A 24-month randomized clinical trial of a two- and three-step etch-and-rinse technique.

Purpose: This 24-month randomized paired tooth clinical study evaluated the performance of All Bond 3 used in the simplified (2-step) and full (3-step) versions.

Methods: 33 patients, with at least two similar sized non-carious cervical lesions participated in this study. A total of 66 restorations were placed, half using the 2-step All Bond 3 (AB3-2) and the other half using 3-step All Bond 3 (AB3-3). The restorations were placed incrementally using the composite resin Aelite. The restorations were evaluated at baseline and after 6, 12 and 24 months following the modified USPHS criteria. Statistical differences between the adhesive were tested using with McNemar's test and clinical performance over time for each material with the Fisher's exact test (alpha = 0.05).

Results: After 24 months, six AB3-2 and four AB3-3 were rated as bravo for marginal discoloration but did not differ from each other significantly (P > 0.05). The retention rates at 24 months of AB3-2 and AB3-3 were 90.9% and 97.0%, respectively (P > 0.05).