Evaluation of adhesive interface degradation on bond strength with different adhesive applications.

EVALUATION OF ADHESIVE INTERFACE DEGRADATION ON BOND STRENGTH WITH DIFFERENT ADHESIVE APPLICATIONSThe purpose of this study was to evaluate the influence of 2% Chlorhexidine (CHX), double adhesive layer (DA), extra hybrophobic resin layer (HL) applications proposed to decrease adhesive interface degradation on the microtensile dentin bond strength of simplified adhe- sive systems.Two-step etch&rinse system Adper Single Bond2 [SB] and one-step self- etch system Clearfil S3 Bond [S3] were tested, two-step self-etch adhe- sive system Clearfil SE Bond [SE] was used as control. Seventy-two extracted human third molars dentin occlusal surfaces were exposed by grinding with 600-grit SiC paper. The adhesives were applied according to the manufacturer’s directions [MD], or with 2% Chlorhexidine [CHX] application or double application of the adhesive layer [DA] or following the manufacturer’s directions extra hydrophobic resin layer coating [HL]. After applying the adhesive resins, composite crowns were built up in- crementally. After 24-h water storage, the specimens were serially sec- tioned in“x”and“y”directions to obtain bonded sticks of about 1.0 mm2 to be tested immediately [IM] or after 6 months of water storage [6M] at a crosshead speed of 0.5 mm/min. The data from each adhesive was ana- lyzed by Three-way ANOVA (adhesive system, mode of application vs. storage time) and Tukey’s test (p = 0.05).After 6-months, all adhesives bond strength reduced significantly (p<0.01). SE showed the highest bond strength while no difference was found between SB-MD and S3-MD (p>0,05). Higher bond strengths values were observed for CHX, DA and HL applications, however HL and DA were significantly different from the manufacturer’s directions (p<0.01) and HL bond strength was the highest (p<0.01). When com- pared the adhesive systems only DA and HL application for S3 was significantly higher (p<0.01).The application of DA and HL can improve the resin-dentin bonds and decrease the adhesive interface degradation