不同全瓷冠在金铂合金基核表面颜色变化的分析

A study of colorimetric characteristics of the gold-platinum alloys substructure covered by different all-ceramic crowns before and after veneered application

目的评估金铂合金基核表面不同全瓷冠各部位的色度学参数及其与目标色片色差。方法按照全瓷冠基牙预备体要求制作金铂合金基核,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,分光光度仪分别在底冠的颈1/3、体1/3、切1/3随机取点测色。4种底冠烧结体瓷后戴入金铂基核,分光光度仪测色,以Vitapan比色板A2体瓷色片为对照,对数据进行比较。结果 4组底冠均提高基核的L*值,高于A2;a*值明显下降,低于A2;b*值较基核正负方向变化不一致。烧结体瓷后,各组L*值均下降,且低于A2。a*值和b*值均明显呈红黄色轴方向上升,各组a*值低于A2;b*值与A2接近,与A2色差减小。结论 4组全瓷冠对金属基核都有较好遮色性,但各组冠明度略低于对照A2,彩度偏绿,色差在临床可接受范围;但人眼可分辨,仍需进一步减小色差,提高颜色匹配度。

Objective To evaluate the optical data of the different sites of the gold-platinum alloys substructures covered by four different all-ceramic crowns, as well as the color difference between the crowns and target tab by using a digital dental spectrophotometer. Methods Ten gold-platinum alloy substructures were made and were respectively tested on four different groups of all-ceramic crowns（Procera aluminia, Procera zireonia, Lava zirconia, and IPS E.max glass-ceramic lithium disilicate-reinforced monolithic crown）.. The color data of the cervical, body, incisal sites of the specimens were recorded and analyzed by a spectrophotometer. The L＊, a＊, b＊ values were measured again after veneered application. The color difference between the substructures covered by all-ceramic crowns and target A2 dentine shade tab was evaluated. Results The L＊ values of the substructures can be increased by all four groups of all-ceramic copings and were higher than that of the A2 tab, but a＊ values were decreased and lower than A2 tab. The b＊ values showed inconsistent tendency of change. A statistical difference was found among four groups of copings. After veneered application, the L＊ values of all the copings declined and were lower than that of the control group. The values of a＊ and b＊ increased significantly, but thea＊ of the specimens was lower than that of the control. When compared with A2 dentine shade tab, the △E of the crowns was small, but the color difference was still clinically perceptible by human eyes. Conelusion Four ceramic crowns, made up of just coping and dentine porcelain, effectively promoted the color of the alloysubstructures, but the lightness and hue were lower than the target A2. The color difference between the specimens and target was clinically acceptable, but noticeable. Thus, veneering porcelain with lower color saturation and high translucency is needed.