Can dentin surfaces be bonded safely with total-etch and self-etch systems?

Abstract

Abstract Objective: To assess and compare the shear bond strengths (SBSs) of orthodontic brackets bonded to enamel and dentin surfaces by using total-etching and 3 different self-etching adhesives. Materials and Methods: A total of 160 extracted mandibular incisors were randomly divided into 4 groups. In Group I, the hard tissue was etched with 37% phosphoric acid; in Group II, Transbond Plus Self Etching Primer (TSEP) system was used; in Group III, Clearfil Tri-S Bond Plus was used; and, in Group IV, AdheSE was used. Each group was divided into 2 subgroups: The enamel surfaces were conditioned in subgroup-A, and the dentin surfaces were conditioned in subgroup-B. The samples were stored in water for 24 h at 37°C and then thermocycled. The SBS in megapascals (MPa) was determined by a shear test with 0.5 mm/min crosshead speed, and failure types were classified with modified adhesive remnant index (ARI) scores. The data were analyzed with two-way analyses of variance, Tukey′s, and Chi-square tests at the 0.05 level. Results: The mean SBS value of subgroup-A in Group I was significantly higher than the mean values in the other groups (P<0.05). There were no significant differences among the SBS values in the other groups (P>0.05). Significant differences were found in the ARI between subgroup-A in Group I and the other groups (P<0.001). Conclusions: When used on the enamel, the self-etch systems did not have bond strengths as high as that in the conventional method. However, the self-etch systems can be used as successfully as the conventional method on dentin surfaces.