Ito Goshi, Koh Myongsun, Fujita Tadashi, Shirakura Maya, Ueda Hiroshi, Tanne Kazuo
Aust Orthod J. 2014 May;30(1):61-6.
If a skeletal anterior open bite malocclusion is treated by orthognathic surgery directed only at the mandible, the lower jaw is repositioned upward in a counter-clockwise rotation. However, this procedure has a high risk of relapse. In the present study, the key factors associated with post-surgical stability of corrected skeletal anterior open bite malocclusions were investigated.
Eighteen orthognathic patients were subjected to cephalometric analysis to assess the dental and skeletal changes following mandibular surgery for the correction of an anterior open bite. The patients were divided into two groups, determined by an increase or decrease in nasion-menton (N-Me) distance as a consequence of surgery. Changes in overbite, the displacements of molars and positional changes in Menton were evaluated immediately before and after surgery and after a minimum of one year post-operatively.
The group with a decreased N-Me distance exhibited a significantly greater backward positioning of the mandible. The group with an increased N-Me distance experienced significantly greater dentoalveolar extrusion of the lower molars.
A sufficient mandibular backward repositioning is an effective technique in the prevention of open bite relapse. In addition, it is important not to induce molar extrusion during post-surgical orthodontic treatment to preserve stability of the surgical open bite correction.
如果仅针对下颌骨进行正颌手术治疗骨性前牙开颌错牙合，下颌骨会逆时针向上重新定位。然而，该手术有较高的复发风险。在本研究中，对与矫正后的骨性前牙开颌错牙合术后稳定性相关的关键因素进行了调查。
对18例正颌患者进行头影测量分析，以评估下颌手术矫正前牙开颌后牙齿和骨骼的变化。患者分为两组，根据手术导致的鼻根点-颏下点（N-Me）距离增加或减少来确定。在手术前后以及术后至少一年，评估覆牙合变化、磨牙位移和颏下点的位置变化。
N-Me距离减小的组下颌骨向后定位明显更大。N-Me距离增加的组下磨牙的牙槽突明显更大。
充分的下颌骨向后重新定位是预防开颌复发的有效技术。此外，术后正畸治疗期间不引起磨牙伸长对于保持手术矫正开颌的稳定性很重要。
