In order to assess skeletal expansion, alveolar bone bending, and dental tipping after maxillary expansion, linear and angular measurements have been performed utilizing different craniofacial references. Since the expansion with midfacial skeletal expander (MSE) is archial in nature, the aim of this paper is to quantify the differential components of MSE expansion by calculating the fulcrum locations and applying a novel angular measurement system. Thirty-nine subjects with a mean age of 18.2 ± 4.2 years were treated with MSE. Pre- and post-expansion CBCT records were superimposed and compared. The rotational fulcrum of the zygomaticomaxillary complex was identified by localizing the interfrontal distance and modified interfrontal distance. Based on the fulcrum, a novel angular measurement method is presented and compared with a conventional linear method to assess changes of the zygomaticomaxillary complex, dentoalveolar bone, and maxillary first molars. From 39 patients, 20 subjects have the rotational fulcrum of the zygomaticomaxillary complex at the most distant points of the interfrontal distance (101.6 ± 4.7 mm) and 19 subjects at the most distant points of the modified interfrontal distance (98.9 ± 5.7 mm). Linear measurements accounted for 60.16% and 56.83% of skeletal expansion, 16.15% and 16.55% of alveolar bone bending, and 23.69% and 26.62% of dental tipping for right and left side. Angular measurements showed 96.58% and 95.44% of skeletal expansion, 0.34% and 0.33% alveolar bone bending, and 3.08% and 4.23% of dental tipping for the right and left sides. The frontozygomatic, frontoalveolar, and frontodental angles were not significant different (P > 0.05). In the coronal plane, the center of rotation for the zygomaticomaxillary complex was located at the most external and inferior point of the zygomatic process of the frontal bone or slightly above and parallel to the interfrontal distance. Due to the rotational displacement of the zygomaticomaxillary complex, angular measurements should be a preferred method for assessing the expansion effects, instead of the traditional linear measurement method.

中文翻译：

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利用支点的新型角度测量，对微植入物支持的中颌骨扩张器（MSE）诱导的骨骼，牙槽和牙齿成分进行差异评估。

为了评估上颌骨扩展后的骨骼扩展，牙槽骨弯曲和牙齿倾斜，已使用不同的颅面参考进行了线性和角度测量。由于中颌骨扩张器（MSE）的扩张本质上是拱形的，因此本文的目的是通过计算支点位置并应用新型的角度测量系统来量化MSE扩张的微分分量。MSE治疗了39名平均年龄为18.2±4.2岁的受试者。扩展前和扩展后的CBCT记录进行了叠加和比较。izing骨-腋窝复合体的旋转支点是通过定位额叶间距离和修改的额叶间距离来确定的。根据支点，提出了一种新颖的角度测量方法，并将其与常规线性方法进行了比较，以评估突腋复合体，牙槽骨和上颌第一磨牙的变化。在39例患者中，有20名受试者在额间距离最远点（101.6±4.7 mm）处有go骨-腋窝复合体的旋转支点，在改良额额间距离（98.9±5.7 mm）的最远点处有19名受试者。线性测量分别占骨骼扩张的60.16％和56.83％，牙槽骨弯曲的16.15％和16.55％，以及左右两侧的小费的23.69％和26.62％。角度测量显示右侧和左侧的骨骼扩张分别为96.58％和95.44％，牙槽骨弯曲为0.34％和0.33％，以及牙尖的3.08％和4.23％。额oz，额肺泡，与前牙角无显着性差异（P> 0.05）。在冠状平面中，骨-腋窝复合体的旋转中心位于额骨the骨突的最外部和最下方，或者稍高于并平行于额骨间距离。由于zy骨-腋窝复合体的旋转位移，角度测量应该是评估扩展效果的首选方法，而不是传统的线性测量方法。