Comparing microleakage and layering methods of silorane-based resin composite in class V cavities using confocal microscopy: An in vitro study.

AIMS: This in vitro study compared the effects of different layering techniques on the microleakage of silorane-based resin composite using confocal laser scanning microscope.

MATERIALS AND METHODS: Forty caries free premolars extracted for orthodontic reasons were used. A class V cavity was prepared on the buccal surface in each of the premolars, with the gingival margin of the cavity being 1 mm above cementoenamel junction. The cavities were restored with a silorane-based resin composite (Filtek(™) P90 Silorane Low Shrink Restorative, 3M ESPE) using two different layering techniques - split incremental and oblique layering technique. All samples were subjected to 1000 thermal cycles of 5°C/55°C in water with a 30 second dwell time, and after the procedure, the teeth were immersed in 0.6% aqueous rhodamine dye for 48 hours. Sectioned samples were examined under a Confocal Fluorescence Imaging Microscope (Leica TCS-SP5, DM6000-CFS) at 10× magnification, and microleakage scores were analyzed statistically using paired "t" test and Mann-Whitney test. Width of interface between the tooth surface and resin composite was measured using a digital scale (Snagit digital scale).

RESULTS: Microleakage was seen along the entire perimeter of restoration irrespective of the layering technique used. The microleakage score was same in both the groups. Statistical analysis of width of interface showed significant difference between the two layering techniques. The width was significantly less in split incremental technique, indicating less polymerization shrinkage.

CONCLUSIONS: This in vitro study showed that the silorane-based resin composite shows microleakage irrespective of the layering technique used for class V cavities. However, this problem can be minimized significantly by using split incremental technique for restoration of class V lesions.