关键词: 牙科全瓷, 单层结构, 双层结构, 色彩参数, 目测评价

Abstract: Objective To compare the difference in color reappearance of bilayered and monolithic molar crown fabricated with four different kinds of Dental ceramics materials. Methods Bilayered and monolithic molar crowns were fabricated with four different kinds of Dental ceramics materials for 3 different patients: IPS E. max Press, VITA in-ceram YZ zirconia, Cercon HT zirconia, Upcera ST zirconia. Color parameters of the crowns were measured with Vita Easyshade Spectrophotometer，and the color difference( △E) of crowns and contralateral teeth was calculated．The effect of color reappearance of crowns was assessed by ten color Trained examiners. Results The layers of all-ceramic restoration exhibited no influence on the mean values of L* ，a* and b* ; the kind of all-ceramic Material exhibited significant influence on the values of a* and b* ( P ＜ 0. 001) ; the interaction of layers and kinds of all-ceramic Materials showed influence on the values of a* ( P =0.040) . In terms of the visual estimation results, the monolithic crowns fabricated with VITA in-ceram zirconia, Cercon HT zirconia were not receivable while the others were. Conclusions The four studied all-ceramic bilayered crowns could achieve acceptable aesthetics ;the monolithic molar crowns fabricated with IPS E. max Press, Upcera ST zirconia could achieve acceptable aesthetics while the monolithic crowns fabricated with VITA in-ceram YZ zirconia, Cercon HT zirconia couldn’t. The clinical selection of restorative materials must be based on the transparency of all-ceramic materials and natural teeth, the distribution of color, the balance for color and intensity. On the condition that the teeth is of low opacity with monotonous color and supports the heavy loading, the monolithic restorations could be considered.

Key words: all-ceramic, bilayered, monolithic, color parameters, visual estimation