不同桩核对Lava锆瓷冠颜色影响的实验研究

目的:研究遮色钴铬合金桩核、氧化锆桩核、纤维桩树脂核、钴铬合金金属桩核对二氧化锆全瓷冠(Lava)颜色的影响。方法:选取因牙周炎拔除的完整上颌中切牙,在釉牙骨质界冠方2.0 mm处截冠,完善根管充填治疗和桩道预备,分别制作4种不同桩核预备体各10个,每个桩核再相应制作1个Lava二氧化锆全瓷冠,内冠厚0.5 mm,饰面瓷0.7mm。采用Minolta CM一700d分光测色仪,测试4种桩核背景下Lava锆瓷冠唇面中1/3 区域L^*、a^*、b^*值,分别进行完全随机设计的单因素方差分析和两两比较的LED检验,并根据公式计算和比较色差△E。结果:4种不同桩核背景下Lava锆瓷冠的L^*、a^*、b^*值间差异有统计学意义(FL=136.206,PL=0.000;Fa= 3.454,Pa=0.026;Fb=6.172,Pb=0.000)。3组牙色桩核的色差则均不能为肉眼所识别(△E< 1.5),钴铬合金桩核组的色差超过临床可接受水平(△E>2)。结论:临床应用锆瓷冠(Lava)进行修复时(特别是前牙区),不建议使用金属桩核。

Influence of Four Kinds of Post-cores on Color of Lava All Ceramic System.

Objective: To study the influence of four kinds of post-cores on the color of Lava zirconia all ceramic system. Methods: An intact extracted maxillary central incisor was selected and excised 2mm coronal to the enamel-cementum. The tooth received endodontic treatment and root canal preparation. Four kinds of post-cores were prepared (n=10). Lava zirconia crowns were manufactured to fit the post-cores. The thicknesses of inner crown and enamel porcelain were 0.5 mm and 0.7 mm respectively. The color parameters (L^*, a^* and b^*) of the middle 1/3 of the crown were measured by the CM-700d spectrophotometry. The values of L^*, a^*, and b^* were compared by an ANOVA and a LED test, and the △E was calculated. Results: There were significant differences on the values of L^*, a^*, and b^* in four groups (P<0.05). The color difference of three teeth-color groups could not be identified by the naked eye (△E<1.5). While the △E values in the Co-Cr alloy post-cores group was beyond the clinical accepted level (△E > 2). Conclusion: The metal alloy post-core was not recommended for Lava zirconia crown, especially in the anterior area.