A double-blind randomized clinical trial of a silorane-based resin composite in class 2 restorations: 18-month follow-up.

PURPOSE

To compare the clinical performance of a silorane-based with a methacrylate-based restorative system in class 2 restorations after an 18-month follow-up.

METHODS

This randomized, double-blind and controlled study included 33 subjects receiving 100 direct resin composite restorations that were completely randomized to silorane-based group (Filtek P90/Silorane System Adhesive - 3M ESPE) or methacrylate-based group (Filtek P60/Adper SE Plus - 3M ESPE). The restorative system was determined by chance using a coin toss until 50 units for each group were completed. Each subject contributed with one to seven restorations. A single operator performed all of the restorative procedures. Two calibrated examiners (kw > or = 0.7) assessed the restorations at baseline and after 18 months according to modified United States Public Health System (USPHS) criteria. The data were analyzed with Mann-Whitney U-test, Wilcoxon signed rank and Kaplan-Meier survival curves (alpha = 0.05).

RESULTS

After 18 months, 88 restorations were evaluated, and five unacceptable restorations were observed. Proximal contact loss was the main reason for failure (three) followed by composite fracture (two). The marginal integrity of the silorane-based group was significantly worse than that of the methacrylate-based group (P= 0.035). Comparing baseline to 18-month evaluations, the silorane-based group showed significant differences for marginal discoloration, marginal integrity and surface texture (P < 0.05); and the methacrylate-based group differed significantly for marginal discoloration and surface texture (P < 0.05). Combined survival rate for both groups together was 95%. No statistically significant difference was found between methacrylate-based (98%) and silorane-based (92%) overall survival rate (Log rank test; P = 0.185).