Effects of dentin disinfectants on the shear bond strength of all-ceramics to dentin

This study investigated the effect of dentin disinfectants on the shear bond strength of all-ceramic restorations luted with two different dual-polymerizing systems to dentin. Dentin disinfectants chlorhexidine gluconate-based Concepsis and benzalkonium chloride-based Tubulicid Red were applied in combination with Variolink 2 and Resilute. The buccal surfaces of non-carious extracted human premolars were flattened to expose dentin and subsequently polished with 600-grit wet silicon carbide paper. Each dual-polymerizing luting system had two test groups and a control group. Dentin from the test groups was first treated with dentin disinfectants, then the all-ceramic restorations were luted with dual polymerizing systems. The dentin without disinfectant application and ceramic restoration was used as a control. After the all-ceramic samples were luted to all treated surfaces, the specimens were thermocycled and tested for shear bond strength until failure. Analysis of the fractured dentin surfaces was performed using Optical Microscope-Nikon ECLIPSE ME 600 (Nikon Co, Tokyo, Japan) at between 10x and 1000x magnifications and the images were analyzed with Image Analyzer LUCIA 4.21 (Nikon Co). The data were analyzed with one-way ANOVA and Duncan test at a significance level of p<0.05. Application of the two dentin disinfectants increased the shear bond strength of both the Variolink 2 and Resilute systems, but this increase was statistically significant only in Tubulicid Red treated specimens (p<0.05). Surface analysis showed that all the specimens showed the adhesive failure mode between the dentin and composite luting agent interface.