Department of Orthodontics, Chonnam National University Dental Hospital, Chonnam National University, Gwangju, South Korea.
Department of Orthodontics, School of Dentistry, Chonnam National University, Gwangju, South Korea.
Am J Orthod Dentofacial Orthop. 2020 Nov;158(5):e99-e109. doi: 10.1016/j.ajodo.2020.07.032.
This research aimed to compare the estimation error of the root axis using 3-dimensional (3D) tooth models at the midtreatment stage between the whole-surface scan (WSS) and lingual-surface scan (LSS) methods.
The sample consisted of 208 teeth (26 each of central incisors, canines, second premolars, and first molars in the maxillary and mandibular dentition) from 13 patients whose pre- and midtreatment intraoral scan and cone-beam computed tomography (CBCT) were available. The 3D tooth models were constructed by merging the intraoral-scan crowns and the CBCT-scan roots obtained at the pretreatment stage. To estimate the root axis at the midtreatment stage, we superimposed the individual 3D tooth models onto the midtreatment intraoral scan obtained by the WSS and LSS methods. The midtreatment CBCT scan was used as the gold standard to determine the real root axis. The estimated root axis in terms of mesiodistal angulation and buccolingual inclination was measured in the WSS and LSS methods, and statistical analysis was performed.
The estimation errors of the mesiodistal angulation and buccolingual inclination were <2.0° in both methods. The LSS method demonstrated a statistically larger but clinically insignificant estimation error than the WSS method in the mandibular canine (mesiodistal angulation, 1.95° vs 1.62°) and the total tested teeth (mesiodistal angulation, 1.40° vs 1.29°; buccolingual inclination, 1.51° vs 1.41°).
Because the estimation errors of the root axis angle using the 3D tooth model by the WSS and LSS methods were within the clinically acceptable range, the root axis can be estimated by both methods.
本研究旨在比较在治疗中期，使用全表面扫描（WSS）和舌侧表面扫描（LSS）方法，基于三维（3D）牙模型对根轴的估计误差。
样本由 13 名患者的 208 颗牙齿（上颌和下颌牙列中每个中切牙、尖牙、第二前磨牙和第一磨牙各 26 颗）组成，这些患者的治疗前和治疗中期的口内扫描和锥形束计算机断层扫描（CBCT）均可获得。通过合并治疗前阶段获得的口内扫描牙冠和 CBCT 扫描牙根来构建 3D 牙模型。为了在治疗中期估计根轴，我们将个体 3D 牙模型叠加到通过 WSS 和 LSS 方法获得的治疗中期口内扫描上。使用治疗中期 CBCT 扫描作为确定真实根轴的金标准。在 WSS 和 LSS 方法中测量了近远中角和颊舌倾斜度的根轴估计值，并进行了统计分析。
两种方法的近远中角和颊舌倾斜度的估计误差均<2.0°。在下颌尖牙（近远中角，1.95°比 1.62°）和总测试牙齿（近远中角，1.40°比 1.29°；颊舌倾斜度，1.51°比 1.41°）中，LSS 方法的估计误差明显大于但临床上无意义的 WSS 方法。
由于 WSS 和 LSS 方法使用 3D 牙模型对根轴角度的估计误差在临床可接受范围内，因此可以使用这两种方法来估计根轴。
