| Objectives The epoxy ceramic material is introduced into the oral field for in vitro experimental research.The adhesive properties of epoxy resin ceramics with natural dentin are tested,and the wear resistance and biocompatibility are evaluated to provide a new idea for preventing and treating tooth wear problems.Methods 1 Bonding performance test: using high speed turbine,in the water spray state,remove the oeclusal enamel.The exposed part of the dentin was cut into 40 pieces of teeth,having a thickness of not less than 2 mm,and the surface was polished.The teeth were randomly divided into 4 groups(n=10).The dentin surfaces of groups A,B and C were treated as follows: no treatment on the surface,treatment with dentin etchant in SuperBond C&B,37% orthophosphoric acid deal with.Then Groups A,B,and C were respectively coated with the epoxy resin ceramic.Group D was used as a control group,and the surface of dentin was treated with a dentin etchant in Super-Bond C&B,and then brushed with Super-Bond.After analyzing the surface morphology of each group of coatings,the adhesive strength between coating and dentin was evaluated by scratch tester.2 Wear resistance test: A test piece of d=10 mm,h=50 mm was prepared from enamel,dentin,epoxy ceramic coating and Super-Bond C&B.In artificial saliva conditions,four sets of test pieces were placed in a micro-friction and wear test machine,and respectively etched with talc porcelain,the dynamic friction coefficient was recorded,and the volume loss was calculated.3 Scanning electron microscopy was used to observe the surface morphology of the material before and after the scratch test and wear resistance test.4 The biocompatibility of epoxy resin ceramic was detected by MTT assay.The cytotoxicity of epoxy resin ceramic coating was evaluated by observing the Proliferation rate of L929 cells.Results 1 Bonding performance test results: Under the scanning electron microscope,the ceramic coating is tightly bonded to the dentin.One-way ANOVA analysis of variance and pairwise comparison showed that the difference between group C and group D was not significant(P>0.05),and group C and group D were significantly higher than group A and group B(P<0.05).2 Wear resistance test results: 1)The friction coefficient of epoxy resin ceramic group and enamel group were similar and the friction coefficient of Super-Bond group is smaller than that of enamel group.2)Volume loss: The volume loss was from the top to the bottom: Super-Bond group,dentin group,enamel group and epoxy resin ceramic group.There was no significant difference in the volume loss between the epoxy resin ceramic group and the enamel group(P>0.05).The difference between the other groups was statistically significant(P<0.05).3 Surface micromorphology: 1)Before and after scratching: There is no difference in surface topography before scratching in groups A,B and C.After scratching in groups A,B and C,the image shows brittle and ductile behavior,and the scratched track shows plow shape along thescratching path.Forms cracks,debris and wear debris.The D-scratch path mainly exhibits brittleness and is plow-shaped.2)After wear test: epoxy resin is mainly abrasive wear and fatigue wear;Super-Bond is mainly adhesive wear.4 Cytotoxicity test results:the L929 cells cultured in the epoxy resin ceramic group had normal morphology and good growth state.The cell proliferation rate of the negative control group and the experimental group were significantly higher than that of the positive control group,and the cytotoxicity of the experimental group was grade 0.Conclusions The dentin treated with 37% orthophosphoric acid forms a dense and shiny coating with the epoxy resin ceramic.The coating forms a tight bond with the dentin,and the bonding strength is comparable to Super-Bond;at the same time,the wear resistance of the coating matches the enamel.The results of the cytocompatibility test showed that the coating had no obvious cytotoxicity.Experiments have confirmed that epoxy resin ceramic coating has a good application prospect in the prevention and treatment of dentin wear.Figure 9;Table 5;Reference 117... |
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