Microtensile bond strengths of seven dentin adhesive systems

Objectives. The purpose of this study was to evaluate the microtensile bond strengths of seven dentin adhesive systems (Solid Bond, EBS-Multi, PermaQuik, One Coat Bond, Gluma One Bond, Prime & Bond NT/NRC and Clearfil Liner Bond 2V) and their respective fracture modes. Methods. Superficial occlusal dentin of extracted human molars was exposed, finished with wet 600-grit silicon carbide paper, and a block of resin composite bonded with the above adhesives according to the manufacturersʹ instructions. The teeth were kept in tap water for 24 h at 37°C, sectioned to obtain three or four bar-shaped specimens, which were then shaped to an hour-glass form of 1.2±0.02 mm diameter. The specimens were stressed at a crosshead speed of 1 mm/min until rupture of the bond. The mean bond strengths were compared using one-way ANOVA and LSD tests. The frequency of fracture modes was compared using Kruskal–Wallis and Mann–Whitney U-tests. Results. Mean microtensile bond strengths ranged from (17.8±7.0) MPa for Solid Bond to (36.0±8.1) MPa for Clearfil Liner Bond 2V. The bond strength of Clearfil Liner Bond 2V and PermaQuik (30.8±8.5 MPa) were not significantly different, and were higher than all other materials. Bond strengths of Solid Bond (17.8±7.0) MPa, EBS-Multi (18.7±5.0) MPa, One Coat Bond (21.9±5.6) MPa, and Gluma One Bond (23.4±5.2) MPa were not significantly different. SEM examination indicated that Solid Bond, EBS-Multi and One Coat Bond showed no significant difference in failure modes but were significantly different from PermaQuik, Prime & Bond NT/NRC and Clearfil Liner Bond 2V. Significance. The self-etching primer system, Clearfil Liner Bond 2V, provided the simplest bonding technique, and together with PermaQuik exhibited greatest bond strength to dentin.