Methods: Occlusal surfaces of 18 extracted human non-caries third molar teeth were ground flat to expose dentin and polished with 600-grit wet silicon carbide paper to standardize the smear layer. Teeth were randomly divided into six groups (n=12), desensitizers and dentin bonding agents applied according to the manufacturers’ instructions respectively. Group 1)Teethmate desensitizer(TD)(Kuraray)+Clearfil S3 Bond Plus(CS3)(Kuraray), 2)TD+Adper Single Bond 2(SB)(3M/ESPE), 3)Gluma(Heraus Kulzer)+CS3, 4)Gluma+SB, groups 5 and 6 were the control groups which haven’t applied any desensitizers and CS3 and SB were applied respectively. 5-mm high resin composite blocks (3M/ESPE Filtek Z250) were incrementally applied on the occlusal dentin surfaces. The specimens were serially sectioned perpendicular to the adhesive layer to obtain 1 mm² bounded sticks for microtensile test. Then, each stick was submitted to the microtensile test performed at a 1 mm/min crosshead speed. Data was analyzes using ANOVA and Student t test(p<0.05).
Results: Mean bond strength and standard deviations in MPa were: Group 1)10.10±3.84, 2)12.72±6.22, 3)8.75±3.25, 4)13.38±4.24, 5)10.37±3.61, 6)10.20±3.07. In comparison of the bonding agents, SB specimens showed significantly higher bond strength compared to CS3(p<0.05). No statistically significant difference existed between groups 1, 3 and 5(p>0.05) and between 2, 4 and 6(p>0.05). Groups 5 and 6 showed no statistically significant difference which were the control groups(p>0.05). No statistically significant difference existed between groups 1 and 2(p>0.05). Group 4 showed significantly higher bond strength compared to group 3(p<0.01).
Conclusion: Although there were no statistically significant difference between the groups, it can be concluded that application of desensitizer with total-etch bonding system(SB) increased the bond strength.