| Objectives Brush the flexible ceramic coatings with different thickness on the dentin surfaces,and study the surface characteristics,adhesive properties and wear resistance of them,in order to provide new methods and ideas for the treatment of different degrees of tooth wear.Methods 1 Preparation and grouping of test specimens:by precision cutting machine and high speed turbine,the isolated teeth were prepared into 37 dentin and 5 enamel cylindrical specimens with a diameter of 9mm and a height of 4mm.Divided 37 dentin specimens into three groups by random number table（28 in experimental group,4 in control group for bond strength test,5 in control group of wear resistance test）.Divided 28 specimens in the experimental group into four subgroups randomly（A1～A4 groups）,and brushed flexible ceramic coatings with thickness of 100μm,200μm,500μm and 1000μm,respectively.The bond strength of 4 specimens in the control group was tested,and the surface of the control groups were brushed Super-Bond C&B with thickness of 100μm,200μm,500μm and1000μm,respectively.The surfaces of the 5 dentin and 5 enamel specimens in the group of wear-resistance test were not processed.2 Coating characterization:the micro-surface was observed by scanning electron microscopy;the phase structures of flexible ceramic coatings with different thickness were analyzed by X-ray diffraction,the elemental analysis was carried out by energy dispersive spectrometry.3 Bond strength test:the specimens of A1～A4 groups（one specimen is selected from each group）and B1～B4groups were all bonded to resin block.Using precision cut into 9 cuboidal specimens.The micro-tensile bonding strength was tested by universal testing machine.The morphology of the bonding surface was observed by scanning electron microscope and the fracture mode was analyzed.4 Wear resistance test:using a friction and wear test machine,in artificial saliva conditions,the reciprocating friction and wear experiments of different thickness of flexible ceramic coatings,dentin and enamel specimens with Si3N4 spheres were carried out,respectively,the friction coefficients were recorded.The three-dimensional morphology of wear spots was observed by white light interferometer and the volume loss was calculated.The micro-morphology of wear spots was observed by scanning electron microscopy.Results 1 Coating characterization:the results of scanning electron microscope shows that the surface structure of the ceramic coating is dense and smooth,and the ceramic particles are dispersed on the surface of the coating,and there is no significant difference of the superficial morphology of each coating;the flexible ceramic coatings with different thickness contain Al,Ti,Si,C and O elements,in which the concentration of Al element is the highest and decreases with the increase of coating thickness.The main peak of the coating with different thickness isα-Al2O3.In addition,it also contains rutile Ti O2,Si O2and some organic components.2 Bond strength test results:the bonding strength of flexible ceramic coatings with different thickness are equal to that of Super-Bond C&B.The bonding strength of the coating with a thickness of 1000μm is lower than that of100μm and 200μm.There is no significant difference in the morphology of the bonding interface between the coating and dentin with the thickness of 100μm,200μm and 500μm,but the bonding is looser when the thickness is 1000μm.3 Wear resistance test results:the friction coefficient of A1 group is slightly lower than that of dentin,while that of A2,A3and A4 groups was higher than that of dentin and close to enamel,and the friction coefficient increased with the increase of thickness;The three-dimensional topography of wear spots shows that the shapes of wear spots with thickness of 100μm and 200μm are similar,and that of coating with thickness of 500μm and 1000μm are similar to that of dentin,and the shapes are long and oval.The depth of wear spot increases with the increase of coating thickness,but they are smaller than that of dentin.;the measurement results of volume loss shows that the loss of dentin is the largest(11.58×10-3±7.84×10-4)and the volume loss of enamel is the smallest(1.47×10-3±1.15×10-4).The wear volume of ceramic coating with different thickness within that of enamel and dentin.The wear volume of 1000μm coating is the largest,and the wear volume of the coating with 100μm or 200μm is closer to that of the enamel.Conclusions 1 The flexible ceramic coatings with different thickness are applied to the dentin,the coating with compact and smooth surface and uniform dispersion of ceramic particles can be obtained.2 The flexible ceramic coating with different thickness has good bonding strength with dentin,but the bonding strength will be better when the coating thickness is 100μm、200μm or 500μm.3 The wear resistance of flexible ceramic coatings with different thickness are all better than that of dentin.The coatings with thickness of100μm and 200μm are more wear-resistant.Figure 9;Table 5;Reference 122... |
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