不同轴面聚合度对cercon全瓷冠边缘适合性的影响研究

Effect of Different Convergence Angles on the Marginal Adaptation of Cercon Full-ceramic Crown

目的:研究不同聚合度牙体设计对cercon全瓷冠边缘适合性的影响。方法:以上颌第一磨牙为实验对象,于牙体釉牙骨质界下2mm处做标记后完全埋入自凝塑料中。将离体牙模型在牙科研磨仪上分别制备成轴面聚合度为4°、8°、12°,用肩台车针预备成90°肩台,宽约1mm,面为120°～140°。硅橡胶取离体牙印模,翻制树脂代型(日本日进齿科材料有限公司)15个,颈缘打磨光滑,分成3组,每组各5个,分别是牙体聚合度4°(4°组),牙体聚合度8°(8°组),牙体聚合度12°(12°组)。冠粘结后于体视显微镜下(总放大倍数为30)观测并记录冠的边缘间隙。结果:4°Cercon全瓷组的边缘平均间隙为(33.70±5.53)μm,8°Cercon全瓷组的边缘平均间隙为(28.90±9.55)μm,12°Cercon全瓷组的边缘平均间隙为(27.40±4.19)μm。各组间的边缘适合性存在显著差异(P<0.01)。组间两两比较采用简单相关t-检验分析,4°组与8°组间存在显著差异(P<0.05),4°组与12°组间也存在显著差异(P<0.01),而8°组与12°组之间没有显著差异。所有全瓷冠的边缘间隙均<100μm。组间两两比较采用简单相关t-检验分析,4°,8°,12°组间P<0.01,有显著差异,8°与12°组间,P>0.05无显著性差异。结论:随着牙体轴壁聚合度的增大Cercon全瓷组的边缘间隙越小即边缘适合性越好,但聚合度从8°增大到12°全瓷冠的边缘适合性改善不明显。在本实验的研究范围内可以认为8°聚合度可以提供Cercon全瓷组较好的边缘适合性。

Objective： To evaluate the effect of different con full--＇ceramic crown. Methods： The upper first molar were buried into the plastic at the level of 2ram under the convergence angles on the marginal adaptation of the Cer- teeth in vitro were used to prepare full crowns. The teeth dentino4-- enamel junction. The tooth model was prepared on the dental mill： 6^.,8^., 12~occlusal convergence angle, 90^. flat shoulder with rounded angles and the width ap- proximately lmm, the occlusion surface for 1~20^- 140^.. The impression with silica gel was made. Resin die was cart and the cervicle margin was polished. The units were randomly assigned to three groups, 51 for each, according to the convergence angle., group4^., group8^., group 12^.. The marginal gap of the crowr~ Were observed under the optical microscope （total enlargement factor was 30） and recorded , after the crowns were adhered to the die. Re- sults： The marginal gap of group 4^.was （33.70±5.53）/μm , group 8μwas （28.904±9.55）/μm, group 12^.was （27.40 ±4.19）/μm. SPSS 13.0 software was applied to analyze the result. Marginal gaps between the group 4^.and group 8^. and between the group 4^.and group 1 2^.showed a significant difference,while there was no significant difference be- tween the group 8^.and the group 12^.. All the marginal gaps were less than 100/zm. Conclusion： The marginal adap- tation wag getting better when the convergence angle increased. But there was no significant improvement after 8^.. Within the limits of this study, 8^. convergence angle provided appropriate marginal fit.