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<p><b>OBJECTIVE</b>To investigate the influence of background color on veneered In-Ceram and Cercon dental ceramics including Vita In-Ceram Electroformed Alumina (AL2), Electroformed Zirconia (Z21), Cercon base color Zirconia and Cercon base Zirconia.</p><p><b>METHODS</b>The colorimetric values of all the materials on noble metal, Ni-Cr alloy, silver amalgam and resin background were measured with a spectrocolorimeter, and the color difference among the groups was calculated.</p><p><b>RESULTS</b>After veneered, the color difference of Z21 Electroformed Zirconia was more distinct against the background of silver amalgam than against the backgrounds of noble metal and resin, but the color differences of the 4 veneered dental ceramics against different backgrounds were unidentifiable by human eyes (δE<1.5).</p><p><b>CONCLUSION</b>After veneered, AL2 electroformed alumina, Z21 electroformed zirconia, Cercon base Zirconia and Cercon base color Zirconia are less influenced by the background color, and covering the background color is therefore not necessary.</p>
Subject(s)
Color , Dental Materials , Dental Prosthesis DesignABSTRACT
Objective To reconstruct three-dimensional finite element analysis all-ceramic crowm model of the first maxillary molar.Methods After the CT scanning and image processing to the first maxillary molar in vivo,a 3-D geometric model was established by the Imageware software.The mesh model was then built in Abaqus,the finite element analysis software.Result The three dimensional finite element all-ceramic crown models of the first maxillary molar was constructed on the computer,which had 60 160 nodes and 186 328 tetrahedrons elements.Conclusion The finite element model constructed has the advantages of intact structure and precise elements,can simulate the natural condition and facilitate the further biomechanical research.
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objective: To investigate the effects of cerium oxide content on the color of alumina glass composite. Methods: Infiltration glass powder with different content of cerium oxide (1%～4%) were fabricated. Alumina glass composite was prepared by infiltrating molten glass into presintered alumina block at 1 250 ℃ for 2 h, and the color of the alumina glass composite were measured with Minolta chromatic instrument(CR 321) . For comparison, the color of VITA In Ceram alumina technical shade guide was recorded too. Results: After infiltration, the b * range of the alumina glass composite was in accord with that of the shade guide. With the increasing content of the cerium oxide, a *, b * and chroma increased, L * decreased, the hue of the alumina glass composite shifted from yellow green to yellow red. Conclusion: Cerium oxide may effectively enhance b * of the alumina glass composite, but its ability of reducing L * and enhancing a * is weak.
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Objective: To measure the color of dental CAD/CAM alumina-glass-composites(AGC). Methods: Dental CAD/CAM alumina block were infiltrated at 1 120 ℃ by laboratory made AG1,AG2,AG3 and AG4 color serials of infiltration glass powder and Vita In-Ceram Alumina AL1,AL2,AL3 and AL4 infiltration glass respectively. Specimens were made with the area of 10 mm?10 mm,thickness of 0.5,1 and 1.5 mm respectively. Color parameters were measured by Minolta CM-2600d spectrophotometer. Results:The specimen with the thickness of 1 mm was used as the standard for color measurement.After infiltration with AL1-AL4 glass powder,the color parameters of Vita alumina core ceramic were L*: 69.39-78.41,a*:1.82- 4.02,b*:18.35-24.42,when infiltrated with AG1-AG4 glass powder, the color parameters of CAD/CAM AGC were L*:68.80-78.44,a*:1.32- 4.75,b*:16.85- 21.86. b*value and chroma of the AG3 core ceramic were lower than that of AL3 core ceramic,while a* value was higher.b* value and chroma of the AG1 and AG2 core ceramic were lower than that of AL1 and AL2 core ceramic. The reflectance curve of CAD/CAM AGC infiltrated by AG1-AG4 glass powder demonstrated the similar trend as that of the core ceramic infiltrated by Vita In-Ceram glass powder. Conclusion: The color range and surface reflection rate of laboratory made AG1-AG4 AGC are similar with those of Vita AL1-AL4 In-Ceram Alumina core and may meet the need of color match with veneer ceramics.