Rajiv Gandhi University of Health Sciences, Bangalore s12

RAJIV GANDHI UNIVERSITY OF HEALTH SCIENCES

BANGALORE, KARNATAKA.

ANNEXURE – II

PROFORMA FOR REGISTRATION

TOPIC OF DISSERTATION

1. Name of the candidate and Address (in block letters)

/ Dr. ABHINAV MOHAN.K
DEPT OF PROSTHODONTICS
VYDEHI INSTITUTE OF DENTAL SCIENCES & RESEARCH CENTRE,
# 82, EPIP AREA, NALLURAHALLI, WHITEFIELD,
BANGALORE- 560066

2. Name of the Institution

/ VYDEHI INSTITUTE OF DENTAL SCIENCES AND RESEARCH CENTRE, BANGALORE

3. Course of Study & Subject

/
M.D.S, PROSTHODONTICS

Date of Admission to the course

/
24th JULY 2013

Title of the topic

/ “COMPARATIVE EVALUATION OF MICROLEAKAGE IN THREE CORE MATERIALS WITH CONVENTIONAL AND UNCONVENTIONAL PLACEMENT OF CROWN MARGINS - AN INVITRO STUDY”
6. / BRIEF RESUME OF THE INTENDED WORK:
6.1. Need For The Study :
Grossly mutilated vital teeth requiring large class II restorations extending up to the cemento-enamel junction is a common clinical condition in dentistry. These restored teeth invariably will require a full crown to protect the remaining tooth structure. The conventional procedure for crown preparation has been to place the gingival margins on the tooth structure. However, this requires a radical preparation of the remaining structure resulting into loss of retention and resistance form. By placing the margin on the core material, preservation of the remaining structure and enhancement of retention and resistance form may be achieved. It is however understood from literature that the conventional perfect margins on the tooth structure will definitely show good prognosis, but many a times it becomes difficult to achieve perfection and therefore this study has been undertaken to assess the effect of placing the margins on the core on the prognosis with microleakage as a main factor. This study is undertaken to evaluate and compare the microleakage of three commonly used core materials.
6.2 . REVIEW OF LITERATURE:
Ø A study 1 was conducted to evaluate the microleakage with the various new methods available. It was concluded that of the different types of tests available to assess microleakage, the dye penetration test was the simplest and commonly used method.
Ø A study2 was done to determine the physical properties of the following six different core build up materials (1) Tph spectrum (2) Ti-core (3) Vitremer (4) Dyract (5) Chevron Silver and (6) Duralloy. The properties like diametric tensile strength, compressive strength and flexural strength were compared. They concluded that all the materials met with the minimum specifications required to be used as a core build up material except for amalgam.
Ø A study3 was conducted to verify the influence of the core materials in the microleakage of cast crowns. This research studied three experimental conditions: (a) teeth with prefabricated post and partial composite resin cores, (b) teeth with cast metal posts and core, and (c) teeth with prefabricated posts and composite resin cores. They concluded that there was no statistical difference in microleakage at cervical region of axial wall between (a) and (c). However (b) showed higher microleakage, which reached medium third of axial wall.
Ø A study4 was conducted to evaluate the microleakage of six recent restorative materials and it was concluded that the sealing ability of materials play a major role in preventing microleakage. From the study, the sealing ability in terms of microleakage was summarized in increasing order as: Self-cured GIC (Ketac Molar Easy Mix), Compomer (Dyract), Packable composite (Filtek P60), Resin modified Glass ionomer cement (GC Fuji II LC), Micro filled composite (Durafill VS), Nanocomposite (FiltekZ350).
Ø A study5 was done to evaluate marginal leakage under complete metal crowns using three adhesive cements: two resin cements (one self cure, one dual cure) and glass ionomer cement. They concluded that between three groups, metal crowns cemented with multilink cement showed significantly less microleakage at both the interfaces.
Ø A study6 was conducted to evaluate the microleakage under crowns cemented with conventional glass ionomer cement, resin – modified glass ionomer cement and adhesive resin cement and they concluded that microleakage of the three cements used for the study was comparable. The resin-modified glass ionomer cement exhibited more microleakage than adhesive resin cement but less than glass ionomer, though the difference was insignificant amongst all the test groups.
Ø A study7 was conducted to compare the microleakage of three recent resin based core materials (paracore, multicore, fluorocore).The microleakage of these materials were assessed at the occlusion and at the cervical regions with the dye penetration method and they concluded that the microleakage at occlusion of paracore was less than multi core which was lesser than fluorocore. At cervical region microleakage of paracore was less than Multicore and fluorocore showed the highest leakage.
6.3.OBJECTIVE OF THE STUDY:
Aim of the present study is to:-
o Evaluate microleakage under the crowns fabricated on MULTICORE core material with conventional and unconventional margin placement.
o Evaluate microleakage under the crowns fabricated on KETAC SILVER core material with conventional and unconventional margin placement.
o Evaluate microleakage under the crowns fabricated on FUJI IX core material with conventional and unconventional margin placement.
o Compare the microleakage among the above mentioned situations.
7. / MATERIALS AND METHODS:
7.1 SOURCE OF DATA:
7.1.1. Type of study: Invitro comparative analytical study.
7.1.2. Study models: Intact 60 extracted human premolars.
7.1.3 Materials:
· Three core materials used in this study are:
1. MULTI CORE™ [dual cure flowable composite , IVOCLAR]
2. KETAC SILVER™ [cermet , 3M ESPE]
3. FUJI IX™ GP [GIC, GC].
· Porcelain fused to metal crowns:
1. Ceramic-VITA™
2. Metal Coping-CERABOND™ (Ni-Cr)
7.2 METHODS OF COLLECTION OF DATA
Sample size:
Ø A total sample size of 60 intact premolars will be collected for this study.
Ø They will be divided into 3 major groups of 20 each for the three different core materials used.
Ø Group A→ 20 premolars restored with MULTICORE material.
§ Sub Group A1- Ten premolars with conventional crown preparation; denoted as A10 to A19
§ Sub Group A2- Ten premolars with crown margins placed on the core material; denoted as A20 to A29
Ø Group B →20 premolars restored with KETAC SILVER material;
§ Sub Group B1- Ten premolars with conventional crown preparation; denoted as B10 to B19.
§ Sub Group B2- Ten premolars with crown margins placed on the core material; denoted as B20 to B29.
Ø Group C→ 20 premolars restored with FUJI IX GP material.
§ Sub Group C1- Ten premolars with conventional crown preparation; denoted as C10 to C19.
§ Sub Group C2- Ten premolars with crown margins placed on the core material; denoted as C20 to C29.
Sampling Procedure:
Ø Sixty intact extracted pre molars will be collected, scaled and stored in 2% hydrogen peroxide.
Ø A large class II cavity will be prepared extending up to the cemento- enamel junction.
Ø The prepared cavity will be restored with three different core materials.
Ø Tooth preparation using the standard protocol, will be done on all the 60 premolars to receive porcelain fused to metal crown.
Ø Out of the 60 premolars, 30 will be prepared with the conventional margin and the other 30 will be prepared with margin on the core material.
Ø The specimens will be molded with addition silicone impression material (3M ESPE™ putty and light body) to obtain a gypsum model (die stone type IV-KALROCK™) on which the wax patterns (BEGO™) of the copings will be made4.
Ø Porcelain fused to metal crowns will be fabricated and cemented over the teeth with resin cement (RelyX™ 3M ESPE) and checked for marginal fit under the stereomicroscope.
Ø For the samples which do not meet the required standards, crowns will be refabricated.
Ø The crowned samples will then be subjected to mechanical cycling with a load of 400N at the rate of 5 cycles/second up to 36,000 cycles to provide artificial aging of the samples 6 and later followed by thermo cycling6, maintaining 700 cycles between 5°c to 55° C. The immersion time of each specimen will be 30 seconds with a transition time of 15 seconds.
Ø After thermo cycling, the specimens will be immersed in 0.5% aqueous solution of basic fuchsin for 8 hours, for three days1. Then, each tooth will be washed in water and longitudinally sectioned in mesio-distal direction using a diamond disc to evaluate the extent of dye penetration.
Ø Microleakage will be assessed with the dye penetration method.
Ø The sectioned samples will be evaluated under the stereomicroscope (MAGNUS MSZ-TR OLYMPUS™ 40 x magnification) to assess the extent of dye penetration.
Ø The extent of dye penetration will be scored on an ordinal scale with the following values.
SCORE / EXTENT OF DYE PENETRATION
0 / No dye penetration
1 / Dye penetration up to one third of axial wall
2 / Dye penetration up to middle third of axial wall
3 / Dye penetration up to full length of axial wall
Data Collection methodology:
1. Qualitative Analysis of microleakage will be done using stereo microscope (MAGNUS MSZ-TR OLYMPUS™40x magnification) ; Dept of Prosthodontics-VIDS&RC, Bangalore.
2. Photographs of the samples will be taken using a digital camera (Sony cyber shot™ steady shot DSC W320) in Dept of Prosthodontics- VIDS & RC Bangalore.
3. Mechanical loading will be done using the universal testing machine NANO (Bangalore Integrated systems solutions, Peenya, Bangalore).
4. Customized manual thermo cycling procedure, as per the ISO TR standard 11405:1994, will be done to create artificial aging on the samples (Dept.of Prosthodontics - VIDS & RC)
Statistical Analysis:
Values will be statistically analyzed by
· Kruskal Wallis Test.
· Mann Whitney U Test.
7.4 Does the Study require any investigation or intervention to be conducted on patients or other human subject or animals? If so, please describe briefly.
Yes, require sixty intact extracted human premolars.
7.5 Has Ethical Clearance been obtained from your Institution?
Yes
8. / LIST OF REFERENCES:
1. Gonzalez NAG, Kasim NHA, Aziz RD. Microleakage testing. Annals Dent Univ Malaya 1997;4:31-37.
2. Saygılı G, Sahmali SM. Comparative study of the physical properties of core materials. The International Journal of Periodontics & Restorative Dentistry 2002;22(4).
3. Campos TN, Arita CK, Missaka R, Adachi LK, Adachi EM. Influence of core materials in the microleakage of cast crowns.Cienc Odontol Bras 2005;8(4):13-17.
4. Gupta V K, Verma P and Trivedi A. Evaluation of microleakage of various restorative materials: An in vitro study. J Life Sci 2011;3(1):29-33.
5. Bhandari S, Aras M, Chitre V. An in vitro evaluation of the microleakage under complete metal crowns using three adhesive luting cements. J Indian Prosthodont Soc 2012 Apr-June;12(2):65–71.
6. Shah R, Shah D. An evaluation of microleakage under crowns cemented with different luting agents. Journal of Advanced Oral Research 2012 Sep – Dec;3(3).
7. Rajkumar B, Iqbal M, Chandra B L, Singh R, Gupta V, Gupta A. Comparative evaluation of microleakage of three recent resin based core materials: An in vitro study. Biomedical Journals of India 2012 Dec;24(2).