The influence of acid etching or chitosan dentin surface treatments on dentin wettability and shear bond strength of self- etch adhesives

The aim of the study was to investigate the influence of dentin surface preparation with acid etching or chitosan treatment on dentin wettability and shear bond strength to resin composite using self-etch adhesive.
Methods: Fifteen human sound extracted third molars were used in the study. Dentin disks were cut from the crown for evaluation of dentin wettability, and the remaining part of the crown was used for the shear test. Dentin discs were divided randomly into 3 groups (n=5) treated as follow: G1: control, G2: acid etched with 32% phosphoric acid, and G3: treated with Chitosan for 60 s. Contact angle of treated dentin surfaces with a self-etch single bond universal adhesive was measured using a drop shape analyzer. The remaining crowns used for shear bond strength test (SBS) were divided randomly into three groups (n=5) and prepared in the same manner used for wetting evaluation. Nano-hybrid composite material were bonded to treated dentin surface using self-etch adhesive. Samples were subjected to SBS testing in a universal testing machine.
Results obtained, showed statistically significant lower contact angle after chitosan treatment of dentin surfaces as compared to control and acid etched groups (p<0.05). On the other hand, both acid etching and chitosan treatment of dentin surfaces resulted in a statistically significant lower SBS compared to control untreated group (p<0.05).
Conclusion: Bonding to dentin using self-etch adhesive is best achieved with direct application of adhesive resin on untreated dentin surface.