[Effects of thickness and opaque resin on the color of Artglass].
OBJECTIVE
The purpose of this study was to measure the normal color value and the infinite optical thickness value of Artglass DA3,and evaluate the effect of different thickness and the use of opaque resin on the color values of Artglass.


METHODS
A Minolta CS-321 portable colorimeter was used for color value measurement. The CIE L*a*b* color system was used to describe the color of specimens. Color difference,quantitated in deltaE units, were determined according to the following formula: DeltaE=[(DeltaL)(2)+(Deltaa)(2)+(Deltab)(2)](1/2). DeltaE values below 1.5 was used as being identical for human eyes. Artglass disks with a thickness of 4.0 mm were fabricated and the normal color value were obtained by two specimens pile up. Fifteen groups of specimens of 0.5 to 4.0 mm were made and the color of them were measured on the white and metal background color. The specimens used opaque resin with the thickness of 1.5 to 3.5 mm were determined by colorimeter.


RESULTS
The normal color values of Artglass DA3 were L* 61.23,a* -1.18,b* 11.29. The infinite optical thickness value of Artglass DA3 was 2.75 mm. The opaque resin can increase the values of L*a*b* of Artglass. The effect will disappear until the thickness reaches 2.50 mm.


CONCLUSIONS
From this study, we conclude that the color values of Artglass have a negative correlation between thickness when the background color is white. Thickness and opaque resin have significant effect on the color values of Artglass.
Zhang
Qing-lei
QL
Department of Dentistry, General Hospital of Shanghai Armed Police, Shanghai 201103, China. qingleizhang2003@163.com
Chen
Ji-hua
JH
D003116:Color; D003188:Composite Resins; D003793:Dental Restoration, Permanent; D005899:Glass Ionomer Cements; D006801:Humans; D012823:Silicate Cement
D003188:Composite Resins; D005899:Glass Ionomer Cements; C111282:dental polyglass; D012823:Silicate Cement