Bioglasses do not interfere with the adhesion of self-etching systems

Objectives: The aim of this study was to evaluate the strength of dentine pre-treated with different formulations of bioglass. The ultra-morphology and micropermeability of the interfaces were evaluated using confocal microscopy (CLSM). Methods: Dentine crowns were bonded using two different self-etching systems (DBAs: S3 Bond, Kuraray Corp., Japan or G-Bond, GC Corp., Japan) after receiving one of five different dentine surface treatments: (1) Bioglass air-abrasion BAG with deionised water (H2O); (2) BAG with 10% PAA-powder; (4) BAG with 40% PAA-powder; (5) 320 SiC abrasive-polished dentine . A 5mm incremental build-up was made using Filtek Z250 (3MESPE) and photo-cured for 30 seconds. Microtensile bond strengths (MTBS) were performed and results compared statistically using SPSS 16.0 (SPSS Inc., Chicago, IL, USA). As the normality of the data (Shapiro–Wilk W-test) and equality of the group variances (Levene test) were valid, the statistical differences between groups were identified by two-way ANOVA; adhesive system and dentine surface were considered as independent variables. Fisher's least significant difference (LSD) test isolated and compared the significant differences between groups. Statistical significance level was set at α=0.05. Additional dentine surfaces were conditioned and bonded as previously described. These were prepared for a pulpal-micro-permeability confocal microscopy study, sectioned, polished and observed using CLSM. Results: Mean bond strength was affected by the adhesive system (P<0.001) but not those between adhesive system/dentine treatment (P > 0.05).S3 Bond showed higher (P<0.001) results compared to those for the G-Bond. No statistical differences (P<0.001) were found between the different dentine pre-treatments performed in each group. The lowest micro-permeability was observed within the bonded bioglass air-abraded dentine. Conclusions: The bioglasses used in this study do not interfere with the adhesion of middle-acidic self-etching systems. However, self-etching adhesives containing the 10-MDP functional monomer may encourage a stronger immediate adhesion when bonded to bioglass air-abraded dentine.