Shear bond strengths of two commercially available dentine-amalgam bonding systems

The purpose of this in vitro study was to determine the shear bond strengths (SBS) of amalgam to dentine treated with the Amalgambond Plus System (AM) and All-bond 2 System (AL) after storage periods in physiological saline for up to 48 weeks.

The occlusal superficial dentine surfaces of 150 extracted human molars were exposed by wet grinding on 600-grit silicon carbide and the bonding area demarcated with a perforated adhesive tape. Freshly mixed Tytin amalgam was transferred to the opening in a split Teflon mold on the demarcated dentine surfaces treated with either AM or AL as directed by the manufacturers. The SBS of AM after 24 h (A), 4 weeks (B), 12 weeks (C), 24 weeks (D), and 48 weeks (E), and of AL after 24 h (F), 4 weeks (G), 12 weeks (H), 24 weeks (I), and 48 weeks (J), were determined with a knife-edged rod at a crosshead speed of 0.5 mm/min and expressed in megapascal (MPa). The data were analyzed by ANOVA and Student's t-test.

The mean +/- SD of SBS in MPa were: A: 14.6 +/- 4.0; B: 14.5 +/- 3.6; C: 15.3 +/- 4.8; D: 14.6 +/- 4.6; E: 13.9 +/- 4.0; F: 9.5 +/- 4.7; G: 12.1 +/- 1.7; H: 10.2 +/- 3.5; I: 12.0 +/- 3.9; J: 11.9 +/- 3.5. The SBS of the five groups treated with AM (A, B, C, D and E) were not significantly different (P > 0.05) and the SBS of the five groups treated with AL (F, G, H, I and J) were not significantly different (P > 0.05). The SBS of A vs. F, B vs. G, ad C vs. H, were significantly different (P < 0.05), but D vs. I and E vs. J were not significantly different (P > 0.05).

The SBS of amalgam to dentine treated with AM and AL were not adversely affected by the duration of storage.