Bond strengths of eight contemporary adhesives to enamel and to dentine: an in vitro study on bovine primary teeth

Abstract

The aim of this study was to compare the shear and tensile bond strengths of eight adhesive systems to the enamel and dentine of primary bovine teeth. Two hundred and fifty-six noncarious bovine mandibular primary incisors were collected and stored in an aqueous 1% chloramine solution at room temperature for no longer than 3 months after extraction. The tested adhesives were: Clearfil SE bond (SE); Adper Prompt L Pop (LP); Optibond Solo Plus Self-etch (OB); AdheSE (AS); Xeno III (XE); Scotch Bond 1 (SB); Etch & Prime 3.0 (EP); and I Bond (IB). For the shear bonding test and the tensile bonding test, the labial surfaces of primary incisors were used. To obtain a flat surface, the labial surfaces of the teeth were sanded on wet silicon carbide paper, first with number 200 grit for 20 s and then with number 600 grit for 60 s (n = 128; 64 for shear bonding and 64 for tensile bonding). The results were compared with an analysis of variance and Bonferroni's multiple comparison test. Shear bond strength values ranged from 18.1 to 8.9 MPa on enamel (in decreasing order, SE, LP, OB, AS, XE, SB, EP and IB), and from 17.8 to 8.2 MPa on dentine (in decreasing order, SE, SB, OB, AS, XE, LP, IB and EP). Tensile bond strength values ranged from 13.1 to 6.7 MPa on enamel (in decreasing order, SE, OB, AS, LP, XE, IB, SB and EP), and from 12.1 to 5.7 MPa on dentine (in deceasing order, SE, SB, OB, AS, XE, LP, IB and EP). The differences in bond strengths between the eight systems on enamel and dentine were all statistically significant. This was true for both the shear and tensile bond strengths. The highest shear bond strength was achieved by SE on enamel and dentine, and the lowest by IB on enamel and EP on dentine. The highest tensile bond strength was obtained by SE on enamel and dentine, and the lowest by EP. Shear bond strengths were significantly higher on enamel when compared to dentine for five of the eight adhesives systems, and tensile bond strengths were significantly higher on enamel when compared to dentine for all but two systems.