EFFECT OF ENAMEL AND DENTIN SURFACE WETNESS ON SHEAR BOND STRENGTH OFCOMPOSITES

Purpose. This study investigated the effect of the wetness of human en amel and dentin surfaces on the sheer bond strength of composites. Mat erial and methods. Seven dentin bonding systems were used. Three metho ds of preparing the enamel or dentin surface before applying primer or bonding agent were adopted as test conditions: wet (blot dried), semi dry (3-second air blast), and dry (15-second air drying). Shear bond s trength was measured with a universal testing machine. Mean bond stren gths mere analyzed with analysis of variance and Scheffe's F-test. Ena mel and dentin surfaces were observed by a dissecting microscope after shear bond testing. Results. Enamel specimens tested by all systems a nd dentin tested by two systems did not reveal significant differences in shear bond strengths (p > 0.05). Among dentin specimens tested by two systems with water-based primers, the shear bond strength values o f the dry technique group were higher than those of the other two grou ps (p < 0.05). However, among dentin specimens tested by systems havin g acetone-based primers or bonding agents, bond strength values of the wet or semidry technique groups were higher than those of the dry tec hnique group (p < 0.05). Conclusion. It was concluded that some water might be needed by dentin surfaces or for primers to obtain high bond strength on the dentin surface, but that drying methods did not affect bonding strength to enamel surfaces either before priming or after co nditioning.