Micro-Shear Bond Strength of Indirect Composite Resin to Three Different Computer-Milled Cores After Thermocycling

Background and aim: the aim of this study was to evaluate the micro-shear bond strength of an indirect composite resin to three different types of cores. materials and methods: in this in-vitro study, 14 blocks (5×5×2 mm) were designed and milled by computer from cobalt-chromium (co-cr) alloy, zirconia, and polyether ether ketone (peek). each sample was treated according to the manufacturer’s instructions, and the appropriate primer, and a layer of crea.lign opaquer were applied on the surface. for micro-shear bond strength test, a plastic tube with an internal diameter of 1 mm and height of 2 mm was placed on each block, and crea.lign paste was condensed in it. the crea.lign paste and opaquer were light-cured separately for 180 s, and finally for 360 s. all samples were placed in 37°c distilled water for 24 h and thermocycled for 5000 cycles (5 to 55°c). the microtensile tester machine was used to measure the micro-shear bond strength. the samples were also evaluated for failure modes. data were analyzed using one-way anova (p<0.05). results: according to one-way anova, the mean micro-shear bond strength (mpa) in co-cr alloy, zirconia, and peek groups was 26.09±5.23, 23.49±5.48, and 20.58±5.68 mpa, respectively. there was no significant difference in micro-shear bond strength of the three groups (p= 0.099). the most frequent mode of failure in all three groups was adhesive, followed by mixed, and cohesive. conclusion: applying the standard procedure, type of core material had no significant effect on the micro-shear bond strength of crea.lign composite veneer.