Cong Amalia, Massaro Camila, Ruellas Antonio Carlos de Oliveira, Barkley Mary, Yatabe Marilia, Bianchi Jonas, Ioshida Marcos, Alvarez María Antonia, Aristizabal Juan Fernando, Rey Diego, Cevidanes Lucia
Department of Orthodontics and Pediatric Dentistry, School of Dentistry, University of Michigan, Ann Arbor, MI, USA.
Department of Orthodontics, Bauru Dental School, University of São Paulo, Bauru, SP, Brazil.
Orthod Craniofac Res. 2022 Feb;25(1):64-72. doi: 10.1111/ocr.12489. Epub 2021 May 24.
Standard methods of evaluating tooth long axes are not comparable (digital dental models [DDMs], panoramic and cephalometric radiographs) or expose patients to more radiation (cone-beam computed tomography [CBCT]). This study aimed to compare angular changes in tooth long axes using DDMs vs using CBCTs.
Secondary data analysis of DDMs and CBCTs, taken before and after orthodontic treatment with piezocision of 24 patients.
Angular changes in tooth long axes were evaluated using landmarks on first molars (centre of the occlusal surface and centre of the furcation), canines and incisors (cusp tip and centre of the root at the cementoenamel junction). Wilcoxon test, intraclass correlation coefficient (ICC) and Bland-Altman plots were used to test intra- and inter-rater agreement and compare DDM and CBCT measurements.
The mesiodistal angulation and buccolingual inclination DDM measurements were reproducible. Overall mean differences between DDM and CBCT measurements of mesiodistal angulation, 1.9°±1.5°, and buccolingual inclination, 2.2 ± 2.2°, were not significant for all teeth. ICC between DDM and CBCT measurements ranged from good (0.85 molars) to excellent (0.94 canines; 0.96 incisors). The percentages of measurements outside the range of ±5 were 17.4% for molars, 13.8% for canines and 4.5% for incisors.
DDM assessment of changes in tooth long axes has good reproducibility and yields comparable measurements to those obtained from CBCT within a 5° range. These findings lay the groundwork for machine learning approaches that synthesize crown and root canal information towards planning tooth movement without the need for ionizing radiation scans.
评估牙齿长轴的标准方法不可比（数字牙科模型[DDM]、全景和头影测量X线片），或使患者接受更多辐射（锥形束计算机断层扫描[CBCT]）。本研究旨在比较使用DDM与使用CBCT时牙齿长轴的角度变化。
对24例患者进行压电切开正畸治疗前后的DDM和CBCT的二次数据分析。
使用第一磨牙（咬合面中心和根分叉中心）、尖牙和切牙（牙尖和牙骨质釉质界处的牙根中心）的标志点评估牙齿长轴的角度变化。采用Wilcoxon检验、组内相关系数（ICC）和Bland-Altman图来检验评分者内和评分者间的一致性，并比较DDM和CBCT测量结果。
DDM测量的近远中角度和颊舌倾斜度具有可重复性。所有牙齿的DDM和CBCT测量的近远中角度总体平均差异为1.9°±1.5°，颊舌倾斜度为2.2±2.2°，差异不显著。DDM和CBCT测量之间的ICC范围从良好（磨牙为0.85）到优秀（尖牙为0.94；切牙为0.96）。超出±5范围的测量百分比，磨牙为17.4%，尖牙为13.8%，切牙为4.5%。
DDM对牙齿长轴变化的评估具有良好的可重复性，并且在5°范围内产生与CBCT获得的测量结果相当的结果。这些发现为机器学习方法奠定了基础，该方法可合成冠部和根管信息以规划牙齿移动而无需进行电离辐射扫描。
