Relative translucency of six all-ceramic systems. Part II: Core and veneer materials☆1☆2☆3☆4☆5☆6☆7☆8
Abstract
Statement of Problem. All-ceramic core materials with various strengthening compositions have a range of translucencies. It is unknown whether translucency differs when all-ceramic materials are fabricated similarly to the clinical restoration with a veneered core material. Purpose. This study compared the translucency of 6 all-ceramic materials veneered and glazed at clinically appropriate thicknesses. Material and Methods. Core specimens (n = 5 per group) of Empress dentin, Empress 2 dentin, In-Ceram Alumina, In-Ceram Spinell, In-Ceram Zirconia, and Procera AllCeram were fabricated as described in Part I of this study and veneered with their corresponding dentin porcelain to a final thickness of 1.47 ± 0.01 mm. These specimens were compared with veneered Vitadur Alpha opaque dentin (as a standard), a clear glass disc (positive control), and a high-noble metal-ceramic alloy (Porc. 52 SF) veneered with Vitadur Omega dentin (negative control). Specimen reflectance was measured with an integrating sphere attached to a spectrophotometer across the visible spectrum (380 to 700 nm); 0-degree illumination and diffuse viewing geometry were used. Measurements were repeated after a glazing cycle. Contrast ratios were calculated from the luminous reflectance (Y) of the specimens with a black (Yb) and a white backing (Yw) to give Yb/Yw with CIE illuminant D65 and a 2-degree observer function (0.0 = transparent, 1.0 = opaque). One-way analysis of variance and Tukey's multiple-comparison test were used to analyze the data (P<.05). Results. Significant differences in contrast ratios were found among the ceramic systems tested when they were veneered (P<.0001) and after the glazing cycle (P<.0001). Significant changes in contrast ratios (P<.0001) also were identified when the veneered specimens were glazed. Conclusion. Within the limitations of this study, a range of translucency was identified in the veneered all-ceramic systems tested. Such variability may affect their ability to match natural teeth. The glazing cycle resulted in decreased opacity for all test materials except the completely opaque In-Ceram Zirconia and metal-ceramic specimens. (J Prosthet Dent 2002;88:10-5.)
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☆1 aFormer postgraduate student, Department of Prosthodontics. Private practice, London, England.
☆2 bProfessor and Head, Department of Prosthodontics.
☆3 cAssociate Professor, Department of Family Dentistry.
☆4 dAssistant Professor, Department of Family Dentistry.
☆5 eAssociate Professor, Department of Prosthodontics; Director of Clinical Research, Dows Institute for Dental Research.
☆6 fAssociate Professor, Department of Operative Dentistry.
☆7 This research was sponsored by a 1998-99 American College of Prosthodontists/ESPE Research Fellowship Award in Fixed Prosthodontics, Chicago, Ill. It was presented before the American College of Prosthodontists Annual Session, November 2001, New Orleans, La., and awarded the Sharry Prize for Research from the American College of Prosthodontics.
☆8 Reprint requests to: Dr Michael J. Heffernan, 90 Harley St, London W1G 7HS, UNITED KINGDOM, Fax: (44)20-7224 4158, E-mail: mheffernan@ureach.com
PII: S0022-3913(02)00041-0
doi:10.1016/S0022-3913(02)00041-0
© 2002 Editorial Council of The Journal of Prosthetic Dentistry. Published by Elsevier Inc. All rights reserved.
