Stability of dentin bond strengths using different bonding techniques after 12 months: total-etch, deproteinization and self-etching.

ABSTRACT

This study evaluated the influence of (1) different dentin treatments and (2) storage time on dentin shear bond strengths. Two hundred and twenty-five bovine incisors were collected, ground to expose a flat dentin surface and randomly divided into three groups according to dentin surface treatment (1) Total etch + Single Bond; (2) Total etch + collagen depletion with 10% NaOCl + Single Bond and (3) No etch + experimental self-etching adhesive. Composite was applied to the treated surfaces using a 3 x 5 mm cylindrical Teflon matrix and was light-cured. Each group was further stratified in five subgroups according to storage time in water at 37 degrees C 1 day, 7 days, 30 days, 6 months and 12 months. Shear bond strengths (SBS) were determined and expressed in MPa. Data was analyzed for statistical significance with two-way ANOVA and Tukey's test (p=0.05). No interaction was observed between surface treatment and storage time. Storage time did not significantly affect bond strengths. Statistically significant differences were observed among the different surface treatments. Single Bond applied after total-etch presented higher mean SBS when compared to the other surface treatment methods. Collagen removal negatively influenced SBS, and the experimental self-etching adhesive presented intermediate values.