The effect of proanthocyanidin and casein phosphopeptide‐amorphous calcium phosphate on the bond strength durability to caries‐affected dentin

OBJECTIVES: The aim of this study was to evaluate the effect of proanthocyanidin (PA) and casein phosphopeptide‐amorphous calcium phosphate (CPP‐ACP) paste on the micro‐shear bond strength (μSBS) durability of an etch‐and‐rinse adhesive to caries‐affected dentin (CAD). MATERIALS AND METHODS: The occlusal surfaces of 80 human molars with occlusal caries were ground to expose flat dentin surfaces with CAD. Then, they were randomly divided into four groups (n = 20) according to the CAD pretreatment. The study groups included no pretreatment, pretreatment with CPP‐ACP for 3 min, pretreatment with PA for 1 min, and pretreatment with PA for 1 min followed by CPP‐ACP for 3 min before adhesive application. After restoring the specimens with composite resin, μSBS testing was performed for half of the bonded surfaces in each group after 24 h and the other half was tested after 6 months of water storage and failure mode analysis was performed. RESULTS: The PA group was associated with a higher μSBS than the control and CPP‐ACP groups after 24 hours (p < 0.05). No significant difference was observed regarding the μSBS of the control and the other groups after 24 h (p > 0.05). No significant difference was observed regarding the μSBS of the PA and PA + CPP‐ACP groups (p > 0.05). The μSBS of the 6‐month specimens was significantly lower than those of the 24‐h specimens for all the groups (p < 0.05) except for the PA group which did not exhibit a significant difference between the two times (p > 0.05). The most common type of failure was mixed failure. CONCLUSION: PA pretreatment could stabilize the CAD‐resin interface and protect degradation over time. The same effect was not observed for CPP‐ACP or PA + CPP‐ACP.