Effect of MTAD and two type of phosphoric acid on bond strength of resin composite to dentin

In this research, MATD and two types of phosphoric acid's effect on bond strength ofthe composite to dentin was evaluated.Methods and materials: 45 premolar healthy teeth mounted in cold acryl were provided. The teeth were sectioned vertically below the enamel and were divided into 3 groups of 15 teeth. Group 1 were etched by Ultradent phosphoric acid for 15 seconds and then washed with pure water and air for 10 seconds. Group 2 were etched by Kimia phosphoric acid for 20 seconds and then washed with pure water and air for 15 seconds. Group 3 were etched by MTAD for 3 minutes and then washed with water for 30 seconds. All of the samples were bonded using single bond (3M-USA); and Z100 composite (3M-USA) were cured on the dentin. All samples were placed in thermo cycle,under 500 cycle period in temperature of 5-55°Cand then placed in incubator apparatus for 24 hours, to reach mouth environment. The samples were examined by tensile bond strength test with Instrone apparatus and the data were analyzed by one way ANOVA and Duncan statistical test. The difference between group 2 and groups 1 and 3 was meaningful but the difference between groups 1 and 3 was not. The bond strength made by Kimia phosphoric acid is less than the one which was made by Ultradent phosphoric acid and MTAD. It seems that because of exciting citric acid which can remove the smear layer and external layer of calcium in dentin, MTAD can make higher bond strength in the same range as Ultradent phosphoric acid, as it can be deeply infiltrated in dentin and can wash easily after use.