Evaluation of Microleakage in Class V Cavities Filled with Methacrylate-based versus Siloranr-based Composites

Statement of Problem: Despite the increasing demand for tooth-colored restorations in dentistry, polymerization shrinkage and marginal microleakage still remains a problem. Objectives: The purpose of the present study was to evaluate microleakage in three different resin composites, P90, Z250 and Z250 XT, in class V cavity of permanent human premolars. Materials and Methods: Standardized class V cavities were prepared on the buccal surface of 45 extracted human premolars. The occlusal margins of cavities were prepared at the enamel and gingival margins extending 1mm below the ce-mentoenamel junction. The teeth were randomly assigned into three groups (N=15) and preparations restored with three different composites following the manufacturer instructions: Group A, Filtek Z250 (microhybrid composite) with Adper Single Bond total etch adhesive system; Group B, Filtek Z250 XT (nanohybrid) with Adper Single Bond total etch adhesive system;Group C, Filtek P90 (silorane) with its self-etch adhesive system (P90 system adhesive). Its adhesive system (P90 system adhesive). The teeth were then subjected to thermal cycles (1000 cycle, 5° and 55°C ± 2°C) with a dwell time of 30 seconds, and immersed in 2% basic fuchsine for 24 hours. Longitudinally sectioned teeth were examined under the stereomicroscope. Kruskal-Wallis and Mann-Whitney U test at 95% significance level were used. Results: Filtek Z250XT showed significantly higher microleakage than the other two composites (p < 0.001). However, there was no statistically significant difference between P90 and Filtek Z250 (p=0.217). Conclusions: Although all of the restorative systems had microleakage, silorane-based composite showed less microleakage compared to two other methacrylate-based composites.