利用数字化印模和软件分析上中切牙全瓷冠牙体预备的精度

Analysis of the precision of tooth preparation of all-ceramic crown on maxillary central incisor by digital impression and software

目的利用数字化印模和设计软件对不同工作年限医师预备的上中切牙全瓷冠牙体预备的精度进行分析和评估。方法在实验用标准牙模上,3组实验对象(上海第九人民医院口腔修复医师组、临床型研究生组和临床前本科生组)按照统一的牙体预备程序和标准,对右侧上颌中切牙进行全瓷冠牙体预备,利用Planscan口内扫描仪获取标准预备体和各实验组的样本数据,量化牙体预备各评价指标,并利用评分软件比较各组样本与标准预备体、各组样本之间的肩台宽度、聚合度以及轴壁高度。采用统计学单因素方差分析及最小显著性差异法(Least significant difference,LSD)多重比较的方法,分析不同分组之间的差异。结果在肩台宽度与轴壁高度方面,临床经验不尽相同的3组在统计学上显示差异有显著性意义(P<0.05)。结论在临床前牙体预备训练中应注意轴壁高度不过度预备,尤其应着重控制肩台宽度预备量的训练。

Objective Using CAD/CAM to analyze the precision of tooth preparation of maxillary central incisor all-ceramic crowns performed by students and dentists. Methods According to the unifed tooth prepara-tion procedure and standard, three groups of operators （prosthodontics, clinical postgraduates and preclinical un-dergraduates from Shanghai Ninth People Hospital）prepared right upper central incisor for all-ceramic crown on tooth model.The data of standard preparation and samples was obtained, the evaluation indicators of tooth prepara-tion was quantifed by Planscan, and the shoulder width, axial wall height and taper angle of samples with standard preparation were compared by digital software. Differences of three groups were analyzed by one-way analysis of variance and LSD（least signifcant difference）. Results There was signifcantly statistical difference among three groups in shoulder width（P〈0.05）and axial wall height （P〈0.05）Conclusion Appropriate preparation of axial wall height and shoulder width should get more attention in preclinical training.【