An in vitro evaluation of microleakage in class v preparations restored with Hybrid versus Silorane composites

Aim: To compare the difference in microleakage values using conventional and new low-shrink Silorane composites using the dye penetration method. Background: With improvement in adhesive technology, problems associated with composites have been largely overcome. However, microleakage due to polymerization shrinkage still remains a challenge. New Silorane-based composites are alleged to have less than 1% polymerization shrinkage, which would potentially decrease the microleakage, and hence, resolve this longstanding issue. Materials and Methods: The teeth were randomly divided into three groups (A,B, and C). Group A was restored with conventional composite (Valux ^TM Plus), with a total-etch protocol, Group B was restored with conventional composite, with a self-etch protocol, and group C were restored with a silorane-based composite (Filtek TMP90). Thermocycling at 200 cycles between 5 and 55°C 2°C with a dwell time of 60 seconds was conducted. The teeth were stained with methylene blue dye and then sectioned and viewed under a dissection microscope, afer which the microleakage was evaluated. Results: The interexaminer reliability was evaluated using the kappa score, which was acceptable (61-78%). The total-etch group performed statistically and significantly better (P < 0.001) at the occlusal margin and was marginally and statistically significant (P = 0.05) at the gingival margin compared to the self-etch conventional and Silorane groups. Conclusions: The Silorane composite did not perform better than the conventional composites, however, it may have its uses and requires further research.