Microtensile bond strengths of one-bottle dentin adhesives

Purpose: To investigate the in vitro performance of three one-bottle adhesives by measuring their dentin microtensile strength. Materials and Methods: Extracted human molars had the dentin exposed on the occlusal surface. The teeth were randomly assigned to three dentin adhesives: Group 1 - Prime & Bond 2.1; Group 2 - Prime & Bond NT; and Group 3 - Experimental (unfilled NT). All materials were applied as recommended by the manufacturer. A high-density resin composite (Surefil) was packed on the bonding area in five increments. Specimens (sticks) were obtained using a diamond disc and were stored in distilled water for 24 hrs. The microtensile bond strengths were measured with a universal testing machine. Results: Group 1: 54.3 +/- 15.6 MPa; Group 2: 62.0 +/- 17.6 MPa; Group 3: 54.6 +/- 16.8 MPa. Although no statistically significant difference was found between pairs of means, Prime&Bond NT showed a tendency for higher bond strengths.