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 (muSBS) 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, muSBS 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 muSBS than the control and CPP-ACP groups after 24 hours (p < 0.05). No significant difference was observed regarding the muSBS of the control and the other groups after 24 h (p > 0.05). No significant difference was observed regarding the muSBS of the PA and PA + CPP-ACP groups (p > 0.05). The muSBS 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.