RAJIV GANDHI UNIVERSITY OF HEALTH SCIENCES,
KARNATAKA, BANGALORE.
ANNEXURE – II

PROFORMA FOR REGISTRATION OF SUBJECTS FOR DISSERTATION

1. / NAME OF THE CANDIDATE AND ADDRESS
(IN BLOCK LETTERS) /

Dr. MOKSHADA M. BADADARE

POST GRADUATE STUDENT,
DEPARTMENT OF PROSTHODONTICS,
SRI HASANAMBA DENTAL COLLEGE & HOSPITAL, HASSAN -573201,
KARNATAKA.
2. / NAME OF THE INSTITUTION / SRI HASANAMBA DENTAL COLLEGE & HOSPITAL,
HASSAN -573201, KARNATAKA.
3. / COURSE OF STUDY AND SUBJECT /

MASTER OF DENTAL SURGERY IN PROSTHODONTICS CROWN AND BRIDGE

4. / DATE OF ADMISSION TO COURSE / 31 / 05 / 2011
5. /

TITLE OF THE TOPIC

/ “TO EVALUATE THE EFFECT OF TOOTH PREPARATION BURS ON THE RETENTION OF COMPLETE CAST CROWNS CEMENTED WITH THREE DIFFERENT LUTING CEMENTS:AN IN VITRO STUDY”
6.
M
7
8 /
BRIEF RESUME OF THE INTENDED WORK:
6.1 NEED FOR THE STUDY:
The complete cast crowns are one of the most important restorations in the armamentarium of restorative dentistry.1 However, dislodgement of cast restorations due to loss of retention is a frequently encountered problem in clinical practice.2
Retention is influenced by many factors like,1] Dislodging forces,
2] Stress concentration and
3] Surface area.
But, the primary factors affecting retention are design of the tooth preparation and cementing medium.2,3
Tooth preparation is done using different types of burs. Dental diamond burs are grinding instruments that are widely used because of their high efficiency of cutting and their versatility of shapes, dimensions, and grit sizes.4,5
The luting agents provide retention by mechanical interlocking of the cement into irregularities on the internal surface of the fabricated restoration and the tooth preparation.3,6,7
The prime objective of this study, is to evaluate the retention of complete cast crowns prepared with three different burs and cemented with three most commonly used cements.
6.2 REVIEW OF LITERATURE:
Worley JL et al in 1982 investigated the effects of cement on crown retention, and concluded that, a primary factor of crown retention is adhesion or mechanical interlocking of the cement to the crown. And there is significant improvement in retention of the restoration with the placement of shallow groove.8
El-Mowafy OM et al in 1996 investigated the effect of varying crown preparation taper and height on retention of metal ceramic crowns cemented with resin cements and concluded that teeth with short clinical crowns and short crown preparations shows reduced retention inspite of using proper type of luting cement.9
Ayad MF et al in 1997 conducted a study on effect of surface characteristics of teeth prepared for complete cast crowns and retention of respective cemented restorations and concluded that, significant differences were found among all three cements for finishing burs. Optimal retention of artificial crowns with zinc phosphate cement was recorded with tooth preparations completed with carbide burs.10
Tuntiprawon M in 1999 investigated the effect of axial surface roughness on the marginal seating and retention of silver-palladium crowns luted with zinc phosphate, glass ionomer, and resin cements and concluded that, the best retention for complete metal crown was demonstrated for tooth preparations ground with coarse diamonds and cemented with Panavia 21 cement. Differences in axial surface roughness had no effect on the marginal seating of the complete metal crowns.4
Yim NH et al in 2000 investigated the effect of dentin desensitizers and cementing agents on retention of full crowns using standardized crown preparations, and concluded that, the retentive strength of crowns cemented to dentin pretreated with desensitizer depends on the combination of cementing agents and dentin desensitizers.11
Ayad MF et al in 2009 investigated the effect of tooth preparation burs and luting cement types on marginal fit of extracoronal restorations and concluded that, marginal fit of complete cast crowns is influenced by tooth preparation surface characteristics hence, tooth preparation refined with finishing burs favours the placement of restoration with smallest marginal discrepancy, during cementation.1
6.3 OBJECTIVES OF THE STUDY:
To evaluate the effect of three different preparation burs i.e. fine, medium and coarse grit diamond burs on the retention of full cast crowns.
To evaluate the retention of full cast crowns cemented with three different cements, i.e. zinc phosphate, glass ionomer, adhesive resin cement.
To find out which preparation bur and which luting cement used in this study gives maximum retention for the full cast metal crowns.
MATERIALS AND METHODS:
Ninety extracted, intact human premolar teeth of similar size will be collected and stored in distilled water at room temperature. The roots of all teeth will be notched for anchorage with a separating disk. Each tooth will be aligned vertically in an individual epoxy resin die within 2mm of the cementoenamel junction. A dental surveyor will be used to position the long axis of each tooth parallel.10
Teeth will be randomly assigned to three groups of 30 each according to the rotary instruments, i.e. group A, group B, and group C.
The teeth will be prepared to receive complete cast crowns with the use of
1.  Coarse grit diamond bur
2.  Medium grit diamond bur
3.  Fine grit diamond bur.
While preparing the teeth to receive the crown,
Group A- 30 teeth will be finished with coarse grit diamond bur
Group B- 30 teeth prepared with coarse grit will be finished with medium grit diamond bur
Group C- 30 teeth prepared with coarse and medium grit will be finished with fine grit diamond bur.
Tooth preparation will be done by preparing the occlusal surface flat to the depth of 1.5mm for each preparation with 4mm axial height. Convergence angle of 6 degrees with a chamfer margin circumferentially.
Once the crown preparation will be complete, impressions will be made of the prepared teeth with a polyvinyl siloxane material and the impressions will be poured with type IV die-stone.10
Wax pattern for crowns will be prepared. Each stone die will be designated with a code number corresponding to the tooth from which it will be derived, so that each pattern could be identified. The patterns will be invested with phosphate bonded investment material and cast. Castings will be recovered from the investment cleaned and finished.1,2,10
crowns
The prepared crowns in each group will be randomly subdivided into three subgroups of 10 each for the three luting cements selected for this study:
1.  Zinc phosphate cement,
2.  Glass ionomer cement and
3.  Adhesive resin cement.
Retention will be evaluated by measuring the tensile load required to dislodge the artificial crowns from tooth preparations with an Universal testing machine.2,10,11
7.1 STATISTICAL ANALYSIS :
The readings obtained will be collected and statistically analyzed.
7.2 Does the study require any investigations or interventions to be conducted on patients or other humans or animals? If so please describe briefly.
No
Has ethical clearance been obtained from your institution in case of 7.2?
Not Applicable
LIST OF REFERENCES:
1.  Ayad MF. Effect of tooth preparation burs and luting cement types on the marginal fit of extracoronal restorations. Journal of Prosthodontics 2009;18: 145-151.
2.  Rajkumar K et al. Effect of axial groove and resin luting cements on the retention of complete cast metal crowns. Dental Res J 2009;6(1):39-45.
3.  Narula S et al. Retention in conventional fixed partial dentures: a review. Journal of Clinical and Diagnostic Research 2011;5(5): 1128-1133.
4.  Tuntiprawon M. Effect of tooth surface roughness on marginal seating and retention of complete metal crowns. J Prosthet Dent 1999;81:142-179.
5.  Siegel S and Fraunhofer JA. Cutting efficiency of three diamond bur grit sizes. JADA 2000;131:1706-1710.
6.  Medić V. et al. In vitro evaluation of microleakage of various types of dental cements. Srp Arh Celok Lek 2010;138(3-4):143-149.
7.  Ladha K and Verma M. Conventional and contemporary luting cements: an overview. J Indian Prosthodont Soc 2010; 10(2):79–88.
8.  Worley JL, Hamm RC, and Fraunhofer JA. Effect of cements on crown retention. The Journal of Prosthetic Dentistry 1982;48(3):289-291.
9.  El-Mowafy OM et al. Retention of metal ceramic crowns cemented with resin cements: effect of preparation taper and height. J Prosthet Dent 1996;76:524-529.
10.  Ayad MF, Rosenstiel SF, And Salama M. Influence of tooth surface roughness and type of cement on retention of complete cast crowns.J Prosthet Dent 1997;77:116-21.
11.  Yim NH et Al. Effect of dentin desensitizers and cementing agents on retention of full crowns using standardized crown preparations. J Prosthet Dent 2000;83: 459-65.
9 / SIGNATURE OF CANDIDATE / (MOKSHADA M. BADADARE)
10 / REMARKS OF THE GUIDE
11

12 / NAME AND DESIGNATION
(IN BLOCK LETTERS)
11.1GUIDE
11.2 SIGNATURE
11.3 CO-GUIDE (IF ANY)
11.4 SIGNATURE
11.5 HEAD OF THE DEPARTMENT
11.6 SIGNATURE
REMARKS OF THE PRINCIPAL
12.1 SIGNATURE / DR. SUDHAKARA BHAT.G M.D.S
PROFESSOR AND HEAD
DR. SUDHAKARA BHAT.G M.D.S
HEAD OF THE DEPARTMENT
DEPARTMENT OF PROSTHODONTICS, SRI HASANAMBA DENTAL COLLEGE AND HOSPITAL, HASSAN – 573201

DR. S. RAVINDRA M.D.S.

PRINCIPAL,

SRI HASANAMBA DENTAL COLLEGE AND HOSPITAL,
HASSAN – 573201