Chewing Simulation of Silorane and Methacrylate Restorations

Objectives: The goal of this study was to compare the marginal integrity of a cationic curing Silorane composite with a polymerization shrinkage of <1% in combination with its self-etching system adhesive with conventional methacrylate systems before and after chewing simulation.

Methods: Standardized MOD cavities were cut in human molars with one proximal box limited within enamel (1-1.5mm above CEJ) and the other extending into dentin (1-1.5mm below CEJ). Pulpal pressure (25mmHg) was simulated with a horse serum / PBS solution mixture. Teeth were randomly assigned  to 3 groups (n=5) and restored immediately after preparation with the following direct composite restorations according to the manufacturers' instructions: Filtek Silorane / Silorane System Adhesive (SIL, 3M ESPE), QuixFil / Xeno III (QXF, Dentsply),  Tetric EvoCeram / AdheSE (TEC, Ivoclar-Vivadent). Subsequently, specimens were subject to chewing simulation involving simultaneous thermal (5°C/55°C, 1550 cycles, 3min/cycle) and mechanical load cycling (50N, 480000 cycles, 0.6s/cycle). Before and after chewing simulation, epoxy replica (Epofix, Struers) were taken and marginal integrity was analyzed by SEM (LEO 1530 VP, 200x).

Results: The table shows the mean percentages of total continuous margins (enamel and dentin) before and after chewing simulation. Standard deviations are given in parentheses. All data were analyzed by ANOVA and multiple comparisons using the Tukey test (p<0.05). Means with the same superscripted letters were not statistically different.

Conclusion: The combination Filtek Silorane  / Silorane System Adhesive resulted in a significantly higher percentage of continuous margins before and after chewing simulation than the methacrylate systems tested.