Neuromuscular and skeletal adaptations following mandibular counterclockwise rotation accompanied by intrusion of molars with Skeletal Anchorage System (SAS) in Implant-Orthodontics

骨骼锚定系统（SAS）是一种用于正畸治疗中牙齿移动的新技术。它由微型钛板组成，作为固定锚点暂时植入基底骨。虽然传统的机械治疗方法很难实现牙齿的远端和侵入，但SAS更容易实现。使用SAS时，可通过下颌逆时针旋转，并伴磨牙侵入，改善前开咬。然而，由于磨牙的侵入而改变牙齿的垂直尺寸对咀嚼肌活动和牙骨适应性的影响尚不清楚。在本文中，我们介绍了SAS的概述，并评估了SAS在种植正畸治疗前牙开放患者中产生的形态学和功能变化。治疗前后通过侧位头颅造影评估牙骨形态。对所有受试者的咬合接触面积、咬合压力、咬合力、咀嚼效率、部分咀嚼肌肉的肌电图（EMG）活动水平和下颌运动仪（MKG）的咀嚼运动进行了测量。结果与正常咬合的对照组进行比较。颅面测量显示治疗期间后牙上、下牙侵入，下颌骨逆时针旋转，前面部高度（垂直咬合尺寸）明显降低。治疗前，开放咬合患者的咀嚼效率、咬合力和咬合接触面积均明显低于对照组。患者在咬合和咀嚼时咀嚼肌活动相对较低。治疗后，咀嚼效率、咬合力和咬合接触面积均有所提高，但仍显著低于对照组。咀嚼肌协调地工作，它们的活动要高得多。本研究结果表明，在开放咬合患者中，咀嚼系统功能受损，采用SAS磨牙侵入正畸矫正可以改善形态学和功能缺陷。需要更大的样本来证实这些发现。少

The Skeletal Anchorage System (SAS) was newly developed for tooth movements in orthodontic treatment. It consists of titanium miniplates which are temporarily implanted in the basal bones as stationary anchorages. Although distalization and intrusion of teeth have been extremely difficult by traditional mechanotherapies, those are more easily achieved by SAS. With SAS, anterior open bite can be improved by the counterclockwise rotation of the mandible, accompanied by the intrusion of molars. However, it has been unknown about the influences of changing the vertical dimension by orthodontic intrusion of molars on masticatory muscle activities and dentoskeletal adaptations. In this paper, we introduced an outline of SAS and evaluated morphological and functional changes produced during the Implant-Orthodontics treatment with SAS in the anterior openbite patients. The dentoskeletal morphology was assessed through lateral cephalograms taken before and after treatment. Occlusal contact area … More , occlusal pressure, bite force, masticatory efficiency, levels of electromyogram (EMG) activity in some of the muscles of mastication, and chewing movement by mandibular kinesiograph (MKG) were measured on all subjects. The results in patients with anterior openbite were compared with those in controls with normal occlusion. Cephalometric evaluation revealed intrusion of upper and lower posterior teeth, counterclockwise rotation of the mandible and a significant decrease of anterior facial height (vertical occlusal dimension) during treatment. Before treatment, the openbite patients had masticatory efficiency, bite force and occlusal contact area significantly less than those of controls. The patients' masticatory muscle activity was relatively low during clenching and chewing. After treatment, masticatory efficiency, bite force and occlusal contact area increased, but they were still significantly lower than the control subject level. The masticatory muscles were working harmoniously, and their activity was much higher. The results of this study suggest that in openbite patients, function of the masticatory system is impaired and orthodontic correction by intrusion of molars with SAS improves both the morphological and functional deficits. A larger sample is needed to confirm these findings. Less