Influence of pretreatments on microtensile bond strength to eroded dentin using a universal adhesive in self-etch mode

Abstract

To evaluate the influence of pretreatments on microtensile bond strength (μTBS) to eroded dentin when using a universal adhesive in self-etch mode. Forty-eight human molars were randomly assigned to six groups (G1–G6, n = 8) and ground down until dentin exposure. G2–G6 were eroded with citric acid (pH 2.6) for 10 × 2 min (within 12 h) on 5 consecutive days. G1 and G2 served as uneroded and eroded controls and were not pretreated. G3 and G4 were pretreated for 60 s with NaOCl (10% and 5%, respectively). G5 was airborne-particle abraded using Al 2 O 3 for 15 s, and G6 was roughened with a diamond bur. The universal adhesive Scotchbond Universal was applied in self-etch mode. After composite build-up, μTBS was determined. Control group G1 (uneroded) showed higher μTBS than G2 (eroded). The μTBS (mean MPa ±SD) of G5 (airborne-particle abrasion; 11.6 ± 4.6) and G6 (bur-roughening; 11.0 ± 3.3) did not differ significantly from the μTBS of G1 (12.4 ± 4.2). Significantly higher μTBS compared to all other groups was observed in G3 (NaOCl 10%; 17.6 ± 7.6). Pretreatment with NaOCl 5% (G4) achieved significantly lower μTBS (3.5 ± 2.6) than the other groups, except for G2 (8.8 ± 2.0). Pretreatment with 10% NaOCl, diamond bur roughening or airborne-particle abrasion can increase bond strength of the tested adhesive to eroded dentine. Pre-treatment with 5% NaOCl is not recommended.