The aim of the study was to assess the accuracy of commercially available software in estimating anterior tooth root inclination from digital impressions of the crowns of the teeth. Following sample size calculation and application of inclusion and exclusion criteria, 55 anterior natural teeth derived from 14 dry human skulls were selected. Impressions were taken and plaster study models were fabricated. Plaster models were scanned using the high-resolution mode of an Ortho Insight 3D laser scanner. The teeth on the digital scans were segmented and virtual roots were predicted and constructed by the Ortho Insight 3D software. The 55 natural teeth were removed from the dry skulls and scanned using the Identica extraoral white-light scanner in order to calculate their actual root angulation. The teeth were scanned twice, once to acquire the crown and the cervical part of the root, and a second time to acquire the remaining part of the root, including the apex. The two scanned segments were joined in software by superimposing them along their common part. The accuracy of the digital models generated by the Ortho Insight 3D scanner in predicting root angulation was assessed by comparing these results to the corresponding measurements of the 55 natural teeth. The long axes of the tooth models obtained from the software prediction and the scanning of the actual teeth were computed and the discrepancy between them was evaluated. The error of the methods was evaluated by repeating the measurements on 14 teeth and showed an acceptable range. The predicted tooth angulation was found to differ significantly from the actual angulation, both statistically and clinically. The angle between the predicted and actual long axes ranged from 2.0 to 37.6°(average 9.7°; median 7.4°). No statistically significant difference was found between tooth categories. Further investigations and improvements of the software are needed before it can be considered clinically effective.

中文翻译：

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通过虚拟研究模型估算前牙的牙根倾斜度：商业软件的准确性。

这项研究的目的是评估从牙冠的数字化印痕估计前牙根倾角的市售软件的准确性。在计算样本量并应用纳入和排除标准后，选择了来自14个干燥人类头骨的55颗天然前牙。留下印象并制作石膏研究模型。使用Ortho Insight 3D激光扫描仪的高分辨率模式扫描石膏模型。数字扫描上的牙齿被分割，并通过Ortho Insight 3D软件预测并构造了虚拟根。从干燥的头骨上取下55颗天然牙齿，并使用Identica口腔外白光扫描仪进行扫描，以计算其实际的牙根角度。牙齿被扫描了两次，一次采集根冠和子宫颈部分，第二次采集根部的其余部分，包括先端。通过将两个扫描段沿它们的共同部分叠加在一起，将它们连接到软件中。通过将这些结果与55个天然牙齿的相应测量值进行比较，评估了Ortho Insight 3D扫描仪生成的数字模型在预测牙根角度中的准确性。计算从软件预测和实际牙齿扫描获得的牙齿模型的长轴，并评估它们之间的差异。通过在14个牙齿上重复测量来评估方法的误差，并显示出可接受的范围。从统计学和临床​​上发现，预测的牙齿角度与实际角度有显着差异。预测长轴与实际长轴之间的角度范围为2.0至37.6°（平均9.7°；中值7.4°）。在牙齿类别之间没有发现统计学上的显着差异。在认为该软件有效之前，需要对该软件进行进一步的研究和改进。