Hamdan Bin Mohammed College of Dental Medicine, Mohammed Bin Rashid University of Medicine and Health Sciences, Dubai, United Arab Emirates.
Department of Orthodontics, School of Dentistry, National and Kapodistrian University of Athens, Athens, Greece.
Prog Orthod. 2019 Nov 22;20(1):43. doi: 10.1186/s40510-019-0298-5.
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.
本研究旨在评估商用软件从牙齿冠部的数字印模估算前牙牙根倾斜度的准确性。
经过样本量计算和纳入排除标准的应用，从 14 个干燥人颅骨中选择了 55 颗前天然牙。进行印模制取，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对石膏模型进行扫描。在数字扫描上对牙齿进行分割，由 Ortho Insight 3D 软件预测和构建虚拟牙根。将 55 颗天然牙从干燥颅骨上取下，使用 Identica 口外白光扫描仪进行扫描，以计算其实际牙根角度。牙齿被扫描两次，第一次获取牙冠和牙根的颈部部分，第二次获取牙根的其余部分，包括根尖。通过在软件中将两个扫描段沿其公共部分进行叠加来连接两个扫描段。通过将 Ortho Insight 3D 扫描仪生成的数字模型预测的牙根角度与 55 颗天然牙的相应测量值进行比较，评估数字模型预测牙根角度的准确性。从软件预测和实际牙齿扫描中获得的牙齿模型的长轴被计算，并评估它们之间的差异。通过在 14 颗牙齿上重复测量来评估方法的误差，结果显示在可接受的范围内。
预测的牙齿角度与实际角度在统计学和临床方面都有显著差异。预测和实际长轴之间的夹角范围为 2.0 至 37.6°（平均 9.7°；中位数 7.4°）。不同牙齿类别之间无统计学差异。
在软件被认为具有临床有效性之前，需要进一步进行研究和改进。
