Effect of Composite Elasticity and Filler Concentration on Shear Bond Strength of Composite to Dentin

Statement of problem: resin composites are one of the most popular toothcolored restorative materials. their enamel and dentin bonding ability are basedon many factors, including elasticity and filler concentration.purpose: this study was undertaken to evaluate the effect of volumetric fillerpercentage and modulus of elasticity of six composites by measuring shear bondstrength to dentin of the bovine teeth as experimental bonding substrate.materials and methods: eighty bovine incisors were prepared and divided intoeight groups. tetric ceram, tetric flow, compo glass f, helimolar ro, definite,and degufill mineral were applied respectively. a fifth generation of dentinbonding system [single bond (3m, usa)] was used for all the groups. thevolumetric filler percentage of each composite was obtained from theirspecification data. the modulus of elasticity was determined, using the formulapresented by bream et al. (1986). then, in last two groups heliomolar ro anddefinite were bonded using their own bonding systems, syntac multicomponent,and definite multibond. the shear bond strength was measured according to theiso/tr 11405. pearson’s correlation test was used to compare the result withgroups 4 and 5.results: the results indicated that the relationship between both the fillerpercentage and the modulus of elasticity with the shear strength was 16%(p<0.005). there was a significant difference between groups 4 and 7, but nosignificant difference was observed between groups 5 and 8.conclusion: using composites with a higher filler content and modulus ofelasticity resulted in higher shear bond strength in dentin bonding system. ourresults showed that the corresponding dentin bonding system of composites hadbetter results.