Effect Of DMSO Wet Adhesion On Immediate And Aging Bond Strength Of Resin-Dentin In Self-etching System

Objective:In this experiment,DMSO wet bonding technology was applied to self-etching system to investigate the change of bonding strength of resin-dentin bonding immediately and after aging,and two kinds of commonly used self-etching bonding agents were compared.The mixed layer between resin and dentin was evaluated by micro-tensile bonding strength test and scanning electron microscopy analysis,and the effect of DMSO(dimethyl sulfoxide,(CH3)2SO)wet bonding technology on dentin bonding was explored.To improve dentin bonding strength in clinic provides new ideas and theoretical guidance for dentists to choose bonding agents.Methods:Forty-eight intact and caries-free third molars were extracted from 18-24 years old patients.After disinfection and cleaning,the crown enamel was cut horizontally in the middle of the crown and removed.The enamel around the crown was removed parallel to the long axis of the tooth.The extracted teeth were randomly divided into four groups(n= 12):(A)Adhesive A(Adeper Easy One);(B)DMSO pretreatment combined with adhesive A;(C)Adhesive B(Single Bond Universal);(D)DMSO pretreatment combined with adhesive B,each group was further divided into 1 and 2 groups.The crown resin thickness of each teeth in vitro is 5 mm.The teeth in vitro are cut along the buccal-lingual direction and near-far-median direction with a high precision and low-speed cutting machine.Finally,the specimens with cross-sectional area of 0.9 x 0.9 mm 2 and 8 mm long are cut into micro-tensile bonding specimens.The 1 group of specimens were stored in a 37 C thermostat for 24 hours and then taken out to measure the immediate bonding strength.The 2 group of specimens were treated with cold and hot cycles for 3000 times.The micro-tensile bonding strength of each group of specimens was measured,the number of fracture modes was recorded,and the micro-morphology of bonding interface was observed by scanning electron microscopy.Results:1.For the test of micro-tensile bonding strength(unit:MPa)of specimens using adhesive A,the immediate strength of blank group and experimental group were 24.71±4.52 and 26.68±3.07,and the bonding strength of blank group and experimental group after aging was 17.34±3.67and 33.28±2.97.The instant strength of the blank group and the experimental group used adhesive B were 32.47±6.18 and 30.83±2.35,the bond strength of the blank group and the experimental group after aging was 25.53±4.61 and 41.05 ±7.89.Statistical analysis showed that there was no significant difference in the bonding strength between the two different adhesives in the immediate group and the untreated dentin after DMSO pretreatment(P>0.05).There was significant difference in the bonding strength between the experimental group and the blank group after aging treatment(P<0.05).No matter what kind of adhesives,the bond strength decreases significantly after aging treatment,but DMSO pretreatment improves the bond strength after aging.2.There were significant differences between the blank group of adhesives A and the blank group of adhesives B in terms of immediate bonding strength and bonding strength after aging treatment(P<0.05).3.Statistical analysis showed that there was no significant difference in the number distribution of fracture modes among 8 groups(P>0.05).Scanning electron microscopy(SEM)showed that a thicker and more obvious mixed layer appeared in group A after DMSO pretreatment,and the interface between the adhesive and dentin in group B was no longer clear after DMSO pretreatment.After aging treatment,cracks appeared at the bottom of HL layer irn blank group,most obvious in A bonding agent,while HL in DMSO experimental group of B bonding agent hardly changed.Conclusions:1.5%DMSO pretreatment had no effect on the immediate bonding strength of resin-dentin,but significantly increased the bonding strength of dentin after aging.There was no significant difference in the fracture mode between the experimental group and the blank group regardless of aging treatment.Therefore,DMSO pretreatment had the potential to improve the durability of resin bonding,and improved the HL structure of dentin in the use of adhesives A.2.Both the immediate bonding strength of dentin and the bonding strength after aging treatment,Single Bond Universal is superior to Adeper Easy One.Scanning electron microscopy shows that the bonding interface between Single Bond Universal and dentin is more sufficient,but there is no difference in the fracture mode.