Tensile bond strengths of fourth- and fifth-generation dentin adhesives with packable resin composites.

PURPOSE: Placement of packable composites would be simplified if a single-bottle dentin bonding agent, rather than the more complex, multiple-bottle dentin bonding agents, involving multiple steps, could be used successfully with adequate bond strength. This study was designed to compare the tensile bond strengths to extracted human dentin of four single-bottle (fifth-generation) and four multiple-bottle (fourth-generation) dentin bonding agents with four packable composites. MATERIALS AND METHODS: Packable composites (P60, 3M Dental Products Division; ALERT, Jeneric-Pentron; Pyramid Dentin, Bisco; and Clearfil AP-X, Kuraray America) were tested for in vitro tensile bond strength to human dentin with their single-bottle and their multiple-bottle dentin bonding agents. Bond strengths were measured using a truncated cone tensile test, with a bonding diameter of 3 mm, after storage of specimens in water at 37 degrees C and 100% relative humidity for 24 hours, and using a testing machine at a crosshead speed of 0.5 mm per minute. RESULTS: Means and standard deviations (n = 10) of tensile bond strengths (MPa) for the single-bottle system were P60, 21.3 MPa (6.7); ALERT, 26.6 MPa (4.2); Pyramid Dentin, 14.8 MPa (4.4); and Clearfil AP-X, 18.6 MPa (3.7). For the multiple-bottle system they were P60, 20.0 MPa (8.6); ALERT, 20.6 MPa (6.2); Pyramid Dentin, 16.0 MPa (3.4); and Clearfil AP-X, 17.8 MPa (6.0). Two-way analysis of variance showed significant differences among composites but no significant differences between single-bottle and multiple-bottle bonding agents. The Tukey-Kramer interval (p < .05) for comparisons of bond strengths among composites was 4.8 MPa. CONCLUSIONS: For single-bottle agents, bond strengths were ranked as ALERT > P60, P60 = Clearfil, P60 > Pyramid, and Clearfil = Pyramid. For multiple-bottle agents, there were no significant differences in bond strengths among the composites. CLINICAL SIGNIFICANCE: Single-bottle bonding agents provide similar in vitro bond strengths for use with packable composites as do the same manufacturers' multiple-bottle bonding agents.