Microleakage of Silorane-based Resin Composite in Comparison with Methacrylate-based Composite in Class II

Introduction: This in vitro study aimed to evaluate the effect of different monomer systems on microleakage in class II composite open sandwich restorations with and without a separating agent placed between the nanofilled resin modified glass ionomer and the resin. Materials and methods: Class II cavity preparations were prepared in maxillary premolars (n = 240) and the cervical limit of the proximal box was below the cementoenamel junction. Group 1 was restored with silorane-based composite and group II was restored with methacrylate-based composite. All specimens were subjected to thermocycling and examined for microleakage after in 50% silver nitrate solution. The recorded results of dye penetration were statistically analyzed using Chisquare test. Results: Methacrylate-based composite (Filtek Z 350, 3M, St Paul, MN, USA) exhibited the highest dye penetration and silorane-based composite (Filtek P90 Low Shrink Posterior Restorative, 3M, St Paul, MN, USA) showed the lowest dye penetration among the restorative materials. However, specimens with separating agent showed almost no leakage between the RMGIC and tooth interface. Conclusion: Forces of polymerization shrinkage are stronger than the bond between glass ionomer cement and tooth interface and the use of silorane technology in open sandwich restoration will decrease microleakage and improve clinical performance.