Objective To study the effect existed in the course of adopting different thickness and chromatics of various opaques so that a good methods can be provided for clinical care in prosthodontics. Methods A model of using the thin plastic paper to control the ceramic thickness was applied in this test. The data of chromaticity was measured by TC- PⅡG auto color difference meter and its results was processed by computer. Results The value of brightness had an uptrend increase with augment of opaques thickness. Metal base color was opaqued and the basic hue was set. A lower and unstable value, besides a relative stable Y, was measured with the uncompleted opaquing. A stability of hue had been gradually concentrated within a certain range accompanying with the increase of opaquing ceramic thickness. A concentrated hue in the second thickness was found in CARAT ceramic which had high ability of opaque and had a stable hue of ceramic in comparison with other opaques. Among those changes, CARAT′s brightness showed a minimal change; a gradual stability of chromatics was presented and was limited within a certain range though the augment of opaques. Conclusion The metal color in base could be completely opaqued while opaques thickness reaches a certain range. CARAT is the materials of minimal thickness and has relatively strong capacity for opaques.
