Effect of Chitosan pretreatment of the demineralized dentin surface on the durability of resin dentin bonding. An in vitro study

Abstract: the aim of this study was to evaluate the effect of pretreatment of the demineralized dentin surface with Chlorohexidine (CHX), Chitosan (Ch), riboflavin (RF) and Chitosan/riboflavin (RF) combination on the shear bond strength and short-term bond durability with total etch adhesives. Fifty sound extracted human permanent molars were used in this study. The teeth were embedded in plastic tube containers and a flat dentin surface was then prepared by grinding the occlusal enamel exposing superficial dentin surfaces. Specimens were etched for 15 sec with 35% phosphoric acid and were then randomly divided into five groups (10 teeth each), one control group and four experimental groups according to the surface pretreatment (Chlorohexidine, Chitosan, riboflavin and Chitosan/riboflavin combination). This is followed by application of total etch adhesive system and resin composite restoration. The resin composite samples were then divided to be stored either for 24 h or 6 months in distilled water at 37 C followed by shear bond strength testing using Instron Testing Machine. The data were analyzed using ANOVA test. The results revealed that, pretreatment of the demineralized dentin surface with CHX, Ch, RF, and Ch/RF 1:1 significantly improved the shear bond strength mean values at both 24 h and 6 months storage in distilled water compared to the control group. Within control group, significant reduction in shear bond strength mean values were found after 6 months storage in distilled water compared to the baseline measurements at 24 h. The immediate pretreatment of the demineralized dentin with collagen cross linkers could be safely recommended as an effective chairside procedure to improve shear bond strength of resin composite to dentin.