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

Abstract

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. bond strength was not influenced by the use of self-etch or one bottle adhesives.