Translucency comparison of CADCAM materials and the effect of core material on the overall translucency and color of coreveneer complex
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Part I: Translucency comparison of full contour and core materials Purpose: This study aims to compare the translucency of different CAD/CAM materials and study the change of translucency as a function of thickness. Materials and methods: Seven CAD/CAM core materials were tested: a.Lava (3M/ESPE); b.Incoris ZI (Sirona); cYZ (Vita Zahnfabrik); d.Cercon (Dentsply); e.Inceram spinell (Vita Zahnfabrik); f. Inceram alumina (Vita Zahnfabrik); g. Inceram zirconia (Vita Zahnfabrik) (n=5). Five full-contour "chair-side" CAD/CAM block material were also chosen to be tested: a.Paradigm C (3M/ESPE); b. Vita bloc mark II (Vita Zahnfabrik); c.IPS E.max CAD (Ivoclar,Vident); d. Empress CAD HT and e.Empress CAD LT (Ivoclar, Vident) (n=5). Contrast ratio measurements of core and full contour materials were determined on disc specimens 0.5 and 0.7mm thick (for core) and 1.5mm thick (for full contour) materials. The specimens were prepared by sectioning blocks of each material with a diamond saw.Specimens of Lava, Incoris ZI, YZ and Cercon specimens were sintered. Inceram specimens were glass infused and IPS e.max CAD specimens were fired for crystallization according to manufacturers' instructions. An additional experimental group of ten IPS e.max CAD specimens were fired for two and three firing cycles (n=5). All specimens were tested in a tri-beam diffuse 8 degree observer function spectrophoto meter (i5, X-Rite, Gretag Macbeth) across the visible spectrum (400-700 nm) with CIE standard illuminant D65. Contrast ratios (CR) were calculated from the luminous reflectance of the specimens on a black surface (Rzero) compared to the luminous reflectance on a white surface (Rr), (CR= Rzero/ RR). IPS E.max CAD speciments, that were fired for additional cycles, were also measured for CIE L*A*B* Values against a white background. Statistical analysis: One-way analysis of variance (ANOVA) was performed to determine the presence of significant differences among the materials in each group. Tukey's and Borferroni's multiple-comparison tests were used to analyze the data at a level of significance of 0.05. [Delta]E values were calculated for IPS.Emax CAD specimens that were experimentally fired for additional cycles, to determine coIor changes. Results: (ANOVA) test revealed differences within both groups of materials. At alpha=0.05 Tukey's and Bonferroni's multiple comparison indicated the following rankings of materials according to contrast ratio (from most translucent to most opaque). Core materials: Inceram spinell 0.52 (0.07) [more than] Lava 0.689 (0.03) and YZ 0683 (0.013) [more than] Inceram alumina 0.702 (0.02) [more than] Cercon 0.738 (0.015) and Incoris ZI 0.752 (0.012) [more than] Inceram zirconia 0.99 (0.001). Increasing the thickness of the core materials from 0.5 to 0.7 mm resulted in a significant increase in the contrast ratio (decrease in translucency) (P[less than] 0.05) for all the core materials tested except Inceram zirconia. Full contour materials: Empress CAD HT 0.69 (0.015) [more than] Paradigm C0.66 (0.012) and Vita bloc mark II 0.69 (0.008) [more than] Empress CAD LT 0.74 (0.022) [more than] IPS E.max CAD 0.82 (0.003). Additional firing of IPS E.Max CAD for one and two additional cycles lead to a significant increases in Contrast Ratio value (P[less than]0.05). IPS E.max CAD specimens exhibited color changes upon additional firing. This color change was visually detectable only between one and three firing cycles ([Delta]E=3.0 1). Part II: The Effect of Core Material on the Overall TransIucency and Color of Core/Veneer Complex Purpose: The aim of this part of the study is to evaluate the effect of different core materials and thickness of veneering porcelain on the overall translucency and color of core/veneer complexes. Materials and methods: Three core materials were used in this part of the study. The materials are: Cercon (Dentsply), Inceram Alumina (Vita Zahnfabrik) and high noble alloy (Aurix, Vita Zahnfabrik). The core materials were veneered with 0.5, 1.0 and 1.5 mm thickness of veneering porcelain; VM9, VM7 and VM13 (Vita Zahnfabrik), respectively. All specimens were tested in a tri-beam, diffuse function spectrophotometer (i5, X-Rite, Gretag Macbeth) in the visible spectrum range of 400-700nm with CIE standard illuminant D65. Contrast ratios (CR) were calculated from the luminous reflectance of the specimens on a black surface (R。) compared to the luminous reflectance on a white surface (RR), (CR= Rzero/RR). CIE L*A*B* values were obtained for each specimen measured over a white backing. Delta E values were calculated to measure color differences between specimens. Statistical analysis: Two-Way-analysis of variance was performed to assess the presence of interaction between the different core materials and veneering porcelain thickness. One-way analysis of variance (ANOVA) was performed to determine the presence of significant differences among different thicknesses in each core materials group. Tukey's multiple-comparison test was used to analyze the data at a level of significance of 0.05. [Delta]E values were calculated to measure color difference between different pairs of specimens. Results: Porcelain fused to metal restorations revealed constant opacity regardless of veneering porcelain thickness. At 100 mm thickness of veneering porcelain, translucency of the Cercon core did not affect the translucency of the core/veneer complex. Color difference between high noble alloy, Cercon and Inceram alumina is detectable when veneered with 0.5mm porcelain. When the thickness of veneering porcelain is increased to 1.0 and 1.5mm, Inceram alumina and Cercon veneered cores had a small color difference ([Delta]E=1 .01,2.29), respectively. PFMs specimens showed a large color difference at 1.O and 1.5mm thickness of veneering porcelain compared to the other cores.
PLEASE NOTE: This work is protected by copyright. Downloading is restricted to the BU community: please click Download and log in with a valid BU account to access. If you are the author of this work and would like to make it publicly available, please contact firstname.lastname@example.org.Thesis (MSD)--Boston University, Henry M. Goldman School of Dental Medicine, 2008 (Dept. of Restorative Sciences and Biomaterials).Includes bibliographical references: leaves 96-99.
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