Acrylamide As A Novel Monomer For Dentin Adhesion Based On Mussel's Biological Adhesion

Objectives The problem of poor bonding durability exists in modern minimally invasive dental defect repair based on composite resin bonding.This study aimed to investigate the effects of the biomimetic monomer N-2-(3,4-dihydroxylphenyl)acrylamide(DAA)on collagen fibers degradation,collagenase activity,and change in the microtensile bond strength of resin-dentin bonding surface after thermocycling in order to improve the durability of dentin bonding.Methods DAA synthesis:Synthesis according to design requirements.The synthesized product was detected and analyzed by 1hydrogen-nuclear magnetic resonance(~1H-NMR)and High resolution mass spectrometer(HRMS).Explore the factors that affect the ability of DAA to inhibit the degradation of collagen fibers and optimize the use of DAA:collagen membranes co-cultured with DAA solution(with a series of concentration,a state of unoxidation or oxidation,oxidized DAA during reaction with collagen or before the experiment and series of time)and degradation was evaluated by measuring the released hydroxyproline(HYP)through a micro hydroxyproline content assay kit.Explore the inhibition of collagenase activity by DAA:The optimized DAA in the above experiments was co-cultured with clostridiopeptipase-A solution in an acidic(p H=5)and alkaline(p H=8)environment,respectively.Collagenase activity in each group was determined by colorimetry using Biovision collagenase activity detection kit.Evaluate the ability of DAA to inhibit collagenase activity in acidic and alkaline environments.Explore the effect of DAA on the adhesive strength of dentin:Forty human third molars were divided into two groups,and an etch-and-rinse adhesive system was applied to both groups.In the experimental group,the adhesive interface of the third molars was treated with DAA solution optimized operating conditions in the above experiments.In the control group,the third molars were treated with deionized water.The microtensile test(?TBS)was performed before and after thermocycling,and the adhesive interface was evaluated through SEM.At the same time,the same adhesion model was constructed,and the dentin was dissolved by silver nitrate staining and hypochlorous acid,respectively.Nanoleakage and adhesion interface morphology were observed by scanning electron microscope(SEM).Evaluate the effect of DAA on the durability of dentin bonding.Results Oxidized DAA inhibited the enzymatic hydrolysis of the collagen membrane in a concentration-dependent manner,whereas unoxidized DAA don't induced inhibitory effects on collagen degradation.The interaction of DAA with collagen was not time dependent.The oxidation of DAA did not interfere with the interaction of oxidized DAA with collagen.Oxidized DAA could inhibit the collagenase activity in acidic and alkaline environments.Although no significant difference was observed in the immediate?TBS(MPa)between the experimental group and the control group,?TBS after thermocycling was significantly greater in the DAA-treated groups than in the control group.SEM observed that after thermocycling,adhesion interface nanoleakage increased significantly in the control group,while no significant change was observed in the experimental group.At the same time,SEM showed that the resin convex and hybrid layer formed in the adhesive surface of the experimental group before and after thermocycling treatment were still preserved under hypochlorite corrosion,while the resin convex and flat in the control group had a smooth surface(the hybrid layer was lost).Conclusion Oxidized DAA can protect resin-dentin bonding interface and increase the durability of dentin bonding.It has the potential to be used in clinical dentin bonding as a new type of dentin bonding monomer.