Microleakage and microtensile bond strength of silorane-based and dimethacrylate-based restorative systems

To evaluate the microleakage and bond strengths (microTBS) of silorane-based (SBC) and dimethacrylate-based (DBC) restorative systems. The null hypotheses are: 1) there is no difference in microleakage between the resin composites and the adhesive systems tested at the enamel and dentin margins; 2) there is no significant difference in microTBS between the composite restorative systems using self-etch and etch-and-rinse adhesive versions.

Microleakage: Class V cavity preparations with cervical margin in dentin were performed on pristine extracted human molars and were randomly distributed among the following three groups: Group 1-DBC/etch-and-rinse adhesive system (Filtek™ Supreme Ultra/Adper™ Single Bond Plus, 3M ESPE, www.3MESPE.com); Group 2-SBC/self-etch adhesive (Filtek LS Low Shrink Posterior Restorative System/LS self-etch adhesive, 3M ESPE); Group 3-DBC/self-etch adhesive (Filtek Supreme Ultra/ Adper Easy Bond Self-Etch, 3M ESPE). Restorations were thermocycled and immersed in 0.2 percent methylene blue dye for 24 hours. Samples were assessed visually under 10x magnification; microTBS: Bond sticks (0.9 mm2) were prepared from each group and tested on a universal testing machine.

The Kruskal-Wallis test revealed no significant difference in microleakage among the experimental groups at the enamel margin (P=0.191). At the dentin margins, silorane/self-etch restorative system showed significantly less leakage than the dimethacrylate/etch-and-rinse restorative system (P=0.008). Tukey's B rank order test showed that the dimethacrylate/etch-and-rinse restorative system presented the highest microTBS.

SBC/self-etch system showed less microleakage at the dentin margins, while DBC/etch-and-rinse system presented higher bond strength.