Effect of Cigarette Smoke on Resin Composite Bond Strength to Enamel and Dentin Using Different Adhesive Systems

Objective: To evaluate the microshear bond strength of composite resin restorations in dental blocks with or without exposure to cigarette smoke. Method: Eighty bovine dental blocks were divided into eight groups (n=10) according to the type of adhesive (Scotchbond Multi-Purpose, 3M ESPE, St Paul, MN, USA [SBMP]; Single Bond 2, 3M ESPE [SB]; Clearfil SE Bond, Kuraray Medical Inc, Okayama, Japan [CSEB]; Single Bond Universal, 3M ESPE [SBU]) and exposure to smoke (no exposure; exposure for five days/20 cigarettes per day). The adhesive systems were applied to the tooth structure, and the blocks received a composite restoration made using a matrix of perforated pasta. Data were statistically analyzed using analysis of variance and Tukey test (alpha<0.05). Results: For enamel, there was no difference between the presence or absence of cigarette smoke (p=0.1397); however, there were differences among the adhesive systems (p<0.001). CSEB showed higher values and did not differ from SBU, but both were statistically different from SB. The SBMP showed intermediate values, while SB demonstrated lower values. For dentin, specimens subjected to cigarette smoke presented bond strength values that were lower when compared with those not exposed to smoke (p<0.001). For the groups without exposure to cigarette smoke, CSEB showed higher values, differing from SBMP. SB and SBU showed intermediary values. For the groups with exposure to cigarette smoke, SBU showed values that were higher and statistically different from SB and CSEB, which presented lower values of bond strength. SBMP demonstrated an intermediate value of bond strength. Conclusion: The exposure of dentin to cigarette smoke influenced the bonding strength of adhesives, but no differences were noted in enamel.