The Inhibitory Effects Of Quaternary Ammonium Methacrylates On Dentin Matrix Metalloproteinases

Objectives:The results of extensive researches demonstrated that the degradation of exposed collagenfibrils in hybrid layer has associated with the activation of collagen-bound MMPs and/ornon-collagen-bound MMPs. Ongoing research is currently being conducted on identifyingquaternary ammonium methacrylate monomers with anti-MMP properties, improving thedurability of dentin bonding strength. The objective of this study was to examine thepotential of DMAE-CB, MAE-DB and MAE-HB as MMPs inhibitors and determine theeffective anti-MMP group of QAMs; incorporated the three monomers into AdperTMSingle Bond2and evaluated the possible resistant effect of QAMs on enzymaticdegradation of resin-dentine interfaces, exploring a new way to improve the dentin bonding durability.Methods:1The assay employed purifed recombinant human MMP-9and the Sensolyte GenericMMP colorimetric assay kit for screening the anti-MMP activity of DMAE-CB, MAE-DBand MAE-HB that was synthesized with further purifcation. In this study, we made use ofthe structure differences between MMA, METMAC and DMAE-CB to determine theeffective group for the anti-MMP efficiency, via comparing the inhibitory percentages ofthe three monomers on soluble MMP-9.2In this research, ultimate tensile strength, precision weighing and morphology of dentincollagen were employed to evaluate the inhibitory effects of DMAE-CB, MAE-DB andMAE-HB on collagen-bound MMPs in demineralized dentin beams.3Micro-tensile bond strength, failure modes and nanoleakage were examined to evaluatethe resistent effects of QAMs-incorporated dental adhesive on enzymatic degradation ofresin-dentine interfaces.Results:1All the three monomers had effective anti-MMP property. The enzymes wereincreasingly inhibited when they were incubated with increasingly higher concentrationsof QAMs. The inhibitory effects of30%METMAC and30%DMAE-CB were95.6±1.7%and94.3±2.3%, whereas30%MMA inhibited rhMMP-9by only17.7±3.1%(P <0.05).It can be concluded that cationic quaternary ammonium group might be the effectiveanti-MMP group of QAMs.2All the three monomers had effective effects on the endogenous bound MMP activity ofdemineralized dentin matrices and could protect the collagen fibrils from degradation.3After the enzymatic hydrolysis of different time, the decline of QAMs incorporatedadhesives on micro-tensile bond strength was much less, failures occurred through the topof the hybrid layer and the statistical analysis of the number of sections assigned to thedifferent scores revealed that the silver nitrate uptake of the negative control group were significantly different from QAMs incorporated adhesives (P <0.05). Dental adhesivesincorporated with QAMs could improve the anti-degradation ability of resin-dentininterfaces after polymerization.