SYNOPSIS PRESENTATION
Surface characterization of human teeth post radiation and
material testing for radiation attenuating properties in
shielding of healthy tissues during head and neck cancer
therapy
Jagadish K
Reg. No: 183/July 2015
Junior Research Fellow
Yenepoya University
Guide:
Dr. Riaz Abdulla
Professor
Department of Oral Pathology
Yenepoya Dental College
Yenepoya University
Co-guide:
Dr. Rekha P.D.
Deputy Director & Professor
Yenepoya Research Center
Yenepoya University
1
CONTENTS
Sl. No
Index
Page no.
1
Introduction
3-8
2
Aims and objectives
9
3
Literature review
10-23
4
Lacunae in the literature
24
5
Social relevance
25
6
Materials and methods
25-40
7
Statistical analysis
41
8
Study plan
42
9
Budget
43
10
Time line
44
11
References
45-48
12
Annexures
49-51
2
Introduction
• Head and neck cancer (HNC) is among 10 most common
cancers globally.
• Accounts for one fourth of male cancers and one tenth of
female cancers. (C.J.K. Francis, 2016)
• Accounts for approximately 30 per cent of all cancers in
India. (Mehrotra R et. al, 2005).
• International scenario: 550,000 cases with around
300,000 deaths each year (Jemal A. et. al, 2011) .
• Sixth leading cancer by incidence worldwide. (Jemal A. et.
al, 2007).
• A recent survey of cancer mortality in India shows cancer
of the oral cavity as the leading cause of mortality in men
and responsible for 22.9% of cancer-related deaths
(Dikshit R et. al, 2012).
3
Figure A: 1. Carcinoma - buccal mucosa, 2. Carcinoma – tongue, 3. Carcinoma –
palate, 4. Carcinoma- lip, 5. Carcinoma – alveolar ridge
Source: Yenepoya Dental College.
4
Introduction
Treatment:
• Surgery
• Chemotherapy
• Radiotherapy
The radiation dose needed for cancer treatment is based on the
location and type of malignant disease, and whether or not
radiotherapy will be used on its own or in combination with
other treatment options.
Most patients with head and neck carcinomas, treated with a
curative intent, receive a dose of 2 Gy per fraction delivered
five times per week, up to a total dose of 64–70 Gy.
5
Side effects of Radiotherapy
•
•
•
•
•
Acute complications
Oral mucositis
Infection: fungal, bacterial
Salivary gland dysfunction: sialadenitis, xerostomia
Taste dysfunction
•
•
•
•
•
•
Chronic complications
Mucosal fibrosis and atrophy
Salivary gland dysfunction: xerostomia, dental caries
Soft-tissue necrosis
Osteoradionecrosis
Muscular fibrosis, cutaneous fibrosis, or trismus
Figure B: 1. Candidiasis, 2. Mucositis, 3. Denture stomatitis, 4.
Osteoradionecrosis, 5. Radiation caries, 6. Severe attrition
(Source: Yenepoya Dental College )
7
Introduction
Figure C: Radiation zone
8
Aim and objectives
Aim of the study:
To evaluate the impact of ionising radiation on teeth structure
and composition and to study radiation attenuating
properties of various material composites.
Objectives of this study:
• In vitro characterization of tooth structure, morphology and
composition using radiation as an intervention factor.
• Quality of life (QOL) in patients undergoing radiotherapy for
head and neck cancers.
• Radiation dosimetric studies to evaluate shielding properties
of various material composites.
9
Review of literature
International scenario:
Evaluation of radiation impact on dentition:
– Radiotherapy can affect normal tissues and tooth
microstructure and existing protective measures is not
enough to prevent the damage. Radiation induced
caries is a type of tooth degeneration that is
irreversible (Alimani-Jakupi et. al, 2012).
– Changes in quantity and quality of saliva, difficulty in
swallowing and performing oral hygiene and changes
in oral microbiota can be categorised as indirect
effects.
– Effects on dental structure including changes in
crystalline
structure,
enamel
and
dentin
microhardness, dentino-enamel junction, and acid
solubility of enamel can be categorised as direct
effects (Silva AR et. al, 2009).
10
Review of literature
• Radiotherapy induces alterations in the healthy
oral tissues. Studies were performed where the
subjects were treated with a radiation dosage of
50- 70 Gy over a period of 5–7 weeks. In vitro
studies showed Salivary gland impairment in rats
subjected to dosage rate between 2 and 60 Gy
(Bartel-Friedrich S et. al, 2000). Morphological
and structural changes of enamel and dentin of
rats were observed in 30-70 Gy radiation
treatment under Scanning Electron Microscopy
(Zhang X et. al, 2004).
11
Review of literature
• Direct effects of radiation on the development
of dental caries is assessed by irradiating the
human teeth of different types namely human
deciduous teeth and human permanent teeth
and assessing the radiation induced changes
in mechanical properties of the teeth through
different
tests
for
mechanical
and
morphological property, crystalline structure
and chemical analysis (de Siqueira Mellara T
et. al, 2014)
12
Review of literature
• Methods to evaluate effects of gamma
radiation:
Scanning Electronic Microscopy (SEM) studies
and Nano-scratch tests.
Micro-hardness tests.
Fourier Transform Infrared (FTIR)
Spectroscopy.
X Ray Diffraction analysis.
13
Review of literature
Different micro-structural properties, Progressive
micro morphological alterations of enamel and
dentin structures are studied.
Inter prismatic portions of enamel surface give a fair
idea of radiation-induced side effects and dentin
fissures, collagen fibres and dentinal tubule
obliteration is observed in the inner region of the
tooth at the dentin region (J, Huang Y et. al, 2014.)
14
Review of literature
Measurement of Smooth micohardness of teeth by Vickers microhardness
test is one of the widely followed procedures to analyse surface
profilometer parameters.
SMH values are calculated through Vickers microhardness test using
validated hardness indices.
Smooth microhardness of the enamel surface had a proportional increase
with the radiation dose.
Higher radiation dose at the range of above 60Gy minimized smooth
microhardness (SMH) values. (Rodrigues LK et.al, 2014).
Nano scratch tests and Scanning Electron Microscopic (SEM) studies were also
performed to evaluate the friction behaviour of enamel slabs before and
after treatment with identical radiation procedures.
In the analysis of the interacting factors, microhardness at different depths
and different irradiation doses, it was observed that enamel
microhardness values decreased in superficial depth up to 30 Gy
cumulative dose but increased with doses higher than that. In the middle
enamel, microhardness did not differ significantly compared with the nonirradiated enamel after cumulative radiation doses of 10, 30, 40, 50 and
60 Gy. (Qing P et. al, 2015).
15
Review of literature
Irradiation induced a reduction in enamel crystallinity and
enlarged crystals from XRD analysis. The crystallinity of
enamel has been widely reported to play an extremely
important role in its mechanical properties.
Given that, the reduction in crystallinity indicated decreased
mechanical properties, such as a reduction in hardness.
Sound enamel with a high crystallinity shows excellent
mechanical and anti-wear properties. Both perpendicularsectioned and parallel-sectioned enamel segments get their
crystallinity degraded after irradiation, which may account for
the inferior nano-scratch resistance.
Enlarged crystals have been observed in the enamel after
irradiation, which might contribute to the reduction of nanoscratch resistance in enamel after irradiation. (Huang S et.al,
2010).
16
Review of literature
Questionnaire study:
Quality of life assessment studies were carried out on patients in longterm survivors of advanced oral and oropharyngeal cancer treated
with preoperative chemo radiotherapy followed by surgery
(combined treatment = multimodal therapy).
All patients had T2–T4 tumours and all received loco-regional radical
resection and simultaneous microvascular reconstruction. From
1990 to 1998, 181 patients have been treated at the University
Hospital of Cranio-Maxillofacial and Oral Surgery in Vienna.
100 (55%) of these patients were alive and free of disease in 2000.
Sixty-seven of them completed the EORTC questionnaires QLQ 30
and QLQ H&N 35.
Questionnaires found to be very good tools for determining QOL,
which constitutes part of the therapeutic success.. It was found that
combined treatment not only offers the best chances for survival,
but also allows a subsequent QOL, that is comparable to other
forms of therapy (Klug C et. al, 2002)
17
Review of literature
Development of radiation shielding devices:
Raising need to find efficient shielding materials that
can not only offer protection from ionizing radiation
but also are least harmful themselves in aspects of
their exposure (Erdem M et. al, 2010).
Significant research efforts have been focused toward
designing efficient, lightweight, cost-effective, and
flexible shielding materials for protection against
radiation encountered in various industries (Harrison
C et. al, 2010).
18
Review of literature
Development of radiation shielding devices:
Polymer composites have become attractive candidates for
developing materials that can be designed to effectively
attenuate photon or particle radiation
Polymer reinforced with Micro/Nano-whiskers/fibres/tubes, Micro
or nano particles/powder, clay platelets are studied and their
attenuation coefficients are evaluated.
The results indicated that equal shielding effectiveness was
achieved by 8 mm thick pristine graphite epoxy material, 1.8
mm of Br2 intercalated graphite epoxy material and less than
1.4 mm thick IBr intercalated graphite epoxy.
Thus, intercalated IBr composite significantly reduced the mass of
the shield.
It concluded that composites with a few heavy atoms within the
light matrix acts as a more efficient shield against high energy
photons than a uniform, electron-rich material (Harrison C et.
al, 2008 and Ajayan PM et. al, 2006.)
19
Review of literature
Development of radiation shielding devices:
The composite materials were also tested for high-energy
electron (100 keV to 1.16 MeV) absorption as a function
of areal densities of all composites. Interestingly, they
found that regardless of the material been used, the
absorption was independent of atomic number of the
material and limited by areal density.
Moreover,
intercalation
increased
the
shielding
effectiveness because of their higher mass density.
Similar outcomes were achieved with other formulated
intercalations with polymer substances with heavy metal
intercalations. Therefore, this is a novel alternative
towards reduction or replacement of heavy metal based
radiation shields. (Zhong WH et.al, 2009).
20
Review of literature
• Barium sulphate based sheets and shielding apparatus have a
significant role to play in this regard. Barium sulphate is not harmful
to body and its performance as radiation shield has been evaluated.
Shielding rate was found to be effective with increase in particle
packing and porosity.
• This study evaluated shielding ability of barium sulphate at 30 kVp,
60 kVp, 100 kVp and 150 kVp and compared the results with lead
equivalent test method of X-ray protective supplies in the Korea
Industrial standard.
• According to the results, the manufactures sheet showed similar
shielding ability to that of 0.5 mm lead equivalent, and its barium
sulphate packing was found to be satisfactory considering its
flexibility. Therefore, a radiation shielding sheet made from barium
sulphate and liquid silicone resin mixtures, which are environmentfriendly shielding materials, instead of lead, by using this process
will have excellent shielding ability in examinations in radiology and
nuclear medicine departments. (Park C et. al, 2001 and Salah N et.
al, 2001).
21
Review of literature
Investigation of radiation shielding properties of
BaSO4/Polyvinyl Alcohol (PVA) composites is being done.
Moreover, the variation of these properties with the BaSO4
concentration in PVA on the basis of measurement of the
linear attenuation coefficient and X-ray protection are also
studied. The photon attenuation coefficients have been
investigated. The linear attenuation coefficients have been
measured using a gamma spectrometer with NaI (Tl)
detector and MCA at 59.54 keV. The X-ray attenuation test
was performed using the diagnostic X-ray machine for
energy of 45 kVp. Attenuation ability of BaSO4/PVA
composites in the X-ray energies is been confirmed.
Effectiveness in radiation ability increases with increasing of
the thickness and the concentration of BaSO4 (M.A. EISarraf et. al, 2013 and Thongpool V et. al, 2015.)
22
Review of literature
Composite circular disc containing different ratios
of acrylic and barium sulfate (BaSO4) were made
in-house to evaluate the percentage attenuation
from these composite shields in 60Co gamma
rays. A maximum of 8% radiation attenuation was
achieved using 1:4 ratio of acrylic-BaSO4
composite shields. The study proposes BaSO4 as
one of the compounds in combination with
acrylic resin or any other thermoplastic
substances for making biocompatible radiation
attenuating devices (Abdulla R et. al, 2015)
23
Lacunae in the literature
• Lack of evidence on direct effects of radiation
resulting in dental caries
• Characterization of teeth surface microstructure
and composition under the effect of medical
ionising radiation.
• Lack of demographic evidence on patients
perspectives towards quality of life and side
effects caused by radiotherapy.
• Development of biocompatible, intra/extra-oral
radiation shielding devices in radiotherapy for
head and neck cancers.
24
Social relevance
• Head and neck cancer being the most dreading
category in middle class people around the globe,
especially in India, this study will be a
contribution into investigating radiotherapy
effects and ways in which the treatment need to
be modified to generate maximum benefit with
minimum risk involved.
• Development of radiation shields to prevent
healthy tissues and glands from ionising radiation
will act as complement approach that could be
integrated into radiotherapy regime.
25
Methodology
•
Patients, sample collection and ethical issues:
Study will be conducted after the approval from the Yenepoya
University Ethics committee.
•
Selection criteria:
Study

Effect of radiation on structure and composition
of dentition
Selection criteria
Inclusion: Healthy teeth (Ca/P ratio-1.8-2.0)
Exclusion: Carious and deformed teeth, samples
with Ca/P ratio falling outside (1.8-2.0) range

Dosimetric analysis on material composites.
Inclusion: Elemental compounds with high
Z(Atomic mass) values, Relatively less toxic with
biocompatible properties
Exclusion: Elemental compounds with toxic
properties, heavy metal compounds.

Questionnaire study to analyse side effects of
radiotherapy on head and neck cancer patients.
Inclusion: Patients diagnosed with head and neck
cancers, patients post radiotherapy sessions (3
months, 6 months, 1 year)
Exclusion: Patients diagnosed with head and neck
cancers but without radiotherapy being prescribed. 26
Methodology
Sample size:
Study

Effect of radiation on structure
Sample size (n)
54 (Based on effect size = 4)
and composition of teeth

Dosimetric analysis on material 30 (Based on convenient sampling)
composites.

Questionnaire study to analyse
50 (Based on convenient sampling)
side effects of radiotherapy on
head and neck cancer patients.
27
Methodology
Objective -1
Sample collection
Sectioning and
preservation
Radiation exposure
Surface characterization
and composition analysis
Methodology
1. Sample collection:
– Human permanent teeth samples
– Department of Oral surgery, Yenepoya Dental
college
2. Sectioning:
– Bucco-lingual sectioning- using diamond disc.
– Preservation in 1x PBS
3. Radiation exposure:
– Medical X ray Linear accelerator generated.
29
Methodology
Radiation dosage:
• Control samples: no radiation exposure
• Positive control: Surface etching using 30%
Phosphoric acid
• Experimental samples: 4 doses of radiation
starting from 20, 40, 60, 80 grays exposed to the
buccal surface.
30
Methodology
Surface analysis

Conformal and chemical
analysis

Raman spectroscopy

Scanning Electron Microscope
studies
Surface micro hardness

FTIR (Fourier transform
infrared spectroscopy)

Surface profilometry


XRD (X Ray Diffraction)
Micro Computed Tomography,
2D and 3D slice projections and
variations of teeth using
Synchrotron based Micro CT
(RRCAT- Raja Ramana Centre
for Advanced Technology)
RADIATION EXPOSURE
31
Methodology
• Field Emission Scanning Electron Microscope analysis
(FESEM):
– Ultra structure and micro structural properties of surface of teeth
exposed to different grades of treatment radiation doses.
– The extra high tension (EHT) voltage level and magnification will
be prescribed as suitable to analyze the micro/ultra structure (de
Siqueira Mellara T et.al, 2014).
• EDS (Electron Density Spectroscopy):
– The regions of interest will be further amplified and the
composition and distribution of elements will be analyzed by EDS
(Oxford Instruments, England). Settings included for
measurements viz. Direct electron transfer (DET) area, window,
signal A, In-Lens; resolution and working distance, will be fixed as
appropriate (Eimar H et. al, 2011).
32
Methodology
• Microhardness test: Microhardness tests will be carried
out particularly using 2 standard indenters viz. Vickers
and Knoop.
• The concept behind the Knoop microhadness indenter
is to measure the longer diagonal within the
impression area produced by an elongated pyramidal
diamond.
• The concept behind the Vickers microhadness indenter
is to calculate the average value of the two diagonals
within an impression area produced by a pyramidal
diamond
• Both tests will be carried out with appropriate loading
time, loading force and Hardness values will be
calculated using respective principles (Tabor D, 2000).
33
Methodology
• Surface profilometric analysis: A profilometer is a
device used to measure the roughness of a surface.
Gives difference between the high and low point of a
surface in nanometres. Stylus profilometry would
involve traversing the surface with a diamond-tipped
stylus. The tip of standard radius (1.5-2.5μm approx.)
will be selected. (Field JC, 2012).
34
Methodology
• Fourier Transform Infra-Red Spectroscopy (FTIR)
analysis:
– Samples will be analysed using Attenuated total reflectionFourier transform infrared spectroscopy (ATR-FTIR). The
samples will be placed directly in the instrument
(Shimadzu IR Prestige 21) and compositions will be
determined by ATR-FTIR spectra at appropriate mid
frequency range and resolution (Krafft et. al, 2009, GulleyStahl et al., 2009).
35
Methodology
• X ray diffraction (XRD) analysis: Phase composition of
representative teeth samples before and after radiation
treatment will be measured using X-ray powder diffraction
(XRD). Cu-Kα radiation (λ=1.5406 Å) working at appropriate
energy and voltage values. The diffraction patterns will be
recorded in an appropriate scan speed. The diffraction
patterns will be registered within appropriate angle range
values. The temperature was set using Na (Ti) I Scintillation
counter with Be as window material and appropriate window
diameter. Phase identification will calculated from the
resulting diffractograms (Uvarov et al., 2011).
36
Methodology
• Micro Computed Tomography (Micro CT) analysis:
MCT is a high resolution, non-destructive 3D imaging
technique to investigate internal structures of
objects.
• This experiment will be carried out at Imaging Beam
line (BL-4) at Indus Indus-2 synchrotron radiation
source operating at appropriate energy and current
source. The absorption radiographs of the samples
were obtained at a distance of 5 mm.
• All acquired images will be analyzed using Image J
software. (Fatima A et.al, 2016)
37
Methodology
Objective -2
Questionnaire study to evaluate Quality of life (QOL) in patients undergoing radiotherapy
for head and neck cancers;
Ethical clearance
Patient recruitment
and consent
Administering
questionnaire
Follow up at 3 month, 6 month and
12 month interval
Results and statistical
analysis
Methodology
Objective- 3
Radiation dosimetric studies to evaluate shielding properties of various material
composites:
Literature search and selection of
appropriate material composite
with radiation shielding shielding
and biocompatible properties
Preparation composite discs of
appropriate thickness
Radiation exposure and dosimetric
analysis
Results and Statistical analysis
39
Methodology
Statistical analysis
• Data will be expressed as mean ± standard deviation.
• Student’s t-test will be used for comparing different
groups.
• 2 way ANOVA is study variance between groups.
• p<0.05 will be considered as statistically significant.
• Data will be analyzed using SPSS software (version 22).
40
Study plan
Surface analysis
Conformal and chemical analysis


Scanning Electron Microscope studies
Surface micro hardness


Raman spectroscopy
FTIR (Fourier transform infrared spectroscopy)

Surface profilometry


XRD (X Ray Diffraction)
Micro Computed Tomography,
RADIATION EXPOSURE
QOL assessment; Questionnaire study
Preparation of material composites
Dosimetric analysis
Development of radiation shields
41
Time line
42
Budget requirements
Sl.
Description
No.
Budget (INR)
I year
II year
III year
Total
1
Scanning Electron Microscopy
20,000
30, 000
50,000
2
Surface profilometry
20,000
20,000
40,000
3
Micro hardness
15,000
15,000
30,000
4
X ray Diffraction
20,000
20,000
40,000
5
Fourrier Transform Infra Red Spectroscopy 10,000
10,000
20,000
6
Micro Computed Tomography (µ CT)
10,000
10,000
20,000
7
Medical radiation
5,000
10,000
15,000
8
Questionnaire study
10,000
10,000
20,000
40,000
9
Preparation of radiation shields
10,000
20,000
20,000
50,000
10
Dosimetric analysis
15,000
15,000
10,000
40,000
11
Publication
10,000
20,000
80,000
1,10,000
TOTAL
4,55,000
43
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Annexure 1.
Patient information sheet_synopsis_1.pdf
Annexure 2.
50
Annexure 3.
questionnaire_annexure_1.pdf
Thank You
52