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Paper Information

Journal:   JOURNAL OF ISLAMIC DENTAL ASSOCIATION OF IRAN (MAJALLAH-I-DANDANPIZISHKI)   FALL 2013 , Volume 25 , Number 3 (88); Page(s) 269 To 274.
 
Paper: 

THE EFFECT OF FINISHING AND POLISHING TIME ON MICROLEAKAGE OF COMPOSITE RESTORATIONS

 
 
Author(s):  MIRZA KOUCHAKI BOROUJENI P.*, BAREKATAIN M., FATTAHI P., FATEMI A., ZAHRAEI L., SHARAFI A., FAZELI F.
 
* DEPARTMENT OF OPERATIVE DENTISTRY, SCHOOL OF DENTISTRY, ISLAMIC AZAD UNIVERSITY, KHORASGAN BRANCH. ESFAHAN, IRAN
 
Abstract: 

Background and Aim: Composite resins require time to complete their polymerization. This process usually reaches its maximum rate after 24 hours. On the other hand, immediately after restoration, water sorption results in hygroscopic expansion of composite resins and the mentioned two factors usually reachequilibrium after a week. Considering the effect of mentioned processes on the micro leakage of composite restorations, the purpose of the present study was to evaluate the effect of finishing and polishing time on the mean micro leakage of composite restorations.
Materials and Methods: In this in-vitro experimental study, 60 sound human premolar teeth were selected. A standard Class V cavity was prepared measuring 1.5 mm in depth, 3 mm in width and 2 mm in length on the buccal surface of each tooth and incrementally restored with composite resin. Next, the teeth were randomly divided into 4 groups. The teeth in groups I, 2, 3 and 4 were finished and polished immediately, 15 min, 24 h and one week after storage in distilled water at 37oC, respectively. Specimens in each group were subjected to 500 thermal cycles. The teeth were then coated with adhesive wax and nail varnish and immersed in 2% fuchsin solution for 24h. The specimens were washed and each sample was longitudinally sectioned in half by a diamond saw. Both halves were evaluated in terms of dye penetration under a stereomicroscope at 28X magnification. For each sample, the section with greater degree of microleakage was selected. Kruskal Wallis test and Mann Whitney U test were used for data analysis with a 99.1 % confidence interval.
Results: The lowest mean micro leakage was observed in the occlusal margin of group 3 teeth; while the highest mean micro leakage belonged to the occlusal and gingival margins of teeth in group 2. A significant difference was noted between the 4 groups in occlusal margin micro leakage (P<0.009). However, no such difference was found in gingival margin.
Conclusion: This study showed that the finishing and polishing timewas effective on the mean microleakage in the enamel margin of composite restorations. The best time of finishing and polishing was 24h after the restoration. Time offinishing and polishing had no effect on micro leakage in dentin margins of restorations.

 
Keyword(s): COMPOSITE RESINS, POLISHING, MICROLEAKAGE
 
References: 
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