Effect of application time of one-step-etch adhesive (all-in-one) on composite resin-bovine enamel shear

Abstract

Despite self-etch adhesives have resulted in acceptable Bond strength to dentin, some concerns remain regarding both the short and long-term bonding effectiveness to enamel, in particular when so-called mild self-etch adhesives. The purpose of this study to determine the effect of application time four new all-in-one adhesives on shear bond strength composite resin to ground bovine enamel were given. Methods and Materials: In this study, bovine incisores used in 8 different groups. Sample size for each group of 22 teeth and a total 176 teeth were used. after removing the roots using a low-speed saw with a diamond-impregnated disk, The labial surfaces were ground on wet 240-grit and 600-grit SiC paper to a flat enamel surface. Groups 1 to 4, four types all-in-one adhesive were applied per the manufacturers directions. in group 5 to 8 the conditioning time wase twice as long as that recommended by the manufacturer. In the next step, the same type of composite were placed plastic mold 3mm size diameter and height. Bonded specimens were stored in water at 37 C for 24 hours, and subsequently came under the act of samples with thermocycl conditions and 500 cycles in the range 552 to 52 C with 15 seconds were interval time. shear bond strength Were determined using a knife edge Chisel Hounsfield Test equipment at a crosshead speed of 1 mm/minute. data collected by analysis of variance tests were two way analysis. Then prosecute Duncan test for comparison between independent groups and T was used for comparison within groups. Results: The highest mean bond strengths were obtained with Opti Bond all-in-one regardless of the application time and the least to the seventh group. G-Bond(P=0.002) and Clearfil S3 Bond(P=0.04) were the only adhesives for which double application time resulted in statistically higher enamel bond strengths than the recommended application time and not found significant difference for two groups Absolute 2 (P=0.26) and Opti Bond all-in-one (P=0.39). Conclusion: A: double Application time of the all-in-one adhesives with high pH can be as a effective way to increase of resin composite/enamel bond strength. B:double application time increased Bond strength for G-Bond and Clearfil S3 bond to enamel.