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OBJECTIVE@#To study microstructure, friction and wear behaviors of silicon-lithium spray coating on the surface of zirconia ceramics and to preliminarily evaluate its esthetic so as to provide support and guidance for the clinical application.@*METHODS@#Zirconia ceramic specimens were randomly divided into three groups: coating group (two subgroups), polishing group (two subgroups), and glazing group (four subgroups), with 10 samples in each subgroup. The two subgroups of coating group were the zirconia ceramics with the untreated and preliminary polishing surfaces sprayed with silicon-lithium coating, respectively. The two subgroups of polishing group were preliminary polishing and fine polishing of zirconia ceramics, respectively. The four subgroups of glazing group were preliminarily polished zirconia ceramics glazed with Biomic and Stain/Glaze products, respectively; and untreated zirconia ceramics glazed with Biomic and Stain/Glaze products, respectively. The above 8 subgroups of zirconia ceramic specimens were used as friction pairs with 80 steatite ceramics for 50 000 chewing cycles under 50 N vertical load and artificial saliva lubrication using chewing simulation. Scanning electron microscope was used to observe the microstructure of the surface and section of the coating group, and the thickness of the coating and glazing were measured. The linear roughness of the coating and polishing groups was mea-sured using a laser confocal scanning microscope. Vickers hardness was measured using a microhardness tester and the esthetic of zirconia ceramic full crown sprayed with silicon-lithium coating was preliminarily evaluated. White light interferometer was used to measure the width, the maximum depth and the volume of the wear scars of each group, and the wear depth of steatite ceramics and wear rate of zirconia ceramic specimens were calculated. Kruskal-Wallis nonparametric test and Dunn's multiple comparisons test were used to analyze the wear depth of each group (α=0.05).@*RESULTS@#The microstructures of the silica-lithium spray coatings on the untreated and preliminarily polished zirconia ceramic surfaces showed the protruding defects, and the line roughness of coating group was larger than that of the polishing group. The median thickness of the silica-lithium spray coating on the preliminarily polished zirconia ceramic was 13.0 μm (interquartile range, IQR: 11.6, 17.9), while that of the silica-lithium spray coating on the untreated zirconia ceramic was 4.4 μm (IQR: 4.1, 4.7). The Vickers hardness and wear rate of the coating group were between the polishing group and the glazing group. The wear depths of the wear scars of steatite ceramics were the glazing group, coating group, and polishing group in descending order, and there was statistically significant difference between glazing and polishing groups (P < 0.05). With the increase of polishing procedure, the wear depth of steatite ceramics decreased in each subgroups. The orders of maximum depth and volume of wear scars of zirconia ceramic were the glazing group, coating group, and polishing group in descending order, and there was statistically significant difference in the maximum depth of wear scars between glazing and polishing groups (P < 0.05).@*CONCLUSION@#The silica-lithium spray coating on the zirconia ceramic, can be used as a new method for zirconia ceramic surface treatment, because it can increase the esthetic of zirconia ceramics compared with polishing and reduce the wear of steatite ceramics compared with glazing.
Subject(s)
Humans , Silicon , Materials Testing , Friction , Lithium , Cicatrix , Surface Properties , Silicon Dioxide , Zirconium/chemistry , Ceramics , Dental PorcelainABSTRACT
Objective: To explore the differences of wear resistance of three kinds of glass ceramics and Wieland Zenostar zircona (Zenostar). and to clarify their influencing factors. Methods: Zenostar were made into flat-shaped specimens (zirconia base sample group) and hemisphere-shaped specimens (zirconia pair grinding group). There kinds of glass ceramics IPS Empress (Empress). IPS e. max CAD (e. max). VITA Suprinity (Suprinty) were used as base specimens. Each group was exposed to UMT-2 testing machine to simulate the clinical service. The wear depthes of base specimens were detected by laser confocal scanning. Scanning electron microscope (SEND was used to evaluate the wear surfaces. Results: In zirconia base sample group, there were no significant differences in the maximum wear depthes to Zenostar between the three kinds of glass ceramics ( P>0. 05). In zirconia pair grinding group, the maximum wear depthes ranked as follows: Zenostar group0. 05). but there were significant differences between other groups ( P
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Objective:To explore the differences of wear resistance of three kinds of glass ceramics and Wieland Zenostar zircona (Zenostar) , and to clarify their influencing factors.Methods:Zenostar were made into flat-shaped specimens (zirconia base sample group) and hemisphere-shaped specimens (zirconia pair grinding group) .There kinds of glass ceramics IPS Empress (Empress) , IPS e.max CAD (e.max) , VITA Suprinity (Suprinty) were used as base specimens.Each group was exposed to UMT-2testing machine to simulate the clinical service.The wear depthes of base specimens were detected by laser confocal scanning.Scanning electron microscope (SEM) was used to evaluate the wear surfaces.Results:In zirconia base sample group, there were no significant differences in the maximum wear depthes to Zenostar between the three kinds of glass ceramics (P＞0.05) .In zirconia pair grinding group, the maximum wear depthes ranked as follows:Zenostar group＜e.max group≈Empress group＜Suprinity group;there was no significant difference between e.max group and Empress group (P＞0.05) , but there were significant differences between other groups (P＜0.01) .The SEM results showed that the wearing surface of the Zenostar in zirconia base sample group was relatively smooth;whereas the wearing surface of Empress in zirconia pair grinding group was rougher with alarge area of clebris desquamation surface.Conclusion:The wear resistance of the three kinds of glass ceramics to Zenostar is related to the compositions and the chemical structures of materials.
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Objective:To compare the wear resistance between dentin and dental restoration material in vitro.Methods:The friction and wear behaviors of natural tooth dentin respectively against highly polished polymer ceramic,glass ceramic and zirconia were investigated in an artificial saliva test environment by UMT-2 friction and wear testing machine.Worn surface morphology was observed by scanning electron microscopy(SEM),roughness was measured by roughness instrument,the rigidity value was weighed by electronic balance.Results:The roughness of the 3 materials was similar to that of dentin(P ＞ 0.05),the rigidity of dentin was less than that of the 3 materials (P ＜ 0.05).After friction and wear test,the abrasion quantity of dentin respectively against the 3 materials was less than that of the materials (P ＜ 0.05).There was positive correlation between the wear loss and the hardness of the 3 materials and dentin(r =0.846).The mass loss of the dentin against Poly Ceramic after grinding abrasion was the closest among the 3 materials.Conclusion:Different materials have varying degrees abrasion against dentine.The Polymer Ceramic has closer abrasion performancez with dentin than the other 2 materials.
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Objective:To evaluate the wear resistance of four types of composite resin when they were opposed by human enamel antagonist. The relationship between pH value and wear resistance was also evaluated. Methods:Mutual wear between four types of composite resins(3 mm?20 mm?1 mm),Beautifit(B),SureFilTM(S),TE-Econom(T),Charisma (C),with same rough surface and opposing enamel was evaluated using a wear simulator of UMT-2 (n=10).Wear resistance was assessed as weight loss(g).The worn surfaces were observed with scanning electron microscope(SEM).All data were statistically analyzed with SPSS14.0.Results:SEM observation showed that the fillers particles of resin B,S were bigger than that of the others. Fillers of resin C was the smallest and the most well-distributed. Many filler particles were lost. In the acid environment,the enamel surface had the special appearance. The S,C,T composite resins were less worn. The weight loss of the T,B,S composite resins increased when pH value fell down to 4.0 (P0.05).Conclusion:The wear resistance among the different brands of composite resins are discrepant. The weight loss might be accelerated with the decreased pH value.