Shoji Takenaka1, Rika Wakamatsu, Yumiko Ozoe, Fumihito Tomita, Masayoshi Fukushima, Takashi Okiji. 1. Division of Cariology, Operative Dentistry and Endodontics, Department of Oral Health Science, Niigata University Graduate School of Medical and Dental Sciences, 2-5274, Gakko-cho-dori, Chuo-ku, Niigata 951-8514, Japan. takenaka@dent.niigata-u.ac.jp
Abstract
PURPOSE: To estimate the color-masking ability of two polymer-based paint-on temporary coating materials, White Coat and BeautiCoat. METHODS: Three shades (OA1, OB0, OB1) of White Coat and four shades (BW1, BW2, BW3 and BW4) of BeautiCoat were used. Disk specimens (0.25-2.0 mm thick) were prepared, CIELAB coordinates (L*, a*, b*) were measured against white and black backgrounds on a colorimeter, and translucency parameter (TP) was calculated. Masking effect (deltaME*ab) was also calculated as the color difference between a specimen over a black background and black background itself. Measurements were also made on a dentin-shaded resin composite as a substitute for discolored teeth, and color differences (deltaE*) were then calculated. RESULTS: The TP value decreased as the thickness of the specimen increased, and non-linear regressions were shown between the specimen thickness and TP value for all materials evaluated (P < 0.01). TP values of BeautiCoat showed significant differences (P < 0.05) between each shade at any thickness evaluated, ranging from 20.0 to 46.4 at 0.25 mm in thickness. White Coat showed narrower-ranging TP values: from 20.0 to 23.5 at 0.25 mm, and differences were often insignificant. deltaME*ab values correlated with TP values. deltaE* values of 0.25 mm-thick specimens against the dentin-shade composite were above 6.5, which can be evaluated as visually perceptible.
PURPOSE: To estimate the color-masking ability of two polymer-based paint-on temporary coating materials, White Coat and BeautiCoat. METHODS: Three shades (OA1, OB0, OB1) of White Coat and four shades (BW1, BW2, BW3 and BW4) of BeautiCoat were used. Disk specimens (0.25-2.0 mm thick) were prepared, CIELAB coordinates (L*, a*, b*) were measured against white and black backgrounds on a colorimeter, and translucency parameter (TP) was calculated. Masking effect (deltaME*ab) was also calculated as the color difference between a specimen over a black background and black background itself. Measurements were also made on a dentin-shaded resin composite as a substitute for discolored teeth, and color differences (deltaE*) were then calculated. RESULTS: The TP value decreased as the thickness of the specimen increased, and non-linear regressions were shown between the specimen thickness and TP value for all materials evaluated (P < 0.01). TP values of BeautiCoat showed significant differences (P < 0.05) between each shade at any thickness evaluated, ranging from 20.0 to 46.4 at 0.25 mm in thickness. White Coat showed narrower-ranging TP values: from 20.0 to 23.5 at 0.25 mm, and differences were often insignificant. deltaME*ab values correlated with TP values. deltaE* values of 0.25 mm-thick specimens against the dentin-shade composite were above 6.5, which can be evaluated as visually perceptible.