Song Won-Wook, Kim Sung-Sik, Sándor György K B, Kim Yong-Deok
Department of Oral and Maxillofacial Surgery, School of Dentistry, Pusan National University, Yangsan, South Korea.
J Oral Maxillofac Surg. 2013 Apr;71(4):752-62. doi: 10.1016/j.joms.2012.07.043. Epub 2012 Sep 23.
The purpose of this study was to investigate which factors affect upper dental midline deviation in dentofacial deformity patients using cone-beam computed tomography analysis.
Twenty-eight patients were selected for this study. Subjects were divided into 2 groups according to the amount of upper incisor (U1) midline deviation from the clinical facial midline: group 1 (U1 deviation <2 mm) and group 2 (U1 deviation >2 mm). Linear measurements, angles, and reference planes on 3-dimensional (3D) computed tomograms were obtained. The predictor variables were maxillary yaw, palatal plane angle, differences of maxillary point to the coronal and sagittal planes, and maxillary canting. The outcome variable was U1 deviation. The variables between the 2 groups and 2 sides were analyzed with a t test. Pearson correlation coefficient and multiple regression analysis were also calculated within each group for each measurement against the U1 deviation to determine which variables affect U1 deviation. P < .05 was considered statistically significant.
The patients were evenly distributed between each group (n = 14 in each group). There was significant deviation of U1 from the sagittal plane in group 2 compared with group 1 (0.99 mm in group 1 vs 1.73 mm in group 2, P < .05). When we compared yaw with the sagittal plane, group 2 was more rotated than group 1 (1.16° in group 1 vs 2.28° in group 2, P < .01). Through multiple regression analysis, the primary predictor variable for U1 deviation was maxillary yaw (P < .05).
This study suggests that maxillary yaw is the primary contributing factor for upper dental midline deviation. The use of maxillary yaw should be considered when one is performing orthognathic surgery in patients with U1 deviation to achieve optimum esthetics.
本研究旨在通过锥形束计算机断层扫描分析，探究哪些因素会影响牙颌面畸形患者的上颌牙中线偏移。
本研究选取了28例患者。根据上颌切牙（U1）中线与临床面部中线的偏移量，将受试者分为2组：第1组（U1偏移<2 mm）和第2组（U1偏移>2 mm）。在三维（3D）计算机断层扫描图像上进行线性测量、角度测量并确定参考平面。预测变量为上颌偏斜、腭平面角、上颌点与冠状面和矢状面的差异以及上颌倾斜。结果变量为U1偏移。对两组之间以及两侧的变量进行t检验。还在每组内针对每个测量值与U1偏移进行Pearson相关系数计算和多元回归分析，以确定哪些变量会影响U1偏移。P <.05被认为具有统计学意义。
患者在每组中均匀分布（每组n = 14）。与第1组相比，第2组的U1与矢状面存在显著偏移（第1组为0.99 mm，第2组为1.73 mm，P <.05）。当我们比较偏斜与矢状面时，第2组比第1组旋转得更多（第1组为1.16°，第2组为2.28°，P <.01）。通过多元回归分析，U1偏移的主要预测变量是上颌偏斜（P <.05）。
本研究表明，上颌偏斜是上颌牙中线偏移的主要影响因素。在对存在U1偏移的患者进行正颌手术时，应考虑上颌偏斜情况，以实现最佳美学效果。
