[Comparison of solvent evaporation in the self etch and total etch adhesives in different air draying times]

Different adhesives with different solvents may have different solvent evaporation rates. The purpose of this study was to evaluate the solvent evaporation in the self etch and total etch adhesive in different air drying times. Five adhesives were used in this study: Excite, Prime and Bond NT, UNO, Single Bond, SE Bond Primer. Twelve drops of each adhesive were used for each period of air drying [5, 15, 30 sec]. The percentage of mass loss was measured during each test. Data were analized using two-way ANOVA and Tukey. Acetone base adhesives showed more loss of mass than other adhesives [P<0.01]. P and B NT showed more loss of mass than other adhesives in all air drying times [P<0.01]. Adhesives showed different evaporation rates in different air times [P<0.01]. Adhesives with acetone/ water or alcohol/water solvent shows more stable behavior in comparison with adhesives containing pure aqueous solvents

[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 occlusal surfaces of teeth were removed with silicon carbide disks [3M/USA] to reach the 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 mm[2] interface was created. Specimens were then subjected to microTBS 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 microTBS 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 microTBS significantly.