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

Background: Oral esterases and dentinal matrix metalloproteinases (MMPs) contribute to interfacial degradation of composite restorations, compromising structural integrity, and longevity. Hypothesis: MMP inhibition modulates simulated human salivary esterase (SHSE) degradation of mechanical performance parameters for composite-dentin bonds with total-etched adhesives. Objective: Assess effect of SHSE and MMP inhibition on biostability, interfacial fracture toughness (FT), and failure mode (FM) for total-etched resin-dentin interfaces. Methods: FT and FM analyses were performed on mini short-rod FT specimens (N=10/group), prepared with Scotchbond MP, with/without MMP inhibition (galardin), after incubation for up to 180 days in phosphate buffered saline (PBS) or SHSE. Results: The amount of a resin degradation biomarker, Bis-hydroxypropoxyphenylpropane (BisHPPP), was higher for SHSE vs. PBS incubated specimens. FT after 180-days in SHSE, with/without galardin, were significantly lower (0.71±0.2 MPa√m) than non-inhibited 0-day specimens (1.06±0.4 MPa√m). Galardin slowed down the trend of change in fracture mode from composite/adhesive into hybrid layer over time.M.Sc