Shear bond strength of an orthodontic self-etching adhesive after intracoronary bleaching.

OBJECTIVES: To evaluate the effects of intracoronary bleaching on the bond strength of orthodontic brackets using self-etching and total-etch adhesive systems.

MATERIAL AND METHODS: In 60 bovine incisors, a coronal lingual access was made to clean the pulp chamber and standardise the thickness of the dentine. The sample was randomly divided into four groups (each n = 15): (CT), control group, without bleaching and bonded with the total-etch system (Transbond(™) XT-3M); (CTSE), without bleaching treatment and bonded with the self-etching system (Transbond(™) Plus Self-Etching Primer-3M); (BT), treated with 35% hydrogen peroxide for internal bleaching and bonded with the total-etch adhesive system; and (BTSE), treated with 35% hydrogen peroxide and bonded with the self-etching adhesive system. Shear bond strength was measured using a universal testing machine (EMIC). The adhesive remnant index (ARI) score was verified. The data were analysed using a two-way anova and Tukey test (p < 0.05).

RESULTS: Significant differences were found, and the self-etching adhesive groups presented the highest bond strength values (CTSE=11.55 ± 2.85 MPa; BTSE=14.14 ± 2.23 MPa). The ARI scores revealed significant differences among the groups; the greater amount of remaining adhesive was observed in the CTSE group, and the lowest scores were observed in the BT group.

CONCLUSIONS: The use of the self-etching adhesive system, even after intracoronal bleaching, presented satisfactory adhesive strength for the bonding of brackets.