Diagnostic
prosthesis
for
evaluating
soft
tissue
facial support
Fig. 1 Facial
esthetics are good
with the patient’s
old complete
maxillary denture.
Dr. Izchak Barzilay DDS, Cert. Prostho., MS
Dr. Effrat Habsha B.Sc., DDS, Dip. Prostho., MSc, FRCD(C)
Dr. Samuel Strauss DDS, FRCD(C)
Ms. Irene Tamblyn RDT
Introduction
The predictability of oral implant therapy has been well
documented in the scientific literature. Numerous studies have
documented favourable long term success rates of implant
supported prostheses in edentulous patients (Adell et al., 1981;
Adell et al., 1990; Lindquist et al., 1996; Zarb and Schmitt, 1996)
in partially edentulous patients (Adell et al., 1981; Adell, 1985;
Albrektsson et al., 1988; Zarb and Schmitt, 1990, 1991; Van
Steenberghe, 1989; Wyatt and Zarb, 1998) and in restoration of the
single missing tooth. Consequently, implant supported prostheses
have supplanted other preprosthetic surgical techniques,
becoming an integral and indispensable part of the dentist’s
therapeutic repertoire.
The edentulous patient who presents for a prosthodontic
assessment has the option of being restored with either a
conventional complete denture, an implant retained/supported
overdenture, or a fixed implant supported prosthesis. Patients
presenting for implant treatment must be evaluated from both a
surgical and prosthetic standpoint. Evaluation of the quality and
quantity of bone is accomplished with both clinical and
radiographic examination. There must be sufficient bone volume
to accommodate a minimum number of dental implants to
support the planned restoration.
10
A patient who has worn a conventional complete denture for
many years has accommodated to the different components of the
prosthesis. The buccal and labial flanges as well as the teeth
provide facial support while the palatal portion provides vertical
support and has a direct effect on the phonetic quality of the
patient speech. A patient’s facial esthetics must be closely assessed
before one considers any form of prosthetic treatment. This is
especially important when one considers fabrication of a fixed
prosthesis for someone who has worn a conventional complete
denture for a prolonged length of time. An in-depth assessment of
the esthetics with and without facial support provided by the
denture must be conducted. Before prescribing a fixed implant
supported prosthesis, the patient must be evaluated to determine
if the absence of a flange, which is what would be created when a
fixed implant supported prosthesis is fabricated, will compromise
facial esthetics. This article describes a diagnostic prosthesis which
aids in evaluation of soft tissue facial support. By using this
diagnostic prosthesis, the clinician can determine whether the
prosthetic teeth alone without a flange will provide sufficient facial
support or whether a fixed implant supported prosthesis is not
feasible unless adjunctive surgical procedures, such as hard or soft
tissue grafting are done.
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Case Report
A 50 year old female patient presented to
the practice with a request to replace her
complete maxillary denture with a fixed
reconstruction based on implants. She had
worn her complete denture for 25 years and
was happy with the esthetics provided with
the prosthesis but preferred to have a fixed
restoration for masticatory comfort and
convenience (Fig 1). A discussion of the
types of implant supported prostheses was
undertaken and the patient insisted on
treatment that would give her a fixed
reconstruction rather than a removable
overdenture type of prosthesis.
The patient’s vertical dimension was
acceptable at its current level and an
assessment of facial support was
undertaken. The patients current complete
denture was removed and a cursory
evaluation showed the lip to be
unsupported. This was to be expected but
an assessment needed to be made of the
support provided by the flange of the
prosthesis versus the support provided by
the teeth of the prosthesis.
The complete denture was removed
from the mouth and duplicated using a
laboratory putty based polyvinyl siloxane
impression material (Ruthinium, Dental
Maunafacturing, Italy (Rovigo)). The
polyvinyl material was then poured up in
clear autocure acrylic and trimmed to create
a duplicate of the denture (Fig 2). The
buccal flange of the new duplicated
prosthesis was then sectioned in one piece
from second premolar to second premolar
preserving the CE junction of the teeth and
their tissue emergence (Fig 3, 4a and 4b).
This cutting is best done with a vacuum
form acrylic cutter (H219A 023 Brasseler
Inc., Savannah, GA) The tooth portion of
the prosthesis was lubricated with
petroleum jelly and repositioned on the
silicone model. The flange portion of the
duplicated prosthesis was then rebuilt with
autocure clear acrylic to reline the cut edge.
In this way both pieces are keyed into each
other without any discrepancy.
The duplicated prosthesis could now be
tried in with and without the buccal flange
to give an indication of the effect of not
having a buccal flange on a new
prosthesis. When the prosthesis was tried
in without the flange portion, lip support
was lacking (Fig 5a and 5b). By adding the
flange portion, lip support improved the
overall esthetics (Fig 6a and 6b). Based on
these two try-in procedures the patient
obviously needed lip support from an
esthetic point of view. If a fixed
reconstruction was to be planned for (as
per the patient’s wishes), lip support
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Fig. 2 The patient’s complete maxillary denture has
been duplicated in clear polymethylmethacrylate and
can be compared with the original prosthesis.
Fig. 3 The flange portion of the prosthesis has been
sectioned away from the remainder of the prosthesis
and relined to fit accurately when the pieces need to
be assembled.
Fig. 4a The lower portion of the prosthesis is used
evaluate soft tissue support of the lower portion of the
upper lip.
Fig. 4b The flange portion of the prosthesis is used to
evaluate soft tissue support of the upper portion of the
upper lip (the subnasal area).
Fig. 5a The lower portion of the prosthesis is
positioned intraorally. One can see the position of the
future teeth without the effect of the flange.
Fig. 5b Lateral view of the patient’s profile shows a
lack of support in the subnasal area.
Fig. 6a Anterior view of the assembled prosthesis
showing both portions (flange and teeth) in place.
Fig. 6b Lateral view of the partient’s profile shows
good support for the lip in both the subnasal area as
well as in the lower portion of the upper lip.
would be needed in addition to the fixed
prosthesis.
Radiographic
evidence
suggested that bilateral sinus grafts would
also be needed for implant support and
since an autogenous bone graft was being
planned, additional bone was also to be
grafted to the buccal surface of the
anterior maxillary edentulous ridge. The
tooth portion of the duplicated prosthesis
would serve as a guide to position
implants while the flange portion of the
prosthesis would serve as a guide to the
amount of bone needed to augment lip
support.
The patient underwent two surgical
procedures. The first was a bone grafting
11
Discussion
Fig. 7 The surgical flap has been raised and the tooth
portion of the prosthesis has been positioned. The
amount of bone needed to graft the area can be
visualized.
Fig. 8 Harvested bone from the iliac crest has been
positioned in the anterior region in the volume needed
as determined by the diagnostic prosthesis.
Fig. 9 Panoramic views of the bone graft in position
(upper view) and the implants in position before
uncovery of the implants at second stage (lower view).
procedure to augment both right and left
sinuses and at the same time place bone
anteriorly to build up the labial surface of
the ridge. The diagnostic prosthesis was
used to determine the amount and
position for augmentation (Fig 7). Bone
was harvested from the iliac crest and
additional bone was placed in the
anterior area to allow for a percentage of
shrinkage (Fig 8). During an uneventful
healing period the patient wore her old
denture with its flange removed to allow
for no pressure on grafted bone). Multiple
implants
(osseotite
3i
Implant
Innovations, Palm beach Gardens, FL)
were then placed in the maxilla (Fig 9).
These implants healed for a period of six
months after which they were restored
with a flangeless fixed restoration (Fig 10
and 11).
12
An edentulous patient who considers
replacement of a removable prosthesis
must understand that the original
prosthesis is made up of several
components that relate to the overall
effect of the prosthesis. The flange
provides lip support and esthetics. The
teeth provide esthetics, lip support,
phonetic assistance and masticatory
function. The palate provides vertical
support for the prosthesis, aids in
retention, and has a significant effect on
the phonetic experience of the patient. All
the mentioned components, together with
lingual extensions, are involved in overall
retention. Replacement of the prosthesis
with a fixed reconstruction does away
with the flanges and the palatal portion.
The immediate effects are a change in
phonetics related to the loss of the palatal
and lingual portions of a prosthesis, and a
change in the facial esthetic profile due to
the loss of the flange. These changes may
be desirable but in many situations, these
changes come as a surprise to the patient.
Not letting a patient know of the possible
consequences of replacing a removable
prosthesis with a fixed prosthesis is
unacceptable and may lead to untoward
consequences for the restoring dentist and
the dental technologist.
Certain prosthodontic procedures
include diagnosis and management of
upper lip support. It is important to
establish which aspect of the lip needs
support. The lower aspect of the lip is
supported by the dentition. The upper
aspect is supported by the nasal spine and
basal bone. The upper lip may also appear
to be deficient due to thin soft tissue of the
upper lip. The diagnosis and treatment
should be based upon clinical,
photographic, lateral cephalogram and the
patient’s own perspective on esthetics.
This can be further evaluated by using wax
rims placed under the lip, or even using a
moistened cotton roll positioned under
the lip. It is important to also decide
whether the underlying lack of lip support
is due to a retrognathic maxilla.
This paper describes a unique method to
evaluate lip support. Use of a split
prosthesis to evaluate upper lip support
allows one to judge where a lack of support
is present. Using the flange portion of the
prosthesis one can evaluate the upper
portion of the lip for support. Using the
tooth section of the prosthesis one can
evaluate the lower portion of the lip. Once
the decision is made as to where to
deficiency lies, appropriate treatment can
be planned for and provided. This paper
Fig. 10a View of the patients smile once restored as
well as the patients profile showing esthetic results.
Fig. 10b View of the patients smile once restored as
well as the patients profile showing esthetic results.
Fig. 11 Occlusal view of the final reconstruction. The
restoration was made in three sections and restored
full function and esthetics for this patient.
presented the use of autogenous bone to
support the contours of a deficient lip.
Other methods are available to
increase support to the upper lip. Soft
tissue replenishment of the upper lip can
be established by injection of collagen
into the upper lip. These treatments are
of a temporary nature only and have
little place in permanent management of
a weak upper lip. Newer materials have
been developed that combine collagen
with polymethylmethacrylate acrylic
(Artecoll, Canderm Pharma Inc., StLaurent, QC) to create “permanent
materials” but little data is available on
the dental application as has been
described in this paper. It appears that
this material can be used in soft tissue
but definitive recommendations have
not been made as to its use in a
Spectrum May/June 2003
subperiosteal approach for lip support. Bone grafting with
autogenous bone gives a very predictable result when the teeth
are in an esthetic anterior-posterior relationship, and when
there is a lack of upper lip support. Synthetic bone products
alone or in combination with autogenous bone can yield good
results. This grafting can be accomplished utilizing a tunneling
technique when sufficient soft tissues are present or with an
inflatable bladder that will expand tissues and create a neat
pocket. Non-resorbable crystals such as hydroxyapatite can
yield good results but are difficult to reverse and may preclude
implant placement in the future. Orthognathic movement of
the maxilla forward is the indicated treatment when the
dentition and bone are both retrognathic and require anterior
placement. When the upper portion of the upper lip is treated,
care should be taken to evaluate the nasolabial angle to insure
that it does not become too acute. Likewise all of these
treatments will cause some up turning of the nasal tip. Severely
acute and obtuse nasolabial angles should be avoided.
Prosthodontic methods are also available that use a removable
approach to bulk out the lip by placing a removable acrylic gingival
prosthesis under the lip to support the lip. Other materials (silicone
based materials) have also been used to create a flexible prosthesis with
the same effect. Using one of these methods can avoid surgery if
surgery is not desired or is unsuccessful.
Conclusion
A unique approach was undertaken to evaluate the soft tissue
support needed by a patient requesting an implant based restoration.
The prosthesis is easily fabricated and accurate in the information
that it provides as a diagnostic prosthesis.
14
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