Effect of thermocycling and varying polymerization techniques on the restorative interface of class V cavities restored with different composite resin systems

BACKGROUND: To evaluate marginal microleakage of two composite resins - a methacrylate- and a silorane-based submitted to different polymerization techniques and thermocycling. MATERIAL AND METHODS: Ninety-six class V cavities were prepared in sound human molars and restored under different polymerization and thermocycling regimens. The adhesive systems employed were Adper Scotchbond Multipurpose and Filtek P-90 for cavities restored with Z250 and P-90. The specimens were restored with Z250 or P-90, and divided into 3 subgroups with different polymerization techniques. The data were analyzed by Three way Analysis of Variance Test (p<0.05). RESULTS: Micro infiltration lower scores were found in groups which were used silorane-based resin with significant statistical difference compared with the specimens restored with methacrylate-based resin, independently of polymerization type used and thermocycling (P>0.001). CONCLUSIONS: Silorane-based composite resins present lower marginal microleakage values when compared to methacrylate-based composites resins. Key words:Composite resin, microleakage, polymerization.