Bond strength evaluation of self-etch and total-etch adhesive systems on intact and ground human enamel

The aim of this study was to evaluate the bond strength of adhesive systems to intact and ground enamel. Enamel blocks from buccal and lingual surfaces of third molars were used for bonding procedures. Intact or ground (600-grit SiC paper) enamel surfaces were bonded using two "etch&rinse" adhesives (Prime&Bond 2.1 and Single Bond), three self-etching primer systems (Optibond Solo Plus SE; Tyrian SPE/One-Step Plus and UniFil Bond) or two self-etching adhesives (One-Up Bond F and Xeno III). A 6-mm composite crown was built on the bonded surfaces and samples were stored for 24 hs at 37°C. Samples were sectioned into 0.9-mm-thick slabs, each slab trimmed to a cross-sectional area of 0.8 mm² and specimens loaded to failure at a crosshead speed of 0.5 mm/min, using a universal testing machine. Microtensile bond strength data (n=6) were analyzed using Kruskal- Wallis and Dunn tests. Differences in bond strength between intact and ground surfaces were not significant for both "etch&rinse" adhesives, Tyrian SPE/One-Step Plus, UniFil Bond and Xeno III systems. The enamel surface preparation resulted in higher bond strength for Optibond Solo Plus SE and One-Up Bond F systems. Enamel preparation using 600-grit SiC paper is unlikely to affect resin-enamel bond strengths.