Download bapuji dental college and hospital, davangere– 577 004.

RAJIV GANDHI UNIVERSITY OF HEALTH SCIENCES, BANGALORE,
KARNATAKA.
ANNEXURE – II
SYNOPSIS FOR REGISTRATION OF SUBJECTS FOR
DISSERTATION
1.
NAME OF THE CANDIDATE Dr. ARCHANA P BETUR
POST GRADUATE STUDENT,
AND ADDRESS
DEPARTMENT OF PEDODONTICS AND
PREVENTIVE DENTISTRY,
(IN BLOCK LETTERS)
BAPUJI DENTAL COLLEGE AND
HOSPITAL,
DAVANGERE-577004.
KARNATAKA
2.
NAME OF THE INSTITUTION
BAPUJI DENTAL COLLEGE AND
HOSPITAL, DAVANGERE– 577 004.
KARNATAKA.
3.
COURSE
OF
STUDY
AND MASTER OF DENTAL SURGERY (M.D.S) IN
PEDODONTICS & PREVENTIVE
SUBJECT
DENTISTRY.
4.
DATE
OF
ADMISSION
TO
30-05-2012
COURSE
5.
TITLE OF THE TOPIC
“COMPARATIVE EVALUATION OF
ANTIMICROBIAL AND PHYSICAL
PROPERTIES
OF
A
NEWER
DENTIN BONDING AGENT WITH
CETYL PYRIDINIUM CHLORIDE AN IN VITRO STUDY”
6.
BRIEF RESUME OF THE INTENDED WORK:
6.1: Need for the study:
"Mutans streptococci" are the most important bacteria associated with tooth
decay. S. mutans, the microbial species is the main pathogen responsible for the initiation
of caries and in the development of secondary caries.2
Bacterial microleakage has been claimed to be the main cause of pulpal
inflammation, necrosis and the eventual need for endodontic therapy after placement of
restoration, thus the biological sealing of the prepared dentin is considered critical for
successful restoration.2
The infiltration of the adhesive resins into demineralized dentin results in a
resin-dentin impregnation zone that not only provides strong bonding but also a hermetic
seal.2
The development of adhesive systems that have enabled variable cavity
designs to preserve intact tooth structure & treatment of caries has recently shifted from
the traditional method to that with downsized cavities. However when the attention is
focused on less removal of the tooth structure, it is possible that some active bacteria
reside in the cavity. 1
In spite of considerable improvement in recent years, polymerization
shrinkage and resultant contraction gaps in the tooth restoration interface continue to be a
significant problem associated with composite resin restorations. Poor adaptation to the
surrounding tooth substance may predispose to discoloration and bacterial colonization. It
is well known that bacteria that invade along the tooth restoration interface are the main
cause of secondary caries and damage to the pulp.1
There would be advantages if the materials applied after the cavity preparation
possessed antibacterial property, as this would overcome any problems caused by residual
bacteria in the cavity, and achieve a better prognosis.1
The antibacterial effects of non polymerized and immediately polymerized
adhesives are beneficial in the eradication of residual bacteria in the oral cavity. The
lasting antibacterial activity of polymerized adhesives may be effective in inactivating the
bacteria that invade the tooth-adhesive interface by invasion1
Hence there is a need of bonding agents with long lasting antimicrobial
property.
6.2: Review of Literature :
The adhesive systems are the components that come into contact and reacts with
the dentin substrate at the first stage of restoration. If the dentin bonding agents possess
antibacterial activity these bacteria can be eliminated, thereby preventing the secondary
caries.2 Thus the antibacterial activity of the adhesive systems applied to the dentin plays
an important role in the longevity of the restoration. 1
Thus incorporation of antibacterial agents into dentin bonding agents may be
helpful for the complete elimination of the residual bacteria in the cavity.1
An experimental primer containing 1% chlorhexidine was prepared and the
antibacterial activity was compared those with commercial adhesives. In both disc
diffusion tests and MIC/MBC measurements, none of the commercial products examined
found to have antibacterial effect comparable with the experimental primer. Therefore the
use of cavity disinfectant may still be necessary for eliminating possible harmful effects
caused by residual bacteria in the cavity.3
To provide resin based material an antibacterial activity, a new monomer,
methacryloxydodecylpyridinium bromide (MDPB) has been developed. The incorporation
of MDPB is considered to be a potential method of providing dentin adhesive systems
with antibacterial activity before and after curing and the antibacterial potential of a
bactericide immobilized within resin composite has been reported.3
Cetyl Pyridinium Chloride (CPC) is a well known and effective antibacterial agent, of
which its wide use as an Over The Counter drug and an oral hygiene aid is regulated by
Food and Drug Administration. Experimental resins containing 0%, 1% and 3% Cetyl
pyridinium chloride were polymerized and the bacteriostatic & bactericidal effects against
streptococcus mutans were determined. Cetyl pyridinium chloride released from the 0, 1
and 3% Cetyl pyridinium chloride resin sample into water was spectrometrically
quantified using a UV- vis recording spectrophotometer. The results demonstrated that the
bactericidal molecule still possessed significant contact bacteriostatic activity when it was
immobilized in resin matrix.4
The mechanism of antibacterial activity of Cetyl pyridinium chloride is ascribed to
the positive charge of the pyridinium group. This group attracts the negatively charged
cell membrane of bacteria, by which the cell membrane loses its electrical balance and
eventually the bacteria ‘explode’ under their own osmotic pressure, similar to bursting
soap bubble ( a process called bacteriolysis)4
A study was conducted on the antimicrobial activity of newer dentin bonding agents
on streptococcus mutans and Clearfil protect bond, Prime and Bond NT were found to be
most effective and Adper Easy One was least effective against Streptococcus Mutans 1
The antibacterial and adhesive property of chitosan was studied when added to the
newer dentin bonding agents and it stated that there exhibits an inhibitory effect on the
growth of Streptococcus Mutans compared to unmodified adhesive resin and it does not
adversely affect the adhesive properties 2
HYPOTHESIS:
Research hypothesis:

Incorporation of 1% and 3% Cetyl peridinium Chloride to Adper Easy One will
alter the antimicrobial property of the dentin bonding agent.

Incorporation of 1% and 3% Cetyl Peridinium Chloride to Adper Easy One will
not alter the microleakage & shear bond strength of the dentin bonding agent.
Null hypothesis:

Incorporation of 1% and 3% Cetyl Peridinium Chloride to Adper Easy One will
not alter the antimicrobial property of the dentin bonding agent.

Incorporation of 1% and 3% Cetyl Peridinium chloride to Adper Easy One will
alter the microleakage & shear bond strength of the dentin bonding agent.
6.3 Objectives of the study:
1. To evaluate and compare the antimicrobial property of Adper Easy One with 1% and
3% cetyl pyridinium chloride.
2. To evaluate and compare the microleakage of Adper Easy One with 1% and 3% cetyl
pyridinium chloride.
3. To evaluate and compare the shear bond strength of Adper Easy One with 1% and
3% cetyl pyridinium chloride.
MATERIALS AND METHODS :
SAMPLE SIZE DETERMINATION :
Sample size is determined by:
n = 2 t2 s2
d2
where, n = Required sample size for each group
t = A point on normal distribution with t = 2.13 at 95% confidence
s = Proved Standard deviation of different groups (from previous studies )
d = Minimum expected difference between the groups = 0.98
α = 5% level of significance(expectancy of type I error)
beta = 20% level of significance (expectancy of type II error)
1- beta = power of the study(80%)
n = 2 x (2.13)2 x (1.0)2
(0.98)2
n = 9.1 ~ 10
n(sample size per group) = 10

Minimum sample derived is 10 per group.
7.1 Source of data:
60 therapeutically extracted impacted third molar teeth will be collected and will be used
in this study.
Materials required:
- Microbial strains of streptococcus mutans
- Adper Easy One ( 3M ESPE )
- Cetyl pyridinium chloride ( HiMedia Laboratories Pvt Ltd )
- Spectrophotometer
- 1% methylene blue dye
- Binocular microscope
- Thermocycling unit
- Universal testing machine
7.2 Method of Collection of Data:
Study design: Experimental, in-vitro and between group study.
The study will be carried out in three parts:
1) To evaluate antimicrobial property
Data will be collected by recording the optical density, a measurement of turbidity that is
based on kinetics of bacterial growth, with the help of a spectrophotometer.
2) To evaluate microleakage
Microleakage will be measured by dye penetration test using a binocular microscope
3) To evaluate shear bond strength
Shear bond strength will be measured using universal testing machine.
The study groups which will be used in this study are :
GROUP A
Adper Easy One
GROUP B
Adper Easy One incorporated with
1% Cetyl Peridinum Chloride
GROUP C
Adper Easy One incorporated with
3% Cetyl Peridinium Chloride
Preparation of the sample :
Adper easy one with 1% cetyl peridinium chloride :
1% means 1gm in 100ml, thus for 5ml of Adper easy one, 50mg of cetyl
peridinium chloride will be added to make 1% concentration and mixed.
Adper easy one with 3% cetyl peridinium chloride :
3% means 3gm in 100ml, thus for 5ml of Adper easy one, 15omg of cetyl
peridinium chloride will be added to make 3% concentration and mixed.
1) To evaluate the antimicrobial property :
Test organism & Growth condition:
Clinical isolates of streptococcus mutans, naturally resistant to bacitracin will be
grown aerobically in Brain Heart Infusion broth.1
Direct contact test:
Direct contact test (DCT) is based on the turbidometric determination of bacterial
growth (i.e., by recoding the optical density, a measurement of turbidity that is based on
the kinetics of bacterial growth) with the help of a spectrophotometer.
30 samples, 10 in each group will be tested against the strain. The microtiter plates
will be held vertically and sidewalls of the wells will be coated with dentin bonding agent
and cured. Bacterial suspension is placed on it in a vertical position to ensure the direct
contact between the bacteria and the test material.1
Brain Heart infusion broth is added to each of the wells and gently mixed. The plates
are incubated and the optical density in each well is measured with the help of a
spectrophotometer.1
2)To evaluate microleakage:
30 therapeutically extracted impacted third molars will be randomly assigned to 3
groups. Class V cavities of standardized dimensions will be prepared on either buccal or
lingual surfaces, and respective groups of dentin bonding agents are applied and restored
with composite.
The teeth will be then thermocycled and nail varnish will be applied to the entire
tooth surface leaving a 2.0mm window around the restoration margin. The teeth will be
then immersed in 1% methylene blue dye solution for 24hrs at room temperature.
\
The teeth will be then sectioned through the center of the restoration. Each section
will be then examined under binocular microscope for dye penetration.5
3)To evaluate shear bond strength:
30 therapeutically extracted impacted third molars will be randomly assigned to 3
groups. Flat dentin surfaces will be created on each tooth and mounted.
Respective dentin bonding agent will be applied and light cured. Followed by
composite resin cylinder placement using a metallic disk, the specimens will be
thermocycled.
Then, the specimens will be stored in distilled water for 1 week. Each specimen
will be then loaded into Universal testing machine and the shear bond strength will be
measured until fracture occurs.7
STATISTICAL ANALYSIS:
All the results will be tabulated and subjected to appropriate statistical analysis :
 One way ANOVA will be used for multiple group comparison followed by
POST HOC Tukey’s test for group wise comparison.
7.3: Does the study require any investigation or interventions to be conducted on
patients or other humans or animals? If so, please describe briefly:
Yes, this study requires the collection of 60 impacted third molars extracted for
therapeutic reasons.
7.4 : Has ethical clearance been obtained from your institution in case of 7.3
Yes, recommendations of ethical committee are enclosed.
8.0 LIST OF REFERENCES:
1. Mithra N Hegde, Pavitra B Sampath, Priyadarshini Hegde. Assessment of
antibacterial properties of newer dentin bonding agents: an in vitro study.
Contemporary clinical dentistry 2011;2(3):165-169.
2. Shaymaa E Elaska. Antibaccterial activity and adhesive properties of a chitosan
containing dental adhesive. Quintessence International 2012;43:603-613.
3. Satoshi Imazato, Akiko Kuramoto, Tomoyuki Kaneko, Shigeyuki Ebisu, Roy R B
Russel. Comparison of antibacterial activity of simplified adhesive systems. Am J Dent
2002;15:356-360.
4. Naoko Namba, Yasuhiro Yoshida, Noriyuki Nagaoka, Seisuke Takashima, Kaori
Matsuura Yoshimoto, Hiroshi Maeda. Antibacterial effect of bactericide
immobilized in resin matrix. Dental materials 2009;25(4):424-430.
5. B M Owens, WW Johnson. Effect of new generation surface sealants on the
marginal permeability of class V resin composite restoration. Operative dentistry 2006;
31(4):481-488.
6. A M Gueders, JF Charpentier, AI Albert, SO Geerts. Microleakage after
thermocycling of 4 etch and rinse and 3 etch adhesives with and without a flowable
composite lining. Operative dentistry 2006;31(4):450-455.
7. N Ravikumar, P Shankar, R Indra. Shear bond strengths of two dentin bonding
agents with two desensitizers: an in vitro study. J Conserv Dent 2011;14(3):247-251.