Effects Of Surface Modification Of Carbon Nanotubes With Gelatin On Dentin Bonding Stability

Objective:After characterization and cytotoxicity test of carbon nanotube(CNT)modified with gelatin(Gel),the dentin adhesive surface was pretreated with its suspension.The micro-tensile bonding strength and nano-leakage effect of dentin bonding were studied preliminarily.It can provide basic reference for the clinical application of modified carbon nanotubes in enhancing the durability and stability of dentin bonding.Methods:1.According to the surface modification of carbon nanotubes with gelatin by the previous experimental method,it is more appropriate to prepare 20 μg/m L and 40μg/m L CNT@Gel suspension to study in this experiment.2.The freshly extracted third molar was used for bonding repair after exposing the central dentin of the crown.Twelve teeth were selected for bond strength test,and the specimens were randomly divided into 6 groups(n=2),A,a: control group,after acid etching,deionized water(0 μg / m LCNT@Gel)micro-brushed dentin surface plus Single Bond Universal Adhesive,then repaired with resin.B,b: after acid etching,the dentin surface was pretreated with 20 μg/m L CNT@Gel,plus Single Bond Universal Adhesive and repaired with resin.C,c: after acid etching,the dentin surface was pretreated with 40 μg/m L CNT@Gel,plus Single Bond Universal Adhesive and repaired with resin.The micro-tensile bond strength of immediately groups(A,B,C)and simulated aging groups(a,b,c)was tested.3.The other twelve teeth were selected for nano-leakage detection,and the specimens were randomly divided into 6 groups(n=2),A,a: control group,after acid etching,deionized water(0 μg/m L CNT@ Gel)micro-brushed dentin surface plus Single Bond Universal Adhesive,then repaired by resin.B,b: after acid etching,the dentin surface was pretreated with 20 μg/m L CNT@Gel,plus Single Bond Universal Adhesive and repaired with resin.C,C: after acid etching,the dentin surface was pretreated with 40 μg/m L CNT@Gel,plus Single Bond Universal Adhesive and repaired with resin.The nano-leakage of immediately grous(A,B,C)and simulated aging groups(a,b,c)was detected,and the effect of CNT@Gel on the durability and stability of dentin bonding was evaluated.Results:1.The bond strength of immediate groups was A < B < C,there was significant difference between A and B(p < 0.05).There was significant difference between A and C(p < 0.05),too.After simulated aging,the bonding strength was a < b < c.There was significant difference between a and b(p < 0.05).There was significant difference between a and c(p < 0.05),too.Comparing the bond strength before and after simulated aging,it was found that there was significant difference between A and a,B and b(P < 0.05).There was no significant difference between C and c(P >0.05).2.In the immediate groups,the expression of nano-leakage was observed under scanning electron microscope: A > B > C.The expression of nano-leakage in simulated aging scanning electron microscope photos was a > b > c.In both the immediate groups and the aging groups,the expression of nano-leakage on the dentin surface pretreated with CNT@Gel decreased significantly after bonding.Conclusion:The pretreatment of dentin adhesive surface with CNT@Gel can improve the micro-tensile bond strength and reduce the nano-leakage.40 μg/m L CNT@Gel not only has good biocompatibility,but also has a good effect of improving the stability of dentin bonding interface,which may have further research value in the application of dental adhesive materials.