Analysis of infinity optical thickness between nine kinds of composite resins with the same color mark

Objective This study compared the infinity optical thickness of composite resins with the same color marks.Methods In this test nine composite resins(shade A2)were used.A plastic mold(10mm in diameter,4mm in height)was used to prepare27disk specimens.Color was measured by CIE L*a*b*relative to CIE source against a white and a black background,using a colorimeter.Color difference(△E*)was calculated as△E=〔(△L*) 2 +(△a*) 2 +(△b*) 2 〕 1/2 .The heights of composite resins were recorded as△E≈1.5.The infinity optical thickness of composite resins when△E=1.5was calculated by regression formulation.Results The results indicated that composite resins with hybrid filler and opaque pigments were superior infinity optical thickness.Composite resins contain micro-filler were inferior infinity optical thickness.Conclusion Although composite resins with the same color mark had the similar fillers,they had different color and infinity optical thickness.