Influence of different test parameters on the microshear bond strength of two simplified etch-and-rinse adhesives.

PURPOSE: To evaluate the effect of different test parameters on the resin-dentin microshear bond strength (μSBS). MATERIALS AND METHODS: A 1.5-mm-thick dentin disk was prepared in each of 140 human molars. The disks were divided into five groups to test the following variables: time of adhesive light polymerization (n = 20), storage time (n = 40), bonding area (n = 40), Tygon tube removal (n = 20), and time of composite placement (n = 20). The adhesives were applied and each specimen was subjected to μSBS testing. All fractured specimens were observed with SEM. The data from each experiment were subjected to two-way ANOVA and Tukey's test (α = 0.05). RESULTS: The storage time, bonding area, and Tygon tube removal did not influence the μSBS. Higher μSBS values were found when empty Tygon tubes were filled after positioning and when the adhesive was light polymerized before Tygon tube placement (p < 0.05). CONCLUSIONS: Differences in test parameters affected the μSBS of adhesives, especially the time of adhesive light polymerization and composite placement.