Dentin bonding durability of self-etch adhesive pre-treated with chlorhexidine 2%

Objectives: The aim of this study was to evaluate the effect of 2% chlorhexidine digluconate on bond strength of a self-etch adhesive applied to sound (SD) and caries-affected dentin (CAD). It is hypothesized that CHX does not have a detrimental effect on the bond strength to sound and caries-affected dentin, as well as that CHX may decelerate the mechanical degradation of resin-dentin bonds over time. Methods: Third molars were extracted and the occlusal enamel was removed to expose a flat dentin surface, where the CAD was surrounded by SD. The CAD and SD surfaces were dried with oil/water-free air and re-hydrated with 2 wt% chlorhexidine digluconate (CHX). After a dwell time of 60s, solution excess was removed with absorbent paper and the dentin surfaces were bonded with a self-etch adhesive. Composite build-up was performed with Z250 and stored in phosphate-buffered saline solution (PBS, pH 7.4) at 37°C for 7 days. After this period, the restored teeth were longitudinally sectioned across the bonded interface to produce a series of 0.8mm² beams. Part of those specimens was immediately tested on microtensile. The remaining specimens were stored in PBS at 37°C for one year and then tested under the same protocol. Results: Data were submitted to ANOVA and Tukey's test (p = 0.05). There was a significant difference on initial bond strength between CAD and SD. After one year the specimens pretreated with CHX had similar bond strength and there was no difference between SD and CAD. Conclusion: The use of CHX may preserve the resin-dentin bonds.