RESUMO
Purpose: Erosive tooth wear often leads to surface loss requiring restoration of primary teeth with adhesive materials. The purpose of this study was to evaluate the microshear bond strength (µSBS) of different adhesive systems to sound and eroded primary enamel and dentin surfaces. Methods: Half of the samples underwent erosion (immersion in Coca-Cola for one minute five times over five days) and abrasion cycles (brushing with an electric toothbrush, fluoride toothpaste slurry, for one minute at 250 g load). Samples were divided into adhesive groups (n equals 12): Adper Single Bond 2 (etch-and-rinse); Single Bond Universal (self-etch); Optibond FL (etch-and-rinse with fluoride); and Bond-Force (self-etch with fluoride). Resin composite was bonded on sample surfaces and subjected to µSBS test. Data were analyzed by two-way analysis of variance, Tukey test, and chi-square test (P<0.05). The failure mode was determined using a stereomicroscope under 20X magnification. Results: No difference was found between the eroded and sound enamel and dentin (P≥ 0.05) on µSBS test. The failure mode evaluation showed significant differences between sound and eroded dentin (P=0.003) but no difference among the adhesives (P=0.177). Conclusions: Micro-shear bond strength in primary enamel and dentin was not affected by erosion/abrasion or type of adhesive system.