a
removable prosthesis, this method increases reliability
of record by not allowing any tooth contact which may
deflect mandibular movements.
Advantages of such record are many:
1) its repeatability,
2) with the use of a flat platform, reflex pattern of
closure or engram will be forgotten,
3) apex of the tracings is easy to identify and
represents the retruded contact jaw position,
4) its use in different clinical situations and stages
in prosthesis fabrication: for example during RCP
recording and placement of prosthesis to correct some
occlusal discrepancies or to do a clinical remount.
DESCRIPTION OF THE TECHNIqUES
ACCORDING TO SOME CLINICAL
SITUATIONS.
Record a patient’s Retruded Contact Position
(RCP):
An accurate repeatable RCP record can be made
quickly and easily with the Jaw Recorder (Fig. 2)
(LeeMark Dental). Successful identification of centric
position results in fewer appointments to removable
and fixed cases and less occlusal adjustments required
at delivery of case.
Record PRP: In order to find patient’s correct
RCP, we must first accurately record Physiologic Rest
Position (PRP), commonly known as “resting
position”. This is the position we most often find
49
Daher T, Massaad JJ
ourselves with teeth slightly apart during rest.
Recording this measurement usually involves five
simple steps: (1) place a dot for reference on patient’s
nose and chin, (2) coach the patient to his/her unique
relaxed position, (3) adjust each leg of a caliper to the
edge of each dot, (4) lock the caliper opening and
transfer measurement to paper, (5) adjust the pin on the
Jaw Recorder to touch the maxillary striking plate at
this measurement.
Adjust to OvD: By definition, Occlusal Vertical
Dimension (OVD) is 1-4 mm less than measured PRP.
After recording PRP and adjusting the pin to the
striking plate at PRP, the pin on the Jaw Recorder is
then adjusted to decrease the relationship to the
maxillary striking plate 1-4 mm, stabilizing the
patient’s jaws at this critical vertical position. The
patient is then directed through anterior-posterior and
retruded lateral movements. The resulting path of
contact between pin and striking plate traces the
classic “arrow” portion of a Gothic arch tracing. The
point of contact between pin and plate at the point or
tip of the arrow represents patient’s unique RCP and
can be locked and stabilized with a bite registration
material for accurate transfer to an articulator.
Balance Complete Dentures, Partial Dentures, and
Implant Dentures (Figs. 2 to 20)
One of the most difficult procedures in removable
prosthodontics is finely equilibrating the occlusion of
the finished prosthesis. Intra-orally, prosthesis moves
with every occlusal prematurity, producing erroneous
marks with the articulating paper. Extra-oral remounts
2a
2b
often incorporate inaccuracies, due to the remount
procedure itself! The Jaw Recorder eliminates these
problems.
When mounted on the finished prostheses, pin and
striking plate of the Jaw Recorder perform two
functions. First, they act as a central bearing point,
stabilizing the prostheses through constant, centralized
pressure. Second, the pin can be adjusted until teeth
are slightly apart, and then slowly closed. Through this
gradual closure, the smallest occlusal prematurity can
be noticed and appropriately adjusted. This process is
continued until occlusion is adequate and equal on
both sides of the arch.
Orthopedically reposition the mandible
Many times, a denture patient will present a
severely over-closed jaw position. It is important to
return facial musculature to proper vertical position
prior to final RCP Recording. Muscles programmed to
an improper occlusion will make difficult, both centric
recording and patient’s ability to adapt to the new
prosthesis. Fabrication of an accurate occlusal splint
will accomplish these goals. Splint therapy can be
simple with the Jaw Recorder.
Jaw Recorder is mounted on patient’s current
prostheses (or duplicates of them). The pin/striking
plate relationship is adjusted, until patient’s jaws are
held at desired OVD. An acrylic resin is then placed
over mandibular posterior quadrants and maxillary
posterior teeth are lubricated. While acrylic is in a
“doughy” consistency, patient is instructed to
continuously “rub” the pin against the plate in all
directions until acrylic sets. After curing and
2c
Figs. 2a, 2b, 2c.: a) “Massad Jaw recorder” is secured in place onto maxillary and mandibular complete dentures at the new
proposed OVD. b) Auto polymerizing acrylic resin is added to mandibular occlusal surfaces. While in putty stage, patient is
asked to make eccentric movements till its final set. c) Dentures are removed from mouth and the added resin is shaped to normal
contour. Then, remove Jaw Recorder device and polish prostheses.
50
Volume 46 - Nº 1 - 2009
mouth and the added resin
t
Daher T, Massaad JJ
6a
6b
Figs. 6a, 6b. a) Mandibular restorations reveal decay and
fractured teeth #20 and #24 are non restorable. b) Mandibular
definitive cast giving detail necessary for final prosthesis.
Fig. 3. The “Massad Disposable Tracers” (Jaw Relation
Recording Device designed by Joseph J. Massad).
trimming, a patient-generated splint has been
fabricated at the correct OVD. Patient can wear this
splint during denture fabrication, allowing muscles to
de-program.13
1- Technique for Immediate Complete Denture
Situation:
Fig. 4. Dots are placed on nose and chin in preparation of
making a physiological resting position on a 79-year-old
patient.
5a
5b
Figs. 5a, 5b: a) Maxillary dentition showing deteriorating
restorations and decay.
b) Definitive maxillary cast utilizing thermoplastic heat
shapeable tray and the use of PVS gives detailed buccal areas
and tooth structures.
Journal of the Lebanese Dental Association
7a
7b
Figs. 7a, 7b. a) Maxillary acrylic appliance with a striking
plate mounted with an ink solution to identify centric
relation. b) Mandibular base plate holding the pin into a
rotatable nut allowing dentist to parallel with the maxillary
striking plate.
Fig. 8. Plastic receiving disc sticky waxed over the apex of
jaw recording.
Fig. 9. Casts articulation utilizing the Jaw Recording device
at selected occlusal vertical dimension.
51
Daher T, Massaad JJ
3- Technique for implant patient.
10a
10b
Figs. 10a, 10b. a) Articulated casts at final OVD reflecting
an increase in existing vertical at patient’s RCP. b) Final
articulated casts demonstrating dimension used in final
prosthesis.
Fig. 14. Maxillary and mandibular casts with and without
striking plate for implant supported and retained prostheses.
Noticed that 2 implant-impression copings are used to secure
the Jaw Recorder in place.
4- Technique for removable partial denture patient.
Fig. 11. Final prosthesis at new vertical and in RCP,
showing bilateral reverse occlusion on molars.
2- Technique for complete denture
Fig. 15: The mandibular ball bearing plate is secured with
clear Triad® acrylic material on the clear Triad® acrylic
baseplate. (Dentsply International, York, PA,USA)
Fig. 12. Jaw Recording device for the edentulous patient.
Articulated casts on articulator ready for set-up.
Fig. 16: The maxillary striking plate showing the Gothic
arc tracings secured on the clear Triad® acrylic wax-trial
denture. This disposable plate could be mounted also on the
wax-rim baseplate.
Fig. 13. Lateral view patient right and left.
52
Fig. 17: Records in RCP at a
slightly increased vertical
dimension of occlusion to
clear the path of mandibular
teeth
during
excursion
movements to trace the
Gothic arc tracings.
Volume 46 - Nº 1 - 2009
Daher T, Massaad JJ
18a
18b
18c
Figs.18a, 18b, 18c. a) Both baseplates are secured with a polyvinyl siloxane (PVS) material bite registration such as Futar D® in RCP.
b) another PVS bite registration in protrusion is made to program the articulator condylar inclination. This protrusive record is needed
to balance occlusion during denture fabrication. PVS centric record is needed to articulate casts on an articulator. c) PVS materials in a
gun delivery system.
3. Thornton LJ. Anterior guidance: Group function/canine
guidance. A literature review. J Prosth Dent 1990;64:479-482.
4. Glossary of Prosthodontic Terms.
2005;94:13-83.
J
Prosthet
Dent
5. Jasinevicius TR, Yellowitz JA, Vaughan GG, et al. Centric
relation definitions taught in 7 dental schools: Results of
faculty and student surveys. J Prosthodont 2000;9:87-94.
6. Holden JE. Centric Relation treatment position concepts and
related research. American College of Prosthodontists
publication.
7. Myers ML. Central relation records. Historical review. J
Prosthet Dent 1982;47:141-145.
19a
19b
19b
Figs. 19a, 19b. a) RCP record is trimmed before
its use in
19b
articulating casts. b) casts articulated using Gothic arch
tracing records and PVS RCP record.
8. Schweitzer JM. Dental occlusion: a pragmatic approach.
Dent Clin North Am 1969;13:687-724.
9. Stegenga B, de Bont LGM, Boering G. et al. Tissue responses
to degenerative changes in the temporomandibular joint: a
review. J Oral Maxillofac Surg 1991;49:1079-1088.
10. Scapino RP, Mills DK. Disc displacement internal
derangements. In: McNeill C. Science and Practice of
Occlusion. Quintessence Books. 1997. Chap 18.
11. Celenza FV. The centric position: replacement and
character. J Prosthet Dent 1973:30;591-598.
20a
20b
Figs. 20a, 20b. a) patient’s smile. b) final prostheses in
patient’s mouth.
REFERENCES
1. Daher T, Hall D, Goodacre CJ. Designing Successful
Removable Partial Dentures. Compendium of Continuing
Education in Dentistry 2006;27,3:104.
2. McGivney GP, Carr AB. McCracken’s Removable Partial
Prosthodontics. 7th Edition. Chap 17:355.
Journal of the Lebanese Dental Association
12. Mohamed A, El-Aramany MA, George WA, Scott RH.
Evaluation of the needle point tracing as a method for
determining
centric relation.
J
Prosthet
Dent
1965:15,1043.
13. Massad JJ, Connelly ME, Rudd KD, Cagna DR. Occlusal
device for diagnostic evaluation of maxillomandibular
relationships in edentulous patients: A clinical technique. J
Prosthet Dent 2004;91:586-590.
Correspond with:
Tony Daher
[email protected]
53
Restorative Dentistry
The use of low level laser after cavity preparation in vital tooth: a
clinical report.
Carlos de Paula Eduardo1, DDS , M. S c. , Ph. D , Rodney Garcia Rocha2, DDS , M. S c. , Ph. D , Karen Müller
Ramalho3, DDS , M. S c
A bst ract
Patients frequently complain of post-operative pain after cavity direct and indirect preparations. Restorative procedures are
obviously a source of injury to pulp tissue as a result of several factors, such as heat generated by cavity preparation, method
of restorative material placement, chemical irritants and others. Low level lasers (LLL) are reported to be analgesic,
biomodulatory and anti-inflammatory: published studies have shown their numerous effects after cavity preparation, among those
biomodulation of pulp cells, decreased inflammatory reaction in the pulp and acceleration of dentin recovery (in the pre-dentin
region). These two case reports describe and illustrate the use of LLL as a complementary tool preventing post-operative
sensitivity after cavity preparation in direct and indirect restorative procedures.
Restorative procedures are a source of pulp tissue
injury and post-operative pain, and can occur because
of several factors such as heat generated during cavity
preparation, method of restorative material placement,
chemical irritants, and others1-2. Patients regularly
report post-operative pain after cavity preparation, for
both direct and indirect restorations.
Cavity
preparation induced heat can be controlled with
adequate cooling and the use of a new bur. The older
the bur, the lower its cutting capacity; consequently,
more time is required to cut hard tissues and further
forces are needed during the restorative procedure, and
hence further heat is generated. In order to prevent
post-operative sensitivity, small pellets of composites
can be inserted in the cavity to avoid polymerization
shrinkage, and irrigants and restorative materials
should be biocompatible with prepared dental hard
tissues.
Nowadays, several new technologies are able to
1 Full Professor, S pecial Laboratory of Lasers in Dentistry
(LELO), Department of Restorative Dentistry, University
of São Paulo, School of Dentistry, São Paulo, Brazil,
2 Full Professor, Department of Stomatology, University of
São Paulo, School of Dentistry, São Paulo, Brazil,
3 Ph.D student, Department of Stomatology, University of
São Paulo, School of Dentistry, São Paulo, Brazil.
Journal of the Lebanese Dental Association
Volume 46 - Nº 1 - 2009
improve dental treatment outcome in all dental
disciplines and specialties. Low Level Laser (LLL)
technology was established as a non-invasive method
to enhance wound healing, modulate inflammatory
process and promote pain relief3-8.
The aim of the following case reports is to describe
the usefulness of LLL in preventing post-operative
pain after cavity preparation in direct and indirect
restorative procedures.
FIRST CASE REPORT
A 32-year-old woman, presented with an occlusodistal amalgam restoration on 4.5: she asked to replace
it for esthetic reasons.
After local analgesia of right inferior alveolar
nerve, rubber dam was placed and amalgam
restoration removed with dental diamond bur (No.
1046 – KG Sorensen®- Brazil) using a high speed drill
mode under copious water irrigation (Fig.1A).
After restoration removal and cavity preparation
(Fig.1B), dentin was treated with LLL- GalliumAluminum-Arsenium, GAAlAs (Compact Laser, J
Morita®, Co. Japan) with the following parameters: 30m
W power, 18 seconds/point, 790 nm wavelength (Fig.1C).
Energy density applied to the tissue was 4.15 J/cm2,
calculated according to the formula: Energy Density
57
Eduardo CDP, Garci a Rocha R, Ramal ho KM
(J/cm2)= time (s*) x laser spot size area (cm2) / power (w).
One laser beam was conveyed to the pulpal wall. Total
energy applied to the tissue was 0.54 J, according to the
formula: Energy (E) = Power (P) x time (s).
After LLL application, pulp cavity wall was protected
with a thin layer of calcium hydroxide (Dentsply®) and
dentin and enamel were then etched with 37%
phosphoric acid, followed by the adhesive step
(AdapterTM Single Bond 3M, ESPE Dental Products,
USA) in accordance with manufacturer’s instructions.
Restoration was performed with resin composite (Tetric
Ceram, Ivoclar-Vivadent, Schan, Lichtenstein).
Composite was inserted in small pellets (0.5 mm2) to
avoid polymerization shrinkage and minimize postoperative pain (Figs. 1D,E,F). Subsequently, postoperative course proved to be uneventful.
Fig. 1. First case report. A- Initial amalgam restoration. BAfter amalgam removal. C- Low Intensity Laser beam in
cavity. D- Pulpal wall protection with calcium hydroxide. ERestoration with composite resin. F- Final restoration.
SECOND CASE REPORT
A 50-year-old male patient presented with severely
decayed 2.6 and indirect restoration was planned. After
local analgesia, indirect preparation was performed
with a dental diamond bur (KG Sorensen®, Brazil)
using a high speed drill mode and under copious water
irrigation. Once the preparation was completed, LLL
therapy was performed- Gallium-AluminumArsenium, GAAlAs (Compact Laser, J Morita®,
Japan) with the following parameters: 30 mW power,
18 seconds/point, and wavelength of 790 nm (Figs.
2A,B,C). The energy density applied to dental tissues
was 4.15 J/cm2, calculated according to the formula:
Energy Density (J/cm2)= time (s) x laser spot size area
(cm2) / power (w). Three points were targeted in
occlusal dentin (Figs.2A,B,C) and total energy applied
to the tissue per session was 1.62 J, according to the
following formula: Energy (E) = Power (P) x time (s).
After laser treatment, a provisional crown was
cemented temporally. During dental preparation,
impression and final luting, LLL therapy was applied
according to the method described above. The patient
did not complain of any sensitivity and pain after
treatment.
DISCUSSION
Dentin sensitivity or hypersensitivity is common in
dental practice. Human dental pulp is highly
innervated and human teeth are classified among the
Fig. 2. Second case report. A, B, C – 3 points of low level
intensity laser beam in dentin. D- Metallic onlay. E
Metallic onlay luting. F- Final indirect restoration.
most sensitive structures12. Fearnhead13 has shown that small nerve fibrils with an approximate diameter of 0.2
µm were in close relationship with the odontoblast
process extending as far as 1.5 mm into dentin.
Moreover, Frank14, Dahl and Mjör15 studies supported
the presence of stable connections between the
odontoblast process and nerve endings in dentin.
Therefore, every stimulus applied during the
restorative procedure is captured by the pulp through
this system.
The odontoblast process continues in the form of a
large number of lateral branches16 previously seen in
predentin and dentinal tubules16. The number of tubules
was found to be 45.000/mm2, with a diameter of 2.5 µm
* s = seconds
58
Volume 46 - Nº 1 - 2009
Eduardo CDP, Garci a Rocha R, Ramal ho KM
near the pulp; whereas in middle dentin, there were
29.500/mm2 tubules with a diameter of 1.2 µm16.
Brännström and co-workers17 proved that the main
cause of dentinal pain is a rapid outward flow of fluid
in dentinal tubules, initiated by capillary forces.
Temperature was found to have a great effect on
hydraulic conductance of dentin. Increasing the
temperature by 40ºC resulted in a 1.8 fold increase in
fluid flow in unetched dentin and in a 4 fold increase
in acid-etched dentin. This increment in hydraulic
conductance was attributed to thermal expansioninduced increases in tubular diameter18. Therefore, a
high temperature increase occurring during dental
treatment will generate stimuli transmitted to pulp,
leading to post-operative sensitivity. Consequently,
dentists should take special care to prevent inducing
high temperatures in etched dentin.
LLL is absorbed by specific chromophore
photoreceptors, and once absorbed, light can modulate
cell biochemical reactions and stimulate mitochondrial
respiration9. This primary response will lead to
secondary responses such as increase in ATP synthesis,
collagen production, cell proliferation and migration
and biomodulation of inflammatory molecules10-11.
Advantages of LLL use in restorative dentistry
were reported in several in-vivo studies. Godoy and
co-workers2 used a laser with 670 nm wavelenghth, 30
mW and 2 J/cm2 parameters, applied directly and
perpendicularly in Class I cavities in premolars during
one single session, then the teeth were restored with
composite resin. After 28 days, teeth were extracted
and transmission electron microscopy-TEM- analysis
showed that lased groups displayed an odontoblast
process in greater contact with extracellular matrix. In
addition, collagen fibrils appeared more aggregated
and organized than those of the control group. It was
concluded that laser treatment accelerated recovery of
dental structures involved in cavity preparation in
predentin region.
Ferreira and co-workers19 used a 670 nm
wavelength/ 50 mW - 4 J/cm2 laser in Class V cavities
in premolars before restoring them with glass ionomer.
Teeth were extracted after 14 and 42 days. Histological
changes were observed using light microscopy: less
intense inflammatory reaction was found in the lased
group when compared with control group. Only in the
Journal of the Lebanese Dental Association
group of teeth extracted 42 days after laser application,
an area associated with reactionary dentinogenesis was
shown. Immunohistochemical analysis revealed that
expression of collagen type III, tenascin, and
fibronectin were greater in the treated group.
Inflammatory modulation capacity of LLL has been
documented in several studies4-5-20 that described
molecular basis of LLL in the inflammatory
biomodulation process, such as Prostaglandin E2
(PGE2)
inhibition
through
reduction
of
cyclooxygenase messenger RNA (COX-2 mRNA)
levels, as well as Interleukin-1 (IL-1) inhibition in a
dose dependent manner. Other studies on dental pulp,
using
histopathological
analysis,
evaluated
biomodulatory effect of LLL on pulp inflammatory
process21,22 and reparative process23.
LLL can also be beneficial in pain control:l6,24-26
Mechanism by which laser controls pain has not been
completely elucidated. It has been previously
suggested that laser has an effect on peripheral
endogenous opioid24, serotonin production25, ACTH
and ß-endorphin release. Therefore, pain caused by
rapid outward flow of fluid in dentinal tubules can
probably be controlled by LLL therapy.
All beneficial effects of LLL, such as pain control,
inflammatory and reparative tissue modulation can be
indicated in restorative procedures, enhancing pulp
tissue recovery as well as providing patients with postoperative relief.
Based on these two case reports and previously
published data, it is suggested that LLL can be
beneficial as a coadjuvant in conventional restorative
treatment. Nonetheless, dentists should always keep in
mind factors that may induce tissue damage, such as
use of old dental burs (that cause abrasion and
excessive heat during cavity preparation), restorative
material placement method and chemical irritants.
Acknowl edgements
LELO – Center of Study, Clinic and Teaching of Lasers
in Dentistry, Dental School, University of São Paulo,
Brazil; CNPq (303798/2005-0).
59
Eduardo CDP, Garci a Rocha R, Ramal ho KM
REFERENCES
1- Murray PE, About I, Lumley PJ, Franquin JC, Remusat M,
Smith AJ. Human odontoblasts cell number after dental
injury. J Dent 2000;28:277-285.
contrast, polarization, interference and bright field
microscopic observations on the lateral branch system.
Arch Oral Biol 1966;11:355-362.
17- Brännström M. Sensitivity of dentin. Oral Surg Oral Med
Oral Pathol 1966;21:517-526.
2- Godoy BM, Arana-Chavez VE, Nuñez SC, Ribeiro MS. Effects
of low Power red laser on dentine pulp interface after cavity
preparation. An ultra structural study. Archiv Oral Biol
2007;52:899-903.
18- Pashley DH, Thomson SM, Stewart FP. Dentin
Permeability: Effects of temperature on hydraulic
conductance. J Dent Res 1983;62:956-959.
3- Moore P, Ridgway TD, Higbee RG, Howard EW, Lucroy MD.
Effect of wavelength on low-intensity laser irradiationstimulated cell proliferation in-vitro. Lasers Surg Med
2005;36:8-12.
19- Ferreira AN, Silveira L, Genovese WJ, de Araújo VC, Frigo
L, de Mesquita RA, Guedes E. Effect of GAAIAs laser on
reactional dentinogenesis induction in human teeth.
Photomed Laser Surg 2006;24:358-365.
4- Sakurai Y, Yamaguchi M, Abiko Y. Inhibitory effect of low
level laser irradiation on LPS-stimulated prostaglandin E2
production and cyclooxygenase-2 in human gingival
fibroblasts. Eur J Oral Sci 2000;108:29-34.
20- Nomura K, Yamaguchi M, Abiko Y. Inhibition of
Interleukin-1B production and Gene Expression in Human
Gingival Fibroblasts by Low-energy Laser Irradiation.
Lasers Med Sci 2001;16:218-223.
5- Shimizu N, Yamaguchi M, Goseki T, Shibata Y, Takiguchi H,
Iwasawa T, Abiko Y. Inhibition of prostaglandin E2 and
interleukin 1-beta production by low-power laser irradiation
in stretched human periodontal ligament cells. J Dent Res
1995;74:1382-1388.
21- Myers TD. Lasers in dentistry. J Am Dent Assoc
1991;122:46-60.
6- Tam G. Low power laser therapy and analgesic action. J Clin
Laser Med Surg 1999;17:29-33.
22- Frentzen T, Koort HJ. Laser in Dentistry: a new
possibilities with advancing laser technology. In Dent J
1990;40: 323- 332.
7- Tuner J, Hode L. It's all in the parameters: a critical analysis
of some well-known negative studies on low-level laser
therapy. J Clin Laser Med Surg 1998;16:245-248.
23- Paschoud Y, Holz J. Effect du soft laser sur la néoformation
d’un pont dentinaire après coiffage direct de dents humaines
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microscope életronique à balayage. Rev Mens Suisse
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8- Wedlock P, Shephard RA, Little C, McBurney F. Analgesic
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nm) low-level laser enhances peripheral endogenous opioid
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9- Karu T. Primary and secondary mechanisms of action of
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60
Volume 46 - Nº 1 - 2009
Forthcoming Dental Meetings,
Exhibitions and Conventions.
Reported by Maria Saadeh and Jihad Fakhouri
MEETING
EvENT
American Dental Association (ADA)
Annual Session
European Association for
Osseointegration: 18th Annual Scientific
Meeting 1st JOR Colloquium on Oral Rehabilitation 17th Scientific International Conference of
Syrian Dental Association
37th International Expodental
5th Bahrain Dental Society Conference TMJ Bioengineering Conference
First Dental-Facial Cosmetic International
Conference
Dubai International Implant Summit
(Biology meets technology)
6th Conference of the Gulf Dental
Association
14th International Dental Congress of the
Egyptian Dental Association (Problems
Solving
solving in Dentistry)
6th International Conference on ProblemBased Learning (PBL) in Dentistry
Congress of the French Dental Association
(Association Dentaire Francaise- ADF)
Greater New York Dental Meeting São Paulo International Dental Meeting
(CIOSP)
144th Chicago Dental Society Midwinter
Meeting
39th Annual Meeting and Exhibition of the
American Association for Dental Research
(AADR)
Journal of the Lebanese Dental Association
Volume 46 - Nº 1 - 2009
LOCATION
LOCATION
Honolulu,
USA
DATES
DATES
WEBSITEWEBS ITE
2009
Sep 30- Oct 3 www.ada.org
Monaco,
Monaco Oct 1-3
www.eao.org Sienna,
Italy
Damascus,
Syria
Rome,
Italy
Manama,
Bahrain
Boulder, Colo.,
USA
Dubai,
UAE
Dubai,
UAE
Al Khubar,
KSA
Cairo,
Egypt
Oct 7-11
www.jor-net.com
Oct 14-16
www.scs-net.org
Oct 15-17
www.expodental.it
Oct 27-29
www.bahrain-dental.com
Nov 4-7
www.TMJconference.org
Nov 6-7
www.cappmea.com/aesthetic
Nov 10-12
www.diis.ae
Nov 10-12
www.sds.org.sa
Nov 11-13
www.eda-egypt.org
Hong Kong,
Nov 13-15
China
Paris,
Nov 24-28
France
New York, NY, Nov 27- Dec 2
USA
2010
São Paulo,
Jan 3 - Feb 3
Brazil
Chicago, USA Feb 26-Mar 1
Washington DC, USA
Mar 3-6
www.facdent.hku.hk/pbl
www.adfcongres.com
www.gnydm.com
www.apcd.org.br/ciosp
www.cds.com
www.dentalresearch.org
61
UAE Dental Exhibition
Congrès International de Chirurgie
Dentaire
8th International Implantology Congress of
the Alexandria Oral Implantology
Association
Pacific Dental Conference
26th Annual Scientific Session of the
American Academy of Cosmetic Dentistry
110th Annual Session of the American
Association of Orthodontists (AAO)
WID - Vienna International Dental
Exhibition
Saudi Dentistry - International Dental
Health Exhibition
Stomatology St. Petersburg- 13th
International Dental Exhibition and
Conference
32nd Asia Pacific Dental Congress
British Dental Conference and Exhibition
Spring Meeting 2010 of the European
Academy of Esthetic Dentistry
Annual Meeting of the American Academy
of Pediatric Dentistry (AAPD)
88th General Session & Exhibition of the
International Association for Dental
Research (IADR)
FDI Annual World Dental Congress
19th Annual Scientific Meeting of the
European Association for Osseointegration
19th Annual Scientific Meeting of the
AmericanAssociation
Dental Association
European
for Osseointegration
th
96 Annual Meeting of the American
Academy of Periodontology (AAP)
Trans-Tasman Endodontic Conference:
Endodontics—Continue the Learning
Annual Congress of the French Dental
Association (Association Dentaire
Francaise- ADF)
62
Dubai, UAE
Marseille,
France
Alexandria,
Egypt
Vancouver,
Canada
Grapevine,
USA
Mar 9-10
www.aeedc.com
Mar 11-13
www.adpmarseille.org
Mar 24-26
www.aoiaegypt.com
April 15-17
www.pacificdentalonline.com
Apr 27-May 1 www.aacdconference.com
Washington DC, Apr 30-May 2
USA
Vienna, May 7-8
Austria
Riyadh, May 9-12
Saudi Arabia
St. Petersburg,
May 11-13
Russia
www.aaortho.org
www.wid-dental.at
www.recexpo.com
www.primexpo.ru/dental
Colombo, Sri Lanka
Liverpool, UK
London, UK
Chicago, USA
Barcelona,
Spain
May 12-15
www.apdc2010.com
May 20-22
www.bda.org
Salvador, Brazil
Glasgow,
Scotland, UK
Orlando,
USA
Honolulu,
Hawaii
Christchurch,
New Zealand
Paris,
France
Sep 2-5
May 27-29
www.eaed.org
May 27-31
www.aapd.org
July 14-17
www.dentalresearch.org/i4a
www.fdiworldental.org
Oct 7-9
www.eao.org Oct 9-12
www.ada.org
Oct 30-Nov 2 www.perio.org
Nov 4-6
Nov 24-27
www.tteconference.com
www.adfcongres.com
Volume 46 - Nº 1 - 2009
Hazmieh - Sayyad
Phone: 05/452555
Email: [email protected]