Preliminary Study On The Bonding Effect Of A Novel Ceramic Liner And Veneer Porcelain Made With The Negative Thermal Expansion Material Zr₂WP₂O₁₂

ObjectiveBased on the phenomenon that the mismatch of thermal expansion coefficient between decorative porcelain and base porcelain in the clinical zirconia all-ceramic restoration leads to porcelain collapse,the commercial zirconia Cercon Smart ZrO₂and negative thermal expansion material Zr₂WP₂O₁₂ are used to composite the ceramic.A new type of composite lining material was prepared to improve the thermal expansion matching of ceramic veneer and base porcelain in zirconia ceramic restorations,and the bonding effect between the new lining layer material and veneer porcelain was preliminarily investigated.Methods1.Zr₂WP₂O₁₂2 powders were prepared by solid-state sintering and characterized by XRD and thermal expansion properties.2.The composite of Zr₂WP₂O₁₂ and Cercon Smart ZrO₂ in different proportions was characterized by X-ray diffraction and measured by thermal dilatometer.A new type of lining layer which coefficient of expansion between Cercon Smart ZrO₂ and veneer porcelain was found out.3.Based on the parallel shear experiment,the bonding effect of the Novel Ceramic Liner material between zirconia and veneer porcelain was preliminarily investigated.The fracture surface was characterized by scanning electron microscope?SEM?and asana optical microscope?SEM?.Results1.The purity of Zr₂WP₂O₁₂ prepared by solid phase sintering is high,and the negative thermal expansion property is remarkable.2.In the new type of Cercon Smart ZrO₂/Zr₂WP₂O₁₂ lining layer composites,the two substances still exist in their respective phases,and there is no chemical reaction between them.It is found that with the increase of Zr₂WP₂O₁₂ content,the expansion coefficient of the composites decreases gradually.The expansion coefficient of samples containing 1%Zr₂WP₂O₁₂?9.9×10-6/??and 2%Zr₂WP₂O₁₂?9.6×10-6/??is between Zekang commercial zirconia Cercon Smart ZrO₂ and veneer porcelain.3.The shear strength of Cercon Smart ZrO2 and the facing porcelain Vita VM9in the control group was?21.39±2.59?Mpa,the shear strength of the new composite and the facing porcelain Vita VM9 was?20.93±2.95?Mpa,the second group contained 95 wt%of Cercon Smart ZrO₂,2 wt%of the Zr₂WP₂O₁₂ composite material and the facing porcelain Vita VM9,with the shear strength of?18.35±2.95?Mpa.In the observation of the fracture mode of the section,the P=0.695>?=0.05 between the first group and the control group,the difference was not statistically significant;P=0.034<?=0.05 between the first group and the control group,and the difference was statistically significant;and the difference between the second group and the control group was 0.014<?=0.05,and the difference was of statistical significance.Conclusions1.The negative thermal expansion material Zr₂WP₂O₁₂ and new composite lining material can be successfully prepared by solid phase sintering.2.In the new Cercon Smart ZrO₂/Zr₂WP₂O₁₂ composite lining materials with different mass ratios of negative thermal expansion materials,the expansion coefficients of the samples with 1wt%and 2wt%mass ratio are between Zekang commercial zirconia Cercon Smart ZrO₂ and veneer porcelain.3.The content of the negative thermal expansion material,Zr₂WP₂O₁₂,has an impact on the adhesion of the new composite liner layer material to the facing porcelain,containing 96%by weight of Cercon Smart ZrO₂,1%by weight of Zr₂WP₂O₁₂,2%SiO₂,1%Al₂O₃?the first group?and the bonding of the facing porcelain to the same bonding effect as the control group?Cercon Smart ZrO₂?and the facing porcelain...