in vitro evaluation of casein phosphopeptide-amorphous calcium phosphate effect on the shear bond strength of dental adhesives to enamel

background: casein phosphopeptide-amorphous calcium phosphate (cpp-acp) is applied for remineralization of early caries lesions or tooth sensitivity conditions and may affect subsequent resin bonding. this in vitro study investigated the effect of cpp-acp on the shear bond strength of dental adhesives to enamel. materials and methods: sixty extracted human molar teeth were selected and randomly divided into three groups and six subgroups. buccal or lingual surfaces of teeth were prepared to create a fl at enamel surface. adhesives used were tetric n-bond, adhese and adhese one f. in three subgroups, before applying adhesives, enamel surfaces were treated with tooth mousse cpp-acp for one hour, rinsed and stored in 37°c temperature with 100% humidity. this procedure was repeated for 5 days and then adhesives were applied and tetric n-ceram composite was adhered to the enamel. this procedure was also fulfi lled for the other three subgroups without cpp-acp treatment. after 24 hour water storage, samples were tested for shear bond strength test in a universal testing machine. failure modes were determined by stereomicroscope. data were analyzed by t -test and one-way analysis of variance with p < 0.05 as the level of signifi cance. results: in comparison between applied and non-applied cpp-acp subgroups, there was no signifi cant decrease in the shear bond strength to enamel only in tetric n-bond ( p > 0.05). in nonapplied cpp-acp subgroups, there were statistically signifi cant differences among all subgroups. tetric n-bond had the highest and adhese one f had the lowest shear bond strength. conclusion: cpp-acp application reduces the shear bond strength of adhese and adhese one f to enamel but not tetric n-bond. key words: casein phosphopeptide-amorphous calcium phosphate, enamel, etch-and-rinse,self-etch, shear bond strength