Microtensile bond strengths to enamel of self-etching and one bottle adhesive systems.

UNLABELLED: This study compared the enamel bond strengths of self-etching and one bottle adhesives, and evaluated microscopically their debonding modes. Evaluated systems were: Self-etch--Prompt L-Pop (LP); one bottle, total etch--Single Bond (SB), Prime & Bond NT (PB); compomer--Hytac Aplitip (HA), F2000 (F2); resin composite- Reference 21 Aplitip (R2), Herculite XRV (XRV), Esthet.X (EX); in the following combinations: LP/HA; LP/R2; SB/F2; SB/XRV; PB/EX. Flat surfaces of enamel were ground on caries free extracted third molars. An adhesive resin was applied to this surface and a restorative material built on it. The teeth were sectioned longitudinally into 1 mm thick specimens and trimmed to a 1 mm2 area at the enamel/adhesive interface. For each material combination, 10 specimens were tested. Microtensile bond strengths were determined at 0.5 mm min(-1). Fractured specimens were examined using confocal and scanning electron microscopy to determine failure modes. Bond strength data was analysed using Kaplan-Meier survival analysis, a log-rank test and a Bonferroni multiple comparison. Failure mode data was analysed with a chi2 test. The interface of additional fluorescent-labelled specimens was examined by laser scanning confocal microscopy. The bond strength data showed significant differences: LP/R2 > LP/HA, SB/F2 and PB/EX; SB/F2 < LP/HA, SB/XRV and PB/EX. Both compomers principally exhibited cohesive failure. Resin composite materials showed more complex failure modes. Fluorescence images demonstrated interfacial characteristics consistent with the failure modes observed. SIGNIFICANCE: bond strength was not influenced by the use of self-etch or one bottle adhesives.