evaluation of enamel and dentinal microleakage in class ii silorane-based and methacrylate-based resin composite restorations using specific and nonspecific adhesives

Objectives: the aim of this study was to evaluate enamel and dentinal microleakage in class ii cavities restored with silorane- and methacrylate-based resin composites using specific and nonspecific adhesives. materials and methods: thirty-six caries-free human premolars were used. two class ii cavities were prepared on each tooth. the gingival floor was set at 1 mm above (on the mesial surface) and at 1 mm below (on the distal surface) the cementoenamel junction (cej). the samples were randomly divided into four groups, and the cavities were restored with a methacrylate-based composite (filtek™ p60) and a silorane-based composite (filtek™ p90) with specific and nonspecific adhesives. microleakage was tested using a standardized dye penetration method. all samples were examined under a stereomicroscope, and microleakage scores were statistically analyzed using kruskal-wallis and mann-whitney-u tests. one sample from each group was examined under a scanning electron microscope (sem) to determine the bonding area. results: no significant difference was found between the groups in terms of the enamel microleakage (p=0.086). there was a significant difference between the groups with regard to dentinal microleakage (p=0.003). no significant reduction in microleakage was observed in groups restored with filtek™ p90 composite using its specific adhesive compared to those restored with filtek™ p60 composite using its specific adhesive (p=0.626). conclusions: the results indicated that the application of methacrylate- and silorane-based composites with specific or nonspecific adhesives had no impact on enamel microleakage, but it affected dentinal microleakage, and specific adhesives showed less microleakage. it seems that a phosphate-methacrylate-based intermediate resin is required to bond dimethacrylate adhesive to silorane-based composites.