The purpose of this in-vitro study was to investigate the shear peel bond strength (SPBS), incidence of immediate bond failure, enamel fracture and adhesive remnant index (ARI) for two different self-etching primer systems3,4compared to both a directly bonded separate etch and prime control as well as an indirectly bonded separate etch and prime control1,2.
One hundred ninety-two human bicuspid teeth were arranged to duplicate human archforms, with four arches of twelve teeth per group. The teeth were etched, bonded and stored for 100 days at 37°C, thermocycled and subsequently debonded with an Instron universal testing machine.
All adhesive groups demonstrated sufficient mean in-vitro bond strength values of 13.3 MPa1, 11.2 MPa3, 10.5 MPa21and 10.0 MPa4. ANOVA showed a statistically significant difference (p\u3c0.05) among the four adhesive groups. The Tukey-Kramer test found that the directly bonded separate etch and primer group had a significantly higher
bond strength compared to the other three groups. Three bond failures were noted upon transfer tray removal, all in the indirectly bonded Reliance self-etching primer group. ARI scores revealed that for two thirds of all the teeth some amount of composite remained on the tooth. The highest incidence of enamel fracture occurred in the directly bonded separate etch and prime group
