Comparison of the Effect of Dentin Bonding, Dentin Sealing Agents on the Microleakage of Provisional Crowns Fabricated with Direct and Indirect Technique-An Invitro Study.
BACKGROUND
Postoperative sensitivity after temporization is a common complaint in Fixed Partial Denture patients. It is caused by weak and ill fitting temporary restorations which results in microleakage. This can be controlled by providing good temporary restorations and by coating the exposed dentinal tubules of the prepared tooth with dentin bonding agent or dental varnish.


OBJECTIVE
The purpose of the study was to determine the effect of dentin-bonding, dentin sealing agents on the microleakage of temporary crowns made by tooth colored auto polymerizing resin fabricated with direct and indirect technique.


METHODS
Thirty premolar and molar human teeth were collected which were extracted recently was used for the study. The teeth were marked and divided into 3 groups each containing 10 nos. They were individually mounted with self-cure acrylic resin. It was then mounted on a milling machine and crown preparations done. Temporary crowns were fabricated by direct and indirect method with two types of materials. In group A (Control group), the temporary crowns fabricated with both direct and indirect method were cemented directly with temporary luting cement. In group B dentine-bonding agent (solobond M) was applied once to the prepared surface of each tooth specimen before the cementation of temporary crowns where as in case of group C a single layer of dental varnish is applied prior to crown cementation. The entire specimens were immersed in 1% methylene blue and allowed to undergo thermal treatment. It was then sectioned in a hard tissue microtome. Each section was evaluated for dye penetration into the dentin tubules by comparing it with a visual scale.


METHODS
SPSS Version 13 software was used for non-parametric data analysis by a qualified statistician. P-values less than 0.05 (p-value<0.05) were considered to be statistically significant.


RESULTS
Group B (Dentin Bonding Agent) specimens cemented with crowns fabricated in direct technique showed the least amount of microleakage when compared with group A and group C. Group C (Dental Varnish) specimen showed comparatively more amount of microleakage than that of group B. Group A (control group) specimens showed the maximum amount of microleakage.


CONCLUSIONS
The application of a single layer of Dental varnish appears to be of no significant benefit when compared to crowns cemented with the application of Dentin bonding agent on the tooth surface. The application of a single layer of Dentin bonding agent (Solobond M) and temporary crowns fabricated with direct technique may be of some benefit for crown preparations as an interim measure prior to the luting of final crown.
Senior Lecturer, Department of Prosthodontics, Chettinad Dental College , Chennai, India .
Peter
P
John
Professor and HOD, Department of Prosthodontics, SRM Dental College , Ramapuram, Chennai, India .
B
B
Muthukumar
Former Principal and HOD, Department of Prosthodontics, SRM Dental College , Ramapuram, Chennai, India .
M Vasantha
MV
Kumar
Dentin-bonding agents; Hybrid layer; Thermal treatment