Comparison Of Two Self-etching Adhesives On The Bonding Effect Between Normal Dentin And Glass Ceramics

Objective:This study in vitro aimed to compare the shear bond strength,fracture modes and nanoleakage between normal dentin(ND)and glass ceramics using two self-etching resin adhesives.To evaluate its bond strength and interfacial sealing.Then it can provide references for the selection and application of two self-etching resin adhesives.Methods:Forty human sound maxillary third molars were selected.Flat,mid-dentin surface were obtained by removing the coronal enamel and a small amount of dentin of each tooth with a high-speed diamond saw under water cooling.Dentin surfaces were ground with 600 grit SIC abrasive paper under running water,and then remove the residual dentin around them to obtain forty dentin blocks with a size of 4mm*4mm~2.Forty dentin blocks were divided into two groups A and B by radom digital table method,each group was then divided into two bonding groups randomly.The dentin blocks in group A were bonded with ceramics using two self-etching adehesives of Optibond versa and Multilink N respectively according to manufacturers instructions.The completed bonding specimens were stored in 37℃distilled water for 24 hours.The shear bond strength of specimens was tested by the universal tester.After the shear bond strength test,the fractured dentin surfaces were examined at the stereoscopic microscope(40X)and to determine the patterns of fracture.The fracture surface morphology of the specimens was observed under a SEM.The completed bonding specimens in group B were stored in 37℃distilled water for 24 hours.The specimens were stained with 50%(M/V)ammoniated silver nitrate solution.The interfacial nanoleakage was evaluated by the field emission scanning electron microscope(FESEM)in backscattered electron imaging mode combined with the energy dispersive X-ray spectrometer(EDS).Data were analyzed by the independent sample t test and Fisher exact test(IBM SPSS Statistics ver.26.0,IBM Corp.New York,USA).The statistic significance was set atα=0.05.Results:1.The shear bond strength of specimens were analyzed with the independent sample t test.The result was that:There was a significant difference in the shear bond strength between Optibond Versa and Multilink N(P<0.05).The shear bond strength of Optibond Versa[(20.554±2.506)MPa]was significanly higher than that of Multilink N[(16.433±1.788)MPa].There was no significance difference in fracture type between the two groups by Fisher exact test(P>0.05).2.The interfacial nanoleakage of specimens were analyzed with the independent sample t test.The result was that:There was a significant difference in the interfacial nanoleakage between Optibond Versa and Multilink N(P<0.05).The interfacial nanoleakage of Optibond Versa[(14.593±11.795)%]was significanly lower than that of Multilink N[(24.898±11.923)%].Conclusions:1.The bonding strength of Multilink N is significantly lower than that of Optibond Versa;2.The interfacial sealing effect of Optibond Versa is better than Multilink N.