Bonding strength of silorane-based composite to Er-YAG laser prepared dentin

Abstract

The aim of this study was to investigate the shear bond strength of two adhesive systems to laser-irradiated dentin compared with their shear bond strength to bur-cut dentin as well as to evaluate the influence of composition and type of dental materials on shear bond strength. Thirty-two dentin specimens prepared from human third molars were divided into two groups and conditioned either with an Er:YAG laser machine or with a carbide bur. Two different adhesive systems (Silorane System Adhesive and Single Bond) were evaluated in the present study. After light curing of the adhesives, a Teflon mold was placed over the ring with the dentin sample and filled with the composite resins Filtek Silorane and Filtek Z250 combined with the appropriate adhesive systems. This procedure resulted in 32 cylindrical specimens (3mm in diameter, 4mm in height) being bonded to the dentin. The specimens were stored for 24h at 37°C in water and then were thermocycled. Shear bond strength testing was conducted by means of a universal testing machine and failure patterns were analyzed under a stereomicroscope. Two specimens of each fracture failure mode were randomly selected for SEM evaluation. Filtek Silorane present no statistically significant difference in shear bond strength compared with Filtek Z250, regardless of dentin treatment (p > 0.05). Additionally, the self-etching Silorane Adhesive System exhibited as good adhesive values as etch-and-rinse Single Bond, independently on dentinal substrate (p > 0.05). Specimens prepared by Er:YAG laser appear as receptive to adhesive procedures as conventional carbide bur-cut specimens (p > 0.05).