Microtensile bond strength of universal adhesive

Abstract

Purpose Evaluation of the effect of adhesive mode and CHX application on microtensile bond strength of the universal adhesive to caries-affected dentin. Material and methods Twenty human permanent molars with simple occlusal caries were collected. Teeth were randomly divided into two main equal groups according to adhesive mode (Etch and rinse {ER} or Self etch {SE}). Each group was subdivided into two subgroups according to CHX pretreatment with four subgroups obtained; A1: ER, A2: ER+CHX, B1: SE and B2: SE+CHX. Occlusal enamel was trimmed to obtain flat dentin surface composed of CAD surrounded by sound dentin. Universal adhesive was applied according to adhesive mode and CHX application followed by composite resin build-up. Specimens were stored in 5% citric acid for 3 months then subjected to 5000 cycles of thermocycling. Then, all specimens were sectioned into slabs and then bars with cross-section 0.9 ± 0.01 mm2. Bars with CAD were selected for μTBS test until failure. Failure modes analysis was determined using stereomicroscope. Results Both adhesive modes with and without CHX application tested on CAD presented similar μTBS (P > 0.05). Subgroup A1 recorded the highest μTBS followed by Subgroup B1 which is statically nonsignificant (P = 0.112). No statistically significant difference was found when comparing the effect of CHX on bond strength for both Subgroups A2 and B2 when compared with control groups (A1 and B1). Predominance of adhesive/mixed failure was noticed for all subgroups. Conclusion ER approach could not improve bonding performance of universal adhesives to CAD. CHX did not interfere with bond strength to CAD.