[Study on the infinity optical thickness of light-cured composite resins and attached shade guides].
OBJECTIVE
This study compared the opaque characteristics of light-cured composite resins and attached shade guides.


METHODS
Three kinds of light-cured composite resins and attached shads guides were used. A plastic mold (10mm in diameter and 4mm in height) was used to prepare disk specimens. Color was measured by CIE L*a*b* relative to CIE source against a white and a black background, using a colorimeter. Color change (DeltaE)was calculated as DeltaE=[(DeltaL*)(2)+(Deltaa*)(2)+(Deltab*)(2)](1/2). The heights of composite resins were recorded as DeltaE is approximately 1.5. The infinity optical thickness of composite resins when delta E*=1.5 was calculated by regression formulation.


RESULTS
There was significant difference in color difference and the infinity optical thickness among materials and shades. The infinity optical thickness gradual decreased in the same shade mark from 1 to 4, and from A to D the results was not simple.


CONCLUSIONS
There was significant difference in the infinity optical thickness between the attached shade guides and the resins materials. Composite resins contain micro-filler were inferior in infinity optical thickness.
Xia
Chun-ming
CM
Department of Prosthet, Stomatological Hospital, Fourth Military Medical University, Xi'an 710032, China. xia889325@163.net
Shi
Chang-xi
CX
Chen
Ji-hua
JH
Yu
Jie
J
Wang
Yan
Y
Wang
Jun-li
JL
Wang
Ying
Y