BACKGROUND Miniscrew-assisted rapid palatal expansion (MARPE) has been adopted in recent years to expand the maxilla in late adolescence and adult patients. Maxillary Skeletal Expander (MSE) is a device that exploits the principles of skeletal anchorage to transmit the expansion force directly to the maxillary bony structures and is characterized by the miniscrews' engagement of the palatal and nasal cortical bone layers. In the literature, it has been reported that the zygomatic buttress is a major constraint that hampers the lateral movement of maxilla, since maxilla is located medially to the zygomatic arches. The objective of the present study is to analyze the changes in the zygomatic bone, maxillary bone, and zygomatic arches and to localize the center of rotation for the zygomaticomaxillary complex in the horizontal plane after treatment with MSE, using high-resolution cone-beam computed tomography (CBCT) images. METHODS Fifteen subjects with a mean age of 17.2 (± 4.2) years were treated with MSE. CBCT records were taken before and after miniscrew-assisted maxillary expansion; three linear and four angular parameters were identified in the axial zygomatic section (AZS) and were compared from pre-treatment to post-treatment using the Wilcoxon signed rank test. RESULTS Anterior inter-maxillary distance increased by 2.8 mm, posterior inter-zygomatic distance by 2.4 mm, angle of the zygomatic process of the temporal bone by 1.7° and 2.1° (right and left side) (P < 0.01). Changes in posterior inter-temporal distance and zygomaticotemporal angle were negligible (P > 0.05). CONCLUSIONS In the horizontal plane, the maxillary and zygomatic bones and the whole zygomatic arch were significantly displaced in a lateral direction after treatment with MSE. The center of rotation for the zygomaticomaxillary complex was located near the proximal portion of the zygomatic process of the temporal bone, more posteriorly and more laterally than what has been reported in the literature for tooth-borne expanders. Bone bending takes place in the zygomatic process of the temporal bone during miniscrew-supported maxillary expansion.

中文翻译：

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由微植入物支持的骨骼扩张剂在水平面引起的y骨腋窝修饰，用CBCT图像分析。

背景技术近年来，微螺钉辅助快速pa扩张术（MARPE）已被采用来扩大青春期晚期和成年患者的上颌骨。上颌骨扩张器（MSE）是一种利用骨骼锚固原理将扩张力直接传递到上颌骨结构的装置，其特征在于the螺钉和鼻皮质骨层的微螺钉接合。在文献中，据报道the骨支撑是阻碍上颌骨横向运动的主要限制，因为上颌骨位于the弓的内侧。本研究的目的是分析zy骨，上颌骨，MSE治疗后，使用高分辨率的锥束计算机断层扫描（CBCT）图像，将骨弓和x弓形成旋转中心。方法用MSE治疗15名平均年龄为17.2（±4.2）岁的受试者。CBCT记录是在微螺钉辅助上颌骨扩张前后进行的。在轴向骨节（AZS）中确定了三个线性和四个角度参数，并使用Wilcoxon符号秩检验对治疗前后的参数进行了比较。结果前上颌骨间距离增加了2.8 mm，后-骨间距离增加了2.4 mm，颞骨the骨突的角度分别增加了1.7°和2.1°（左右）（P <0.01）。后颞间距离和zy颞角的变化可忽略不计（P> 0.05）。结论MSE治疗后，在水平面上，上颌骨和骨以及整个弓在横向上明显移位。zy骨-腋窝复合体的旋转中心位于颞骨the骨突的近端附近，比牙载扩张器的文献报道的更靠后和更侧向。在微螺钉支撑的上颌骨扩张过程中，颞骨的骨突发生骨弯曲。MSE治疗后，上颌骨和骨以及整个弓在横向上明显移位。zy骨-腋窝复合体的旋转中心位于颞骨the骨突的近端附近，比牙载扩张器的文献报道的更靠后和更侧向。在微螺钉支撑的上颌骨扩张过程中，颞骨的骨突发生骨弯曲。MSE治疗后，上颌骨和骨以及整个弓在横向上明显移位。zy骨-腋窝复合体的旋转中心位于颞骨the骨突的近端附近，比牙载扩张器的文献报道的更靠后和更侧向。在微螺钉支撑的上颌骨扩张过程中，颞骨的骨突发生骨弯曲。