骨下颌前突术前正畸去代偿治疗效果的研究

目的：探讨术前去代偿性在骨性下颌前突畸形矫治中的应用。方法：18例已接受过正畸－外科联合治疗的骨性下颌前突患者，以X线头影测量方法对其术前正畸去代偿的前后结果进行研究。结果：在骨性下颌前突患者，普遍存在牙齿的代偿现象，牙代偿不仅存在于下颌，而且存在于上颌；并同时存在于前牙和后牙；去代偿后，上、下牙齿相对于基骨的位置得到了明显的改善。结论：术前去代偿为外科手术后退下颌骨至正常位置打下良好的基础。术前正畸法代偿，是治疗骨性下颌前突畸形的重要步骤。也是获得高质量手术结果的可靠保证。     

外科—正畸联合矫治骨性下颌前突

为探讨正畸治疗处外科手术在矫治骨性下颌前突中的作用相互关系，作者对１５９例患者的治疗计划及矫治结果进行分析，总结出正畸治疗在外科－正畸联合矫治下颌前突中的作用。     

外科－正畸联合矫治骨性下颌前突

为探讨正畸治疗和外科手术在矫治骨性下颌前突中的作用及相互关系，作者对１５９例患者的治疗计划及矫治结果进行分析，总结出正畸治疗在外科－正畸联合矫治下颌前突中的作用。主要包括：去除前牙代偿、排齐牙列、调整牙弓的相容性、调整关系、保持的稳定性，并强调去代偿是术前正畸治疗的主要目的。术前正畸治疗与后退下颌骨或（和）骨段的外科术式的选择之间有着密切关系，下颌体部截骨和升支部垂直截骨构成了经术前正畸准备后矫治下颌骨前突的主要外科术式。     

骨性下颌前突伴偏斜畸形的牙弓和牙齿代偿分析

目的：作者对骨性下颌前突伴偏斜患者的牙弓和牙齿代偿现象进行研究。方法：测量11例骨性下颌前突伴偏斜患者治疗前模型，将上颌腭中缝作为中线标准，测量牙弓两侧同名牙接触点到腭中缝的距离，观测牙弓的对称性。同时He平面作为参考平面，测量上下颌后牙颊舌向倾斜程度。结果：骨性下颌前突伴偏斜患者的上牙弓左右不对称,偏斜侧（下颌颏部所指向的一侧）牙弓宽度明显大于对侧。偏斜侧上后牙颊向倾斜， ．下后牙舌向倾斜。结论：下颌前突伴偏斜形会导致上颌牙弓和上下颌后牙出现代偿，在术前矫治的重点是去代偿治疗。     

下颌前突外科手术前后的正畸治疗

目的 总结、分析口腔正畸－正颌外科联合矫治下颌前突畸形的治疗经验,以指导临床工作。方法 对４０例年龄为１７￣３８岁的下颌前突患者经口腔正畸与正颌外科联合矫治的资料进行分析。结果 ４０例下颌前突患者平均术前正畸治疗时间９个月（２￣２５个月）,术后正畸治疗时间７．６个月（２￣１５个月）。整个治疗过程平均１６个月（４￣２５个月）。术前正畸治疗的目标为排齐上下牙列,完成切牙和磨牙的去代偿治疗,整平牙例,协     

骨性下颌前突正畸—正颌联合治疗前后髁突位置变化的研究

目的:研究骨性下颌前突正畸-正颌联合治疗前后髁突位置的变化,探讨下颌双侧升支矢状劈开后退术对于治疗骨性下颌前突的可靠性和安全性。方法:15例骨性下颌前突的安氏Ⅲ类错牙合畸形病人,行下颌双侧升支矢状劈开后退术(bilateral sagittal split ramus osteotomy,BSSRO)与正畸矫治联合治疗,分别在术前两周和术后半年拍摄许勒式X线片,测量BSSRO术前、术后双侧髁突在关节窝内前、后、上间隙的距离,进行统计学分析比较术前术后髁突位置的变化情况。结果:15例病例经BSSRO配合正畸治疗后均达到正常的咬合关系,恢复了口腔功能,改善了面部容貌;正颌术前:左侧关节前、后、上间隙均数为1.91、2.30、2.51 mm;右侧前、后、上间隙均数为2.14、2.65、2.98 mm;正颌术后:左侧关节前、后、上间隙均数为1.99、2.38、2.62 mm;右侧前、后、上间隙均数为2.14、2.66、2.60 mm。术后半年双侧髁突在关节窝内的上、前、后间隙与术前两周相比,差异均无统计学意义。结论:下颌双侧升支矢状劈开后退术(BSSRO)配合正畸治疗,能够安全有效的矫治骨性下颌前突,并且未使其出现新的关节症状。     

下颌前突综合征的术前及术后正畸治疗

<正> 下颌前突综合征是成人牙颌面畸形中比较多见(约占40％)、而且严重的一种类型,主要表现为下颌及颏部前突,上颌后缩,面下部过长,多数牙反(牙合)。这类患者单纯手术,其术后咬合关系常不理想,影响咬合功能,且容易复发,术前及术后正畸常常是必不可少的过程。作者近几年来进行该类患者术前及术后矫治11例,收     

成人严重骨性Ⅲ类错牙合术前正畸及手术设计

提要：骨性Ⅲ类错牙合的正畸-正颌联合治疗是临床中比较复杂的情况之一。正畸-正颌联合治疗一般包括术前正畸、正颌手术及术后正畸3个阶段：排齐上下牙列,去除牙代偿,协调上下颌牙弓;采用颏成形术、单颌或双颌手术后退下颌骨或（和）前移上颌骨,改善侧貌美观;术后精细调整,形成良好咬合关系。治疗应根据患者颌骨畸形的严重程度、上下唇形态、颏部位置、牙列拥挤度、牙齿倾斜度等畸形特征,具体分析,严格把握适应证,对于边缘病例尤应重视。矫治过程中,应重视术前正畸和手术设计,为正颌手术提供便利。     

现代正颌外科与口腔正畸

寻求正颌外科治疗的牙颌面畸形患者 ,不仅伴有明显的上下颌骨位置异常 ,也必然伴有咬合关系异常 ,例如牙齿排列、牙弓关系、牙轴方向、Spee曲线异常等。尽管正颌外科手术可以矫正异常的颌骨位置关系 ,改善咬合关系 ,甚至通过多个区域的分块截骨调整异常的曲线和牙轴方向等 ,但要达到满意的咬合关系重建 ,缺少口腔正畸医生的参与 ,不经过术前术后的正畸治疗却是无法达到的。以往 ,医生们关注更多的是牙颌面畸形患者容貌的变化 ,而忽略了患者的咬合关系。颌面外科医生更加侧重手术技巧 ,总是以颌骨截除量和骨骼畸形改变的大小以及软组织侧…     

26例下颌前突畸形外科矫正的临床分析

作者对26例下颌前突畸形患者进行了手术矫正，其中18例行双侧SSRO术，8例采用下颌骨体部截骨术后退下颌骨，正畸保持疗效。除3例复发外，皆达设计要求。作者分析讨论了：1．术中、术后并发症产生及处理。认为只要操作处理得当，大部分并发症皆可避免。2．手术与颞下颌关节病症的联系及手术前后X线片结构改变对比。61％的患者因异常关系有不同程度的关节症状。术后35％症状消失，26％无变化。关节X线片术前后对比无明显结构异常变化。3．引起术后复发的原因：3例患者复发的原因主要为术前设计错误及未能坚持术前、术后正畸治疗所致。     

Extraoral and intraoral vertical subcondylar ramusosteotomy for correction of mandibular prognathism

Vertical subcondylar ramusosteotomy for correction of mandibular prognathism was performed in 203 cases with an extraoral (EVSO) and in 55 cases with an intraoral (IVSO) approach. Clinical and surgical observations were analyzed and the 2 techniques compared with regard to operation time, per- and postoperative complications, postoperative morbidity of the patients and the duration of hospital stay. The extraoral approach demonstrated significantly shorter operation time, less blood loss and shorter hospital stay. The extent of postoperative swelling, nausea and vomiting was also in favour of the EVSO. Serious complications were few, and both techniques were considered as satisfactory and safe.     

Three-dimensional condylar displacement and remodelling following correction of asymmetric mandibular prognathism with maxillary canting

The aim of this study was to investigate the three-dimensional condylar displacement and long-term remodelling following the correction of asymmetric mandibular prognathism with maxillary canting. Thirty consecutive patients (60 condyles) with asymmetric mandibular prognathism >4 mm and occlusal canting >3 mm, treated by Le Fort I osteotomy and bilateral sagittal split ramus osteotomy, were included. Spiral computed tomography scans obtained at different periods during long-term follow-up (mean 17 ± 7.2 months) were gathered and processed using ITK-SNAP and 3D Slicer. The condyles were subjected to translational and rotational displacements immediately after the surgery (T2), which had not fully returned to the original preoperative positions at the last follow-up (T3). Condylar remodelling was observed at the last follow-up (T3), with the shorter side condyles subjected to higher surface resorption and overall condylar volume loss. The overall condylar volume on the shorter side was significantly reduced compared to the volume on the elongated side (?11.9 ± 90.6 vs ?131.7 ± 138.2 mm³; P = 0.001). About 73%, 87%, 53%, and 54% of the shorter side condyles experienced resorption on the posterior, superior, medial, and lateral surfaces, respectively; in contrast, only 50% of the elongated side condyles showed resorption on the superior surface. Higher preoperative asymmetry was significantly correlated with increased postoperative condylar displacement (P < 0.05). The vertical asymmetry and the vector of condylar displacement were associated with the resultant remodelling process. It is concluded that condylar resorption of the shorter side condyle, which may affect the long-term surgical stability, has to be considered.     

Extraoral vertical ramus osteotomy combined with internal fixation for the treatment of mandibular deformities

Extraoral vertical ramus osteotomy (EVRO) is used in orthognathic surgery for the treatment of mandibular deformities. Originally, EVRO required postoperative intermaxillary fixation (IMF). EVRO has been developed using rigid fixation, omitting postoperative IMF. We examined retrospectively the long-term stability and postoperative complications for patients with mandibular deformities who underwent EVRO with internal rigid fixation. Patients who were treated with EVRO for a mandibular deformity in the period 2008–2017 at the Clinic of Oral and Maxillofacial Surgery, Mölndal, Sweden were included (N = 26). Overjet and overbite were calculated digitally and cephalometric analyses were performed preoperatively, and at three days, six months, and 18 months postoperatively. There was a general setback of the mandible, decreased gonial angle and reduced degree of skeletal opening. Excellent dental and vertical skeletal stabilities were seen up to 18 months postoperatively, although relapse was seen sagitally up to six months postoperatively. Since the overjet did not show any significant change over time, the sagittal skeletal changes have been attributed to dental compensation. There was no permanent damage to the facial nerve and 5.8% neurosensory damage to the inferior alveolar nerve was observed.     

Physiological positioning strategy alters condylar position after mandibular ramus sagittal split osteotomies for mandibular prognathism

Objective: The aim of this study was to elucidate the physiological position of the proximal segment for postoperative jaw movement in patients with mandibular prognathism.

Methods: Twenty-two patients with mandibular prognathism were treated by orthognathic surgery using bilateral mandibular sagittal split ramus osteotomies (SSRO) with a physiological positioning strategy. The skeletal stability was assessed, and the movement of the proximal segment was evaluated by cephalography and computed tomography performed preoperatively, immediately postoperatively, and one year postoperatively.

Results: The patients were divided into two groups: the stable group (SNB relapse <1.5°) and the relapse group (SNB relapse ≥1.5°). In the stable group at one year postoperatively, the average SNB relapse was only 0.29° (7%), the condylar head had moved posteriorly by 0.75 mm, and the proximal segment had rotated counterclockwise by 1.2°.

Conclusion: This new physiological positioning strategy improves the position of the condyle compared with the preoperative position in patients with mandibular prognathism.     

Surgical morbidities of sagittal split ramus osteotomy versus intraoral vertical ramus osteotomy for the correction of mandibular prognathism: a randomized clinical trial

The sagittal split ramus osteotomy (SSRO) and intraoral vertical ramus osteotomy (IVRO) are two common orthognathic procedures for the treatment of mandibular prognathism. This randomized clinical trial compared the surgical morbidities between SSRO and IVRO for patients with mandibular prognathism over the first 2 years postoperative. Ninety-eight patients (40 male, 58 female) with a mean age of 24.4 ± 3.5 years underwent bilateral SSRO (98 sides) or IVRO (98 sides) as part or all of their orthognathic surgery. IVRO presented less short-term and long-term surgical morbidity in general. The SSRO group had a greater incidence of inferior alveolar nerve deficit at all follow-up time points (P <  0.01). There was more TMJ pain at 6 weeks (P =  0.047) and 3 months (P =  0.001) postoperative in the SSRO group. The SSRO group also presented more minor complications, which were related to titanium plate exposure and infection. There were no major complications for either technique in this study. Despite the need for intermaxillary fixation, IVRO appears to be associated with less surgical morbidity than SSRO when performed as a mandibular setback procedure to treat mandibular prognathism.     

Reduction genioplasty enhances quality of life in female patients with prognathism and maxillary hypoplasia undergoing bimaxillary osteotomy

The structure of the chin determines facial attractiveness and is directly linked to quality of life (QoL). In patients with prognathism and maxillary hypoplasia, bimaxillary osteotomy (BIMAX) with mandibular setback does not always lead to a more slender chin or improved aesthetics. The aim of the present study was to evaluate whether QoL differed between females undergoing BIMAX alone (group I; n = 30) and those undergoing BIMAX combined with reduction genioplasty (group II; n = 30). Presurgical and postsurgical evaluations included cephalography, photogrammetry, and the Oral Health Impact Profile with one additional domain (aesthetics). Setback of the hard tissue pogonion was significantly greater (P = 0.006) in group II (7.1 mm) than in group I (2.7 mm). Only in group II were soft tissue pogonion changes highly significant (P < 0.001), amounting to a mean of 5 mm. In both groups, the QoL domains ‘social disability’, ‘psychological discomfort’, and ‘dissatisfied with aesthetics’ changed significantly towards lower impact scores. Changes in the latter two domains were significantly greater in group II patients than in group I patients (P = 0.021; P < 0.001) and were correlated with changes in the soft tissue pogonion in the horizontal (P = 0.024; P = 0.022) and vertical directions (P = 0.037; P = 0.042). Genioplasty addresses both psychological and aesthetic concerns, and therefore significantly enhances postsurgical QoL.     

The main occluding area in normal occlusion and mandibular prognathism

Objective:To clarify whether the concept of main occluding area, where hard food is initially crushed, exists in patients who have a jaw deformity.Materials and Methods:Nineteen subjects with normal occlusion, 18 patients with mandibular prognathism, and 11 patients with mandibular prognathism who had undergone orthognathic surgery participated in this study. The main occluding area was identified by clenching Temporary Stopping. The coincidence, location of the main occluding area, and distance from the first molars to main occluding area were examined.Results:High coincidence of the main occluding area was obtained in all groups, signifying that the main occluding area exists even in these patients. Mandibular main occluding area was located on the first molar in all groups. Maxillary main occluding area in subjects with normal occlusion was located on the first molar. However, it was located on the second premolar and first molar in patients with mandibular prognathism, and on the first and second molars in patients with mandibular prognathism who had undergone orthognathic surgery. There was a statistically significant difference in distance from the maxillary first molar to the main occluding area among groups, but there was no difference in the distance from the mandibular first molar among groups.Conclusion:The main occluding area is more stable on the mandibular first molar than the maxilla in all groups.     

Bone availability for mandibular molar distalization in adults with mandibular prognathism

Objectives:To investigate the retromolar space available for molar distalization in patients with mandibular prognathism.Materials and Methods:Using cone-beam computed tomography, the posterior mandibular dimensions in 110 consecutive patients with Class I or Class III malocclusion were measured (mean age, 27.0 ± 7.1 years). The shortest linear distances from the distal root of the right mandibular second molar to the inner border of the mandibular cortex were measured at the level of root furcation and 2, 4, and 6 mm apical to the furcation along the sagittal line and the posterior line of occlusion. The retromolar distances were compared between the Class I and Class III malocclusion groups using general linear mixed models.Results:The retromolar space measured through the sagittal line showed no significant intergroup difference. Among the distances measured through the posterior line of occlusion, the space measured at depths 0 and 2 mm to the furcation were significantly greater in the Class III group than in the Class I group.Conclusions:Patients with Class III malocclusion have greater retromolar space for mandibular molar distalization along the posterior line of occlusion only at the level of the second molar furcation.