Yamamoto Yuri, Tanikawa Chihiro, Takada Kenji
Aust Orthod J. 2014 May;30(1):81-8.
This case report describes the management of an adult patient presenting with a skeletal Class II malocclusion with congenitally missing lower second premolars, maxillary dentoalveolar protrusion, and an excessive gingival display in full smile.
The treatment plan consisted of a combination of a segmental osteotomy to reposition the anterior part of the maxilla after upper premolar extractions and a bilateral sagittal split osteotomy (BSSO) to advance the mandible. Because the upper left permanent second molar required extraction, the upper left third molar was moved mesially during post-surgical orthodontic treatment.
After active treatment, bilateral Class I molar and canine relationships were achieved. Two years after retention, a satisfactory facial profile and dental occlusion remained with optimum overjet and overbite. Treatment also produced changes in the threedimensional (3D) configuration of the face, which was characterised by decreased labial protrusion, increased protrusion of the chin, and increased cheek prominence.
A segmental osteotomy of the anterior part of the maxilla produced favourable treatment results by reducing excessive gingival display, but also by a relative improvement in cheek prominence.
本病例报告描述了一名成年患者的治疗情况，该患者表现为骨骼Ⅱ类错牙合畸形，伴有先天性下颌第二前磨牙缺失、上颌牙槽前突以及大笑时牙龈过度外露。
治疗方案包括在上颌前磨牙拔除后行节段性截骨术以重新定位上颌前部，以及行双侧矢状劈开截骨术（BSSO）以推进下颌。由于左上恒第二磨牙需要拔除，在术后正畸治疗期间将左上第三磨牙近中移动。
积极治疗后，实现了双侧Ⅰ类磨牙和尖牙关系。保持两年后，面部轮廓和牙合关系令人满意，覆盖和覆牙合最佳。治疗还对面部的三维（3D）形态产生了改变，其特征为唇部前突减少、下巴前突增加以及脸颊突出度增加。
上颌前部的节段性截骨术通过减少牙龈过度外露以及相对改善脸颊突出度产生了良好的治疗效果。
