应用分光光度仪比较深度变色基牙表面4种全瓷冠色度学特征

目的:采用分光光度比色仪评估深度变色ND8基底表面4种全瓷冠各部分色度学参数CIE L^*a^*b^*值及与目标色片色差。方法:制作ND8色基牙预备体,分别戴入Procera氧化铝、Procera氧化锆、Lava氧化锆、IPS E.max高度不透明压铸陶瓷底冠,分光光度仪对颈部、体部、切端测色。4组底冠经烧结A2体瓷后戴入基底(总瓷层厚度控制1.5 mm),分光光度仪同法测色,以Vitapan比色板A2体瓷色片为对照,对数据进行单因素方差分析、均数比较Bonferroni检验,计算P值。结果:4组底冠均提高基牙的L^*值,降低彩度a^*、b^*值,多数组间各部位L^*、a^*、b^*有统计学差异。烧结体瓷后,各组L^*略下降,a^*、b^*明显上升。各部分与A2色差显著减小(1.45∽3.70)。结论:4组全瓷底冠对变色基底都有较好遮色性,但各组底冠明度、彩度不一致。烧结体瓷后颜色有差异的组别减少,各组与目标色片差别在临床可接受范围。

Colorimetric Characteristics of the Dark Color Abutments Respectively Covered by Four Different All-ceramic Crowns by Using a Spectrophotometer.

Objective: To evaluate the optical data of the different sites of the dark color abutments covered by four different all-ceramic crowns and the color difference between the crowns and the target tab by using a digital dental spectrophotometer. Methods: Ten dark color(ND8) abutments were made and were respectively tried in four different groups of all-ceramic crowns (Procera aluminia, Procera zirconia, Lava zirconia, IPS E.max glass-ceramic lithium disilicate-reinforced monolithic crown).The color data of the cervical, body, incisal sites of the samples was recorded and analyzed by a spectrophotometer. The CIE L^*、a^*、b^* values were measured again after veneered. The color difference between the abutments covered by all-ceramic crowns and target A2 dentin tab was evaluated. Results: The L^* values of the abutments increased in four groups of all-ceramic copings, but a^*、b^* values were both decreased. There was statistical difference among four groups of copings. After veneered, the L^* values of all the copings declined slightly, the values of a^*, b^* increased significantly. When compared with A2 tab, the ΔE of the crowns was below 4. It meant the color difference which was almost clinically acceptable but was perceived by human eyes. Conclusion: Four ceramic copings were demonstrated to effectively promote the lightness and hue of the dark abutments. Though the colorimetric baseline of these copings was uneven, veneer porcelain which thickness less than 0.8~0.9mm could efficiently decrease the color difference to be clinically acceptable, but four ceramic systems were still different in colorimetric characteristics to some extent.