Bonding Performance and Interfacial Assessment of Experimental S-PRG Containing Adhesive

Objectives: To evaluate the microtensile bond strength (µTBS) before and after dynamic chemical formation of secondary caries of S-PRG containing dental adhesives with different concentrations
Methods: Occlusal surfaces of human teeth (n=20) were ground to obtain flat surfaces and randomly assigned to four groups according to S-PRG concentration: 0% (control), 13% (low),27% (moderate) and 40% (high) S-PRG containing adhesives (Shofu, Kyoto, Japan). The restored teeth then sectioned into 1-mm² beams after 24h and were divided randomly into 3 subgroups: Immediate, secondary caries formation (4h Demineralization followed by 20h SBF remineralization for 7-days) and Simulated body fluid (SBF) storage for 1w. µTBS was measured at a crosshead speed of 1 mm/min. SEM analysis was performed after debonding and Fluorescent microscope was used to evaluate the nanoleakage and mineral deposition at dentin-resin interface. Weibull analysis was performed for µTBS data
Results: The µTBS for 0% S-PRG was the highest followed by 13% S-PRG, 27% S-PRG, and 40% S-PRG after immediate, dynamic chemical formation of secondary caries cycles and 1w SBF storage. The µTBS decreased significantly only in 0% S-PRG after dynamic chemical formation of secondary caries cycles and 1w SBF storage, compared to all S-PRG containing adhesives which showed insignificant difference after both dynamic chemical formation of secondary caries cycles and 1w SBF storage
Conclusions: S-PRG containing adhesives showed high bond strength stability after dynamic chemical formation of secondary caries with preferable low and moderate S-PRG concentrations