Effect of different air-drying periods on microtensile bond strength of an adhesive to dentin

Today، use of adhesive systems is the most common materials in restorative dental procedures. The aim of this study was to evaluate the effect of different air-drying periods on the microtensile bond strength of composite to dentin using adhesive. 15 sound molar teeth were selected. The an occlusal surfaces of teeth were removed with silicon carbide disks (3M/USA) to reach flat surface of dentin. Then according to the air drying of solvent، the teeth were divided to five groups. After 5 sec etching and rinsing for 15 sec، the teeth were air dried for 3 sec. Then Singlebond (3M) was used with different air-drying times (0s، 2s، 5s، 10s، 30s) and cured. Then after insertion and curing of Saremco (microhybrid low shrinkage/Switzerland) composite، the teeth were thermocycled for 500 cycles. Then hour glass slabs with 1 mm2 interface was created. Specimens were then subjected to µTBS force until fracture. Data were analyzed using ANOVA and Bonferroni tests. Statistical tests showed that there were significant differences between bond strength of groups (P=0. 002). The mean of µTBS for the 2 Sec and 30 Sec evaporating time was the most and the least vawes، respectively. An optimum air-drying time for solvent evaporation was the lowest time recommended by the manufacturer. Over and under evaporation time decreased µTBS significantly.