Objectives: This study aimed to investigate the accuracy of model superimposition and automatic analysis for upper and lower dentition widths in iTero Progress Assessment during the clear aligner process.
Methods: Nineteen cases were included in this retrospective case control study. Pretreatment dental cast (T0) and post treatment dental cast after staged treatment (T1) were available for three-dimensional (3D) model superimposition. The movements of maxillary teeth in the horizontal plane (cross section) after staged treatment and the widths of upper and lower dentitions were measured by 3D model superimposition in real world and iTero Progress Assessment. The data collected from the two methods were compared.
Results: The movements [Median (upper and lower quartiles)] of maxillary teeth in the horizontal plane after staged treatment were 2.31 (1.59, 3.22) and 1.79 (1.21, 3.03) mm in iTero Progress Assessment and 3D model analysis, respectively. Significant difference was observed between the two groups (P<0.05). In the measurement of upper and lower dentition width, four indicators were measured, including intercanine width upper, intermolar width upper, intercanine width lower, and intermolar width lower. Before treatment, the measurement of iTero Progress Assessment were (35.78±2.49), (56.21±2.51), (27.43±1.38), (52.26±2.91) mm, respectively, and actual measurement were (35.77±2.53), (56.17±2.47), (27.40±1.41), (52.30±2.86) mm, respectively, without significant difference (P>0.05). After stage treatment, the measurement of iTero Progress Assessment were (37.37±2.86), (57.76±2.56), (28.89±2.00), (54.16±2.19) mm, respectively, and actual measurement were (37.29±2.94), (57.71±2.63), (28.88±2.05), (54.01±2.15) mm, respectively, and there was no significant difference (P>0.05).
Conclusions: The data from iTero Progress Assessment did not coincide with the model superimposition results with palate as reference. The accuracy of model superimposition in iTero Progress Assessment needs further investigation, whereas the arch width analysis is accurate. Therefore, iTero Progress Assessment results should be interpreted with caution by orthodontists in clinical applications.
目的: 研究应用iTero软件分析无托槽隐形矫治牙齿的移动情况及牙列宽度的准确性。方法: 采用回顾性病例对照研究设计，纳入样本19例，取初诊（T0）和阶段治疗（T1）石膏模型，进行实际三维模型重叠，测量阶段治疗后上颌牙齿在水平面的移动距离和上下牙列的宽度；应用iTero软件的进展评估功能，测量同一样本阶段治疗后上颌牙齿在水平面的移动距离和上下牙列的宽度，比较二者差异。结果: 应用iTero软件进展评估功能测量的上颌牙齿水平面移动距离的中位数（上、下四分位数）为2.31（1.59，3.22）mm；实际三维模型测量上颌牙齿水平面移动距离的中位数（上、下四分位数）为1.79（1.21，3.03）mm，两组数据之间的差异具有统计学意义（P<0.05）；在上下牙列宽度测量中，测量了4个指标，包括上颌尖牙间宽度、上颌磨牙间宽度、下颌尖牙间宽度、下颌磨牙间宽度，治疗前iTero软件的进展评估功能测量结果分别为（35.78±2.49）、（56.21±2.51）、（27.43±1.38）、（52.26±2.91）mm，实际测量结果分别为（35.77±2.53）、（56.17±2.47）、（27.40±1.41）、（52.30±2.86）mm，差异无统计学意义（P>0.05）；阶段治疗后iTero软件的进展评估功能测量结果分别为（37.37±2.86）、（57.76±2.56）、（28.89±2.00）、（54.16±2.19）mm，实际测量结果分别为（37.29±2.94）、（57.71±2.63）、（28.88±2.05）、（54.01±2.15）mm，差异无统计学意义（P>0.05）。结论: iTero软件的进展评估功能测量模型重叠的准确性，与以硬腭为参考标志进行实际三维模型重叠测量的结果并不完全一致，临床医生不能完全依赖进展评估的测量结果，但其在分析牙列宽度指标方面具有较好的准确性。.
Keywords: clear aligner; model analysis; progress assessment; three-dimensional model superimposition.