Department of Oral Biology and Engineering, Division of Oral Health Sciences, Graduate School of Biomedical Sciences, Hiroshima University, Hiroshima, Japan.
Am J Orthod Dentofacial Orthop. 2012 Jun;141(6):806-13. doi: 10.1016/j.ajodo.2011.10.027.
Orthodontic setup models are usually limited to the display of teeth, with no information about the roots. The purpose of this article is to present a method for visualizing the tooth roots in setup models by integrating information from cone-beam computed tomography and a laser scanner. The reproducibility of the integration was evaluated.
The records of 5 patients were used in this study. Three-dimensional digital models were generated from the dental casts. Tooth models were generated from the cone-beam computed tomography slices. The 3-dimensional models were superimposed on the crowns of the teeth in the tooth models and integrated. The integrated 3-dimensional tooth model and 3-dimensional setup model were registered. The reproducibility of the integration was evaluated for each tooth. Unpaired Student t tests were performed on the data between the anterior and posterior teeth, and between the right and left teeth.
The discrepancy among the integrated 3-dimensional models at the final positions after we used this technique was 0.025 ± 0.007 mm. There was a significant difference in the distance between the anterior and posterior teeth (P <0.05). However, the average distances between the anterior and posterior teeth were small: 0.023 ± 0.007 and 0.028 ± 0.007 mm, respectively. No significant difference was found between the right and left teeth (P = 0.831).
The methods presented in this study provide a reproducible visualization of tooth roots in virtual setup models by registering accurate crown models to cone-beam computed tomography scans.
正畸定位模型通常仅限于展示牙齿，而不提供有关牙根的信息。本文旨在介绍一种通过整合锥形束计算机断层扫描和激光扫描仪信息来显示定位模型中牙根的方法，并评估其整合的可重复性。
本研究使用了 5 名患者的记录。从牙模生成三维数字模型，从锥形束计算机断层扫描切片生成牙模型。将三维模型叠加到牙模型的牙冠上并进行整合。将整合的三维牙模型和三维定位模型进行配准。评估了每个牙齿的整合可重复性。对前牙和后牙、左右牙之间的数据进行了独立样本 t 检验。
使用该技术后，最终位置的整合三维模型之间的差异为 0.025 ± 0.007mm。前牙和后牙之间的距离存在显著差异（P<0.05）。然而，前牙和后牙之间的平均距离较小，分别为 0.023 ± 0.007mm 和 0.028 ± 0.007mm。左右牙之间无显著差异（P=0.831）。
本研究提出的方法通过将精确的牙冠模型与锥形束计算机断层扫描扫描进行配准，为虚拟定位模型中牙根的可视化提供了一种可重复的方法。
