An in vitro evaluation of microleakage of resin based composites bonded to chlorhexidine-pretreated dentin by different protocols of a universal adhesive system

This study compared microleakage of different resin based composite (RBC) materials bonded to dentin, after chlorhexidine (CHX) application, by different adhesion protocols of a universal adhesive system. Class V cavities were prepared on the buccal and lingual surfaces of 40 premolar teeth. The “etch-and-rinse” technique of a universal bond adhesive system (Single Bond Universal Adhesive) was used on buccal preparations, while the “self-etch” protocol was used on the lingual surfaces. Two RBCs, one bulk fill (Filtek Bulk Fill [FBF]) and one conventional (Filtek Z350 XT [Z350XT]), were used. Teeth were divided into two groups of 20 teeth each, 10 per each RBC (n = 10): (1) control; and (2) pretreatment with 2% CHX. For FBF groups, teeth were restored with a single increment; however, for Z350XT, a layering technique was used. Teeth were aged by thermo-cycling and prepared for microleakage testing. Dye penetration was evaluated and scored from 0 to 4. Data were analyzed at a significance level of P 0.2). When the “self-etch” protocol of the universal adhesive system was used, dentin microleakage was not affected by CHX-pretreatment when teeth were restored with bulk fill or conventional RBCs. In the “etch-and-rinse” protocol, CHX application improved the marginal seal before restoration with bulk fill material. However, in the absence of CHX, the “etch-and-rinse” protocol negatively affected marginal integrity.