The Effect of Simulated Human Salivary Enzymes and Matrix Metalloproteinase (MMP) Inhibition on the Degradation and Fracture Toughness of the Self-etched Resin-dentin Interface

Background: Oral esterase activities and dentinal matrix metalloproteinases (MMPs) contribute to interfacial degradation of composite restorations, compromising structural integrity, and increasing risk of secondary caries. Hypothesis: MMP inhibition modulates simulated human salivary esterase (SHSE) accelerated degradation of mechanical performance parameters for composite-dentin bonds achieved via self-etched adhesives. Objective: Assess the effect of SHSE and MMP inhibition on biostability, interfacial fracture toughness (FT), and failure mode (FM) for self-etched resin-dentin interfaces. Materials and Methods: FT and FM analyses were performed on mini short-rod FT specimens (N=10/group), prepared with Easy Bond, with and without MMP inhibition (galardin), after incubation for 0, 7, 30, 90, or 180 days in phosphate buffered saline (PBS) or SHSE. Results and Conclusions: FM shifts into the composite/adhesive vs. hybrid-layer after longer incubation periods. Despite higher amounts of the degradation marker, Bis-hydroxy-propoxy-phenyl-propane, collected from SHSE vs. PBS (pM.A.S