지르코니아 코아의 색조부여가 전부도재관의 색조에 미치는 영향에 대한 분광측색분석 = Spectrophotometric analysis of the influence to shade of zirconia core on the color of ceramic

다국어 초록 (Multilingual Abstract)

Statement of problem: At all times people have tried to fabricate tooth restorations using tooth colored materials. Recently, demands for esthetics, even in restorations requiring strength, has brought a revolution to dentistry and increased use of zirconia. The basic color of zirconia is white to ivory. The color can be partially adapted by veneering it with ceramic materials. However, it would be better if the substructure could already be adapted to the basic color shade of neighboring teeth. By adaptation to the basic shade, it can help to reduce the necessary layer thickness of the veneer ceramic to achieve the desired color. Purpose: The purpose of this study was to spectrophotometrically evaluate the influence of shading of zirconia core on the final shade of all-ceramic restorations using the CIE $L^{*}a^{*}b^{*}$ system. Material and methods: Core specimens (n = 20 per group) of Lava Frame Zirconia, KaVo Everest Zirconia, Digident CAD/CAM Zirconia were fabricated at 20 mm in diameter and 0.5 mm in thickness. Halves of each groups were shaded in A3 color. These core specimens were veneered with A3 porcelain of the recommended manufacturer at thickness of 0.5 mm. CIE $L^{*}a^{*}b^{*}$ coordinates were recorded for each specimen with a spectrophotometer (Model CM-2600d, Minolta, Japan) at 0.5 mm, 0.4 mm, 0.3 mm in thickness. Color differences were calculated using the equation ${\Delta}E^{*}=[({\Delta}L^{*})2+({\Delta}a^{*})2+({\Delta}b^{*})2]1/2$. Results: 1. In the case where porcelain layer has a thickness of 0.5 mm, Lava Frame Zirconia and KaVo Everest group did not show clinically perceived color difference, however Digident CAD/CAM Zirconia group showed clinically perceived color difference according to shade allowed on core. 2. When the thickness of porcelain layer decreased from 0.5 mm to 0.4 mm, Lava Frame Zirconia and KaVo Everest group did not show clinically perceived color difference, on the other hand Digident CAD/CAM Zirconia group showed clinically perceived color difference according to shade allowed on core. 3. When the thickness of porcelain layer decreased from 0.5 mm to 0.3 mm, clinically perceived color differences were observed from all three groups. Conclusions: Ziroconia system, which is possible to allow shade on core, are thought to be much more favorable to reproduce natural shade compared to systems that is impossible to give shade. Therefore, clinicians ought to choose adequate system for certain clinical situation by considering above specific character.

참고문헌 (Reference)

• 1 Devigus A., "hading Vita YZ substructures : Influence on value and chroma, Part I." 7 : 293-301, 2004
• 2 Suárez MJ., "Threeyear clinical evaluation of In-Ceram Zirconia posterior FPDs" 17 : 35-38, 2004
• 3 Shin YM., "The effect of core : type and thickness ratio on the strength of all ceramic crown" Kyung Hee University 2006
• 4 Bangston LK., "The conversion of chromascan designations to CIE tristimulus values" 48 : 610-617, 1982
• 5 Kim YH., "Study on the color stability of veneer resin" 16 : 1-5, 1991
• 6 Pae AR., "Spectrophotometric analysis of the influence of zirconia core on the color of ceramic" 43 : 466-477, 2005
• 7 Lee SO., "Spectrophotometric analysis of the influence of metal substrate on the color of ceramic" 41 : 148-159, 2003
• 8 Seghi RR., "Spectrophotometric analysis of color differences between porcelain systems" 56 : 36-40, 1986
• 9 Devigus A., "Shading Vita YZ substructures : Influence on value and chroma, Part II." 7 : 379-388, 2004
• 10 Crispin BJ., "Relative color stability of ceramic stains subjected to glazing temperatures" 66 : 20-23, 1991
• 11 Wozniak WT., "Proposed guidelines for the acceptance program for dental shade guides" American dental association 1-2, 1987
• 12 Kim KI., "Introduction to color science" Daekwang 1999
• 13 Kim IJ., "Effect of surface topography on the color of dental porcelain" 14 : 405-409, 2003
• 14 Douglas RD., "Color stability of new-generation indirect resins for prosthodontic application" 83 : 166-170, 2000
• 15 Tamura K., "Ceramo-metal crown" Ishiyaku Publishers. Inc. 1991
• 16 Johnston WM., "Assessment of appearance match by visual observation and clinical colorimetry" 68 : 819-822, 1989
• 17 O’Brien WJ., "A new, small-colordifference equation for dental shades" 69 : 1762-1764, 1990