80 страниц. 2014 год. LAP Lambert Academic Publishing An in vitro study was undertaken to evaluate the effect of dentin preconditioning with air abrasion on microleakage of class V cavities restored with GIC and Microfilled composite under cyclic loading. 40 mandibular first premolars were taken and divided into four groups. Group I and II were restored with GIC and Group III and IV with microfilled composite. Group I was preconditioned 10% polyacrylic acid Group III with 35% ortho phosphoric acid and group II and IV with air abrasion. Each group was further subdivided in two subgroups, A & B, with each having 5 samples. All subgroup B of each group were subjected to cyclic loading. Loading was done on buccal cusp at an angle of 20 degree to long axis of the tooth. Load of 60 N was applied by the cyclic loading machine at the frequency of 4-6 cycle/sec. After completion of 1, 50,000 cycles (corresponding to six months of clinical usage), sample were analyzed for microleakage. The results were tabulated and evaluated.