Translucency and masking ability of various opaque-shade composite resins.
OBJECTIVE
The aims of this study were to evaluate the adequate thickness of opaque resins for situations such as an oral black cavity and discolored tooth structure, as well as the translucency of each opaque material at various thicknesses.


METHODS
Six opaque-shade composite resins (Z-350 OA3, Amelogen Universal A2O, Esthet-X A2O, Esthet-X A4O, Charmfil UO, and Aelite Universal OA3) were prepared in metal molds with a hole of 8mm in diameter and various thicknesses (0.5mm, 1.0mm, 1.5mm, 2.0mm, 2.5mm, 3.0mm and 4.0mm). Four backgrounds (white tile, black tile, C4 shade porcelain and opaque resin itself) were used to determine the translucency parameter (TP) (between black and white backgrounds), and to mimic a black oral cavity (between black and opaque resin backgrounds) and a discolored tooth structure (between C4 and opaque resin backgrounds). Color measurements were made by a colorimeter to determine the CIELAB values of each specimen with each background and to calculate the TP and DeltaE* value difference among the specimens on the backgrounds.


RESULTS
TP and DeltaE* obtained between black and opaque resin backgrounds decreased in similar pattern as thickness increased. A C4 background was masked by resin thicknesses of 0.5-1.0mm, while a black background required thicknesses of 1.0-2.0mm.


CONCLUSIONS
This study can provide helpful guidelines for the esthetic restoration of discolored tooth structures or 'through and through' class III and IV cavities with composite resin materials.
Kim
Sung Joon
SJ
Dental Research Institute and Department of Conservative Dentistry, School of Dentistry, Seoul National University, 28-2 Yungeon-Dong, Jongro-Gu, Seoul 110-749, Republic of Korea.
Son
Ho Hyun
HH
Cho
Byung Hoon
BH
Lee
In Bog
IB
Um
Chung Moon
CM
D003116:Color; D003124:Colorimetry / Q000295:instrumentation; D003188:Composite Resins / Q000737:chemistry*; D003764:Dental Materials / Q000737:chemistry*; D003776:Dental Porcelain / Q000737:chemistry; D017267:Dental Prosthesis Design; D006801:Humans; D008027:Light; D008422:Materials Testing; D017797:Prosthesis Coloring; D013499:Surface Properties
C485363:Aelite LS; C511084:Charmfil Flow; D003188:Composite Resins; D003764:Dental Materials; C466112:Esthet-X; C106662:amelogen; C533204:filtek Z350; D003776:Dental Porcelain