Graduate student, Department of Prosthodontics, Peking University School and Hospital of Stomatology & National Clinical Research Center for Oral Diseases & National Engineering Laboratory for Digital and Material Technology of Stomatology & Beijing Key Laboratory of Digital Stomatology, Beijing, PR China.
Associate Professor, Department of Prosthodontics, Peking University School and Hospital of Stomatology & National Clinical Research Center for Oral Diseases & National Engineering Laboratory for Digital and Material Technology of Stomatology & Beijing Key Laboratory of Digital Stomatology, Beijing, PR China.
J Prosthet Dent. 2022 Nov;128(5):1001-1008. doi: 10.1016/j.prosdent.2021.01.029. Epub 2021 Mar 15.
The accuracy of digital scanning for complete dental arch and implant-supported complete-arch restorations has been reported. However, research addressing the accuracy of digital scanning methods for complete-arch tooth preparation is lacking.
The purpose of this in vitro study was to compare the accuracy of intraoral scanning, impression scanning, and cast scanning for complete-arch preparation.
Maxillary and mandibular jaw typodonts with 28 teeth prepared for complete crowns were used as reference casts and digitized as reference data sets with a desktop scanner. Three digital scanning methods were applied. First, the reference casts were each scanned 10 times with an intraoral scanner to generate the intraoral scanning group data sets. Second, the reference casts were each captured 10 times by using polyvinyl siloxane impression material, and the impressions were scanned with a desktop scanner to generate the impression scanning group data sets. Third, the impressions obtained in the impression scanning group were used to make gypsum casts which were then digitized with a desktop scanner to generate the cast scanning group data sets. Accuracy was determined by trueness and precision. Three-dimensional deviations of the prepared arches and anterior and posterior segments were measured from root mean square values and depicted on color-difference maps. Differences among test groups were analyzed by using a 1-way ANOVA and the post hoc Bonferroni test for normally distributed data or the Kruskal-Wallis test with Bonferroni correction for non-normally distributed data (α=.05).
The trueness of the maxillary arch was significantly higher in the impression scanning group than in the cast scanning and intraoral scanning groups (P<.05), but no significant differences were found among the 3 groups of the mandibular arch (P>.05). The precision of both arches was significantly higher in the impression scanning and intraoral scanning groups than in the cast scanning group (P<.05). Color maps showed horizontal symmetrical displacement in the intraoral scanning group relative to the reference data sets and within-group unilateral distal-end distortion. Irregular arch deformations were noted in the impression scanning group, and buccal and occlusal expansion occurred in the anterior-posterior direction in the cast scanning group. Pooled data for anterior teeth indicated that the trueness was lowest in the intraoral scanning group; however, that for the maxillary anterior teeth did not differ, while that for the mandibular anterior teeth differed significantly among groups (P<.05). For the posterior teeth, deviation was the lowest in the impression scanning group, and significant differences were noted in both arches among the 3 groups (P<.05).
Of the methods tested, impression scanning was the most accurate for the creation of a digital cast of a complete prepared arch.
已经有报道称数字扫描在完整牙弓和种植体支持的全牙弓修复中的准确性。然而，对于全牙弓牙体预备的数字扫描方法的准确性的研究还很缺乏。
本体外研究的目的是比较口内扫描、印模扫描和模型扫描在全牙弓预备中的准确性。
使用 28 颗牙制备全冠的上颌和下颌牙牙合架作为参考模型，并使用台式扫描仪对其进行数字化，作为参考数据集。应用了三种数字扫描方法。首先，使用口内扫描仪对参考模型进行 10 次扫描，生成口内扫描组数据集。其次，使用聚硅氧烷印模材料对参考模型进行 10 次采集，然后使用台式扫描仪对印模进行扫描，生成印模扫描组数据集。第三，使用印模扫描组获得的印模制作石膏模型，然后使用台式扫描仪对其进行数字化，生成模型扫描组数据集。准确性通过准确性和精密度来确定。从均方根值测量预备牙弓和前、后牙段的三维偏差，并在色差图上表示。使用单因素方差分析和事后 Bonferroni 检验（用于正态分布数据）或非参数 Kruskal-Wallis 检验和 Bonferroni 校正（用于非正态分布数据）（α=.05）分析测试组之间的差异。
上颌牙弓的准确性在印模扫描组中明显高于模型扫描组和口内扫描组（P<.05），但在下颌牙弓 3 组之间无显著差异（P>.05）。印模扫描组和口内扫描组的前、后牙弓精度均明显高于模型扫描组（P<.05）。色图显示，与参考数据集相比，口内扫描组存在水平对称的位移，且组内存在单侧远中端扭曲。在印模扫描组中观察到不规则的牙弓变形，在模型扫描组中则出现颊舌向和近远中向的扩展。前牙的汇总数据表明，准确性最低的是口内扫描组；然而，上颌前牙之间没有差异，而下颌前牙之间则有显著差异（P<.05）。对于后牙，印模扫描组的偏差最低，3 组之间在上下牙弓中均有显著差异（P<.05）。
在所测试的方法中，印模扫描是制作完整预备牙弓数字模型最准确的方法。
