Lee Yun-Sik, Suh Hee-Yeon, Lee Shin-Jae, Donatelli Richard E
Postgraduate student, Department of Orthodontics, School of Dentistry and Dental Research Institute, Seoul National University, Seoul, Korea.
Professor and chair, Department of Orthodontics, School of Dentistry and Dental Research Institute, Seoul National University, Seoul, Korea.
Am J Orthod Dentofacial Orthop. 2014 Dec;146(6):724-33. doi: 10.1016/j.ajodo.2014.08.010.
The use of bimaxillary surgeries to treat Class III malocclusions makes the results of the surgeries more complicated to estimate accurately. Therefore, our objective was to develop an accurate soft-tissue prediction model that can be universally applied to Class III surgical-orthodontic patients regardless of the type of surgical correction: maxillary or mandibular surgery with or without genioplasty.
The subjects of this study consisted of 204 mandibular setback patients who had undergone the combined surgical-orthodontic correction of severe skeletal Class III malocclusions. Among them, 133 patients had maxillary surgeries, and 81 patients received genioplasties. The prediction model included 226 independent and 64 dependent variables. Two prediction methods, the conventional ordinary least squares method and the partial least squares (PLS) method, were compared. When evaluating the prediction methods, the actual surgical outcome was the gold standard. After fitting the equations, test errors were calculated in absolute values and root mean square values through the leave-1-out cross-validation method.
The validation result demonstrated that the multivariate PLS prediction model with 30 orthogonal components showed the best prediction quality among others. With the PLS method, the pattern of prediction errors between 1-jaw and 2-jaw surgeries did not show a significantly difference.
The multivariate PLS prediction model based on about 30 latent variables might provide an improved algorithm in predicting surgical outcomes after 1-jaw and 2-jaw surgical corrections for Class III patients.
使用双颌手术治疗III类错牙合畸形会使手术结果更难以准确评估。因此，我们的目标是开发一种准确的软组织预测模型，该模型可普遍应用于III类外科正畸患者，而不论手术矫正类型如何：上颌或下颌手术，有无颏成形术。
本研究的受试者包括204例接受严重骨骼III类错牙合畸形联合外科正畸矫正的下颌后缩患者。其中，133例患者接受了上颌手术，81例患者接受了颏成形术。预测模型包括226个自变量和64个因变量。比较了两种预测方法，即传统的普通最小二乘法和偏最小二乘法（PLS）。在评估预测方法时，实际手术结果为金标准。拟合方程后，通过留一法交叉验证法计算绝对值和均方根值的测试误差。
验证结果表明，具有30个正交分量的多元PLS预测模型在其他模型中显示出最佳的预测质量。使用PLS方法，单颌手术和双颌手术之间的预测误差模式没有显著差异。
基于约30个潜在变量的多元PLS预测模型可能为预测III类患者单颌和双颌手术矫正后的手术结果提供一种改进的算法。
