Stability after surgical-orthodontic corrective of skeletal Class III malocclusion. 3. Combined maxillary and mandibular procedures

Stability after combined Le Fort I and bilateral sagittal split osteotomies was reviewed in 51 patients with skeletal Class III malocclusion. Because vertical changes in the position of the maxilla affect both the vertical and anteroposterior positions of the mandible, the sample was subdivided by the direction of vertical movement of the maxilla at surgery. Excellent postsurgical stability was observed in the long-face Class III patients in whom upward and forward movement of the maxilla was combined with ramus osteotomy to prevent excessive forward rotation of the mandible. When the maxilla was moved forward and the mandible set back with minimal vertical change, moderate relapse tendencies were observed in both jaws, but most of the correction was maintained at 1 year. When the maxilla was moved down and forward while the mandible was set back, moderate vertical relapse of the maxilla and anteroposterior relapse of the mandible followed. Stability of the downward movement of the maxilla was, on average, better than that resulting from maxillary surgery alone.     

Stability of skeletal Class III malocclusion after combined maxillary and mandibular procedures: titanium versus resorbable plates and screws for maxillary fixation.

PURPOSE: The aim of this study was to evaluate skeletal stability after double jaw surgery for correction of skeletal Class III malocclusion to assess if there were any differences between resorbable plate and screws and titanium rigid fixation of the maxilla. PATIENTS AND METHODS: Twenty-two Class III patients had bilateral sagittal split osteotomy for mandibular setback stabilized with rigid internal fixation. Low level Le Fort I osteotomy for maxillary advancement was stabilized with conventional titanium plate and screws in 12 patients (group 1) and with resorbable plate and screws in 10 patients (group 2). Lateral cephalograms were taken before surgery, immediately postoperatively, 8 weeks after surgery, and 1 year postoperatively. RESULTS: Before surgery both groups were balanced with respect to linear and angular measurements of craniofacial morphology. One year after surgery, maxillary stability was excellent in both groups. In group 1 no significant correlations were found between maxillary advancement and relapse. In group 2, significant correlations were found between maxillary advancement and relapse at A point and posterior nasal spine. No significant differences in postoperative skeletal and dental stability between groups were observed. CONCLUSION: Surgical correction of Class III malocclusion after combined maxillary and mandibular procedures appears to be a fairly stable procedure for maxillary advancements up to 5 mm independently from the type of fixation used to stabilize the maxilla. Resorbable devices should be used with caution for bony movements of greater magnitude until their usefulness is evaluated in studies with large maxillary advancements.     

Stability of skeletal class III malocclusion after combined maxillary and mandibular procedures: rigid internal fixation versus wire osteosynthesis of the mandible.

PURPOSE: The aim of this study was to evaluate skeletal stability after double-jaw surgery for correction of skeletal Class III malocclusion to assess whether there were any differences between wire and rigid fixation of the mandible. PATIENTS AND METHODS: Thirty-seven Class III patients had Le Fort I osteotomy stabilized with plate and screws for maxillary advancement. Bilateral sagittal split osteotomy for mandibular setback was stabilized with wire osteosynthesis and maxillomandibular fixation for 6 weeks in 20 patients (group 1) and with rigid internal fixation in 17 patients (group 2). Lateral cephalograms were taken before surgery, immediately after surgery, 8 weeks after surgery, and 1 year after surgery. RESULTS: Before surgery, both groups were balanced with respect to linear and angular measurements of craniofacial morphology. One year after surgery, maxillary sagittal stability was excellent in both groups, and bilateral sagittal split osteotomy accounted for most of the total horizontal relapse observed. In group 1, significant correlations were found between maxillary advancement and relapse at the posterior maxilla and between mandibular setback and postoperative counterclockwise rotation of the ramus and mandibular relapse. In group 2, significant correlations were found between mandibular setback and intraoperative clockwise rotation of the ramus and between mandibular setback and postoperative counterclockwise rotation of the ramus and mandibular relapse. No significant differences in postoperative skeletal and dental stability between groups were observed except for maxillary posterior vertical position. CONCLUSIONS: Surgical correction of Class III malocclusion after combined maxillary and mandibular procedures appears to be a fairly stable procedure independent of the type of fixation used to stabilize the mandible.     

Stability of maxillary advancement for correction of skeletal Class III malocclusion after combined maxillary and mandibular procedures: preliminary results of an active control equivalence trial for semirigid and rigid fixation of the maxilla

In this paper preliminary results are presented of a prospective study designed to examine the effect of maxillary fixation methods on postoperative stability. The purpose of this study was to evaluate the stability of Le Fort I osteotomy stabilized with semirigid fixation of the maxilla (SRMF) or rigid fixation of the maxilla (RMF). All patients had skeletal Class III malocclusion and underwent bimaxillary surgery (Le Fort I maxillary advancement with or without superior repositioning and bilateral sagittal split osteotomies of the mandible). Standardized cephalometric analysis was performed on serial radiographs of 42 patients immediately before surgery, 1 week after surgery, after release of fixation, and 1 year postoperatively. The patients were randomized into 2 treatment groups: 23 patients received RMF (group A), and 19 patients received SRMF (group B). Within the groups, patients showed good stability with regard to their baseline characteristics. To show the therapeutic equivalence of the 2 treatments, analysis of the recorded data followed the approach for an equivalence trial. The mean surgical advancement was 5.34 +/- 1.50 mm for group A and 4.51 +/- 1.37 mm for group B. The mean amount of postsurgical relapse was 0.98 +/- 1.27 mm for group A and 0.30 +/- 1.04 mm for group B. Group A patients experienced 93% of their relapse (0.92 mm) during fixation, while group B patients experienced 96% of their relapse (0.29 mm) after release of fixation. RMF provided better stability than SRMF for all maxillary landmarks in the vertical plane. All considered points both in horizontal and vertical plane exhibited full equivalence for 95% confidence intervals, which seems to indicate equivalent stability between the surgical procedures.     

口外前牵引联合颏兜矫治AngleⅢ骨性反牙8例报告

目的总结应用口外前牵引联合颏兜矫治混合牙列期和恒牙早期安氏III类骨性反牙合的效果.方法7-12岁安氏Ⅲ类骨性的反牙合8例,用口外前牵引联合颏兜矫治.结果 上颌骨与上牙弓均有前移,上颌长度增加,A点前移,上切牙唇倾度减小;下切牙舌侧倾斜;上下颌骨矢状关系逐渐趋向正常,凹面型得到改善.结论口外前牵引联合颏兜是矫治混合牙列期和恒牙早期安氏III类骨性反牙的有效方法.     

前方牵引对早期前牙反(牙合)患者软组织侧貌的影响

目的:探讨前方牵引矫治对早期前牙反软组织侧貌的影响。方法:选择前牙反伴有颜面形态异常(审美线明显异常)的儿童60人,男27人,女33人,年龄范围8～11岁,平均年龄9.3岁,将样本随机分为对照组和前方牵引治疗组,观察及治疗周期为11～13个月,平均12.1个月。治疗前后分别拍摄头颅侧位X线片,进行头影测量分析,统计学分析采用配对t检验。结果:治疗组矫治后的面突角、全面突角、下唇基角及鼻唇角明显减小,上下唇基角明显增大,上唇突点到审美线距离明显改善,与对照组间的差异均呈高度显著性,而上唇基角及下唇突点到审美线的距离治疗前后无明显变化。结论:前方牵引矫治后面部软组织侧貌明显改善,凹面型变为直面型或者接近正常面型,鼻、上唇、下唇以及颏部四者间的关系趋于协调,唇部曲线变得平缓、协调。     

Stability after surgical-orthodontic correction of skeletal Class III malocclusion. I. Mandibular setback

Postsurgical stability of mandibular setback to correct mandibular prognathism was compared for three approaches: transoral vertical ramus osteotomy, bilateral sagittal split osteotomy with wire osteosynthesis and maxillomandibular fixation, and bilateral sagittal split osteotomy with rigid internal fixation via bone screws. In the transoral vertical ramus osteotomy group, the mean postsurgical change in chin position was almost zero, but nearly 50% of the patients did have clinically significant changes in chin position; two thirds of these movements were posterior and one third anterior. In the bilateral sagittal split osteotomy groups, the chin either stayed in its immediately postsurgical position or moved anteriorly. In one fourth of the patients who received maxillomandibular fixation and in nearly half of the patients who received rigid internal fixation, the chin moved forward more than 4 mm.     

Three-dimensional evaluation of soft tissue change gradients after mandibular setback surgery in skeletal Class III malocclusion

Objective:To evaluate whether mandibular setback surgery (MSS) for Class III patients would produce gradients of three-dimensional (3D) soft tissue changes in the vertical and transverse aspects.Materials and Methods:The samples consisted of 26 Class III patients treated with MSS using bilateral sagittal split ramus osteotomy. Lateral cephalograms and 3D facial scan images were taken before and 6 months after MSS, and changes in landmarks and variables were measured using a Rapidform 2006. Paired and independent t-tests were performed for statistical analysis.Results:Landmarks in the upper lip and mouth corner (cheilion, Ch) moved backward and downward (respectively, cupid bow point, 1.0 mm and 0.3 mm, P < .001 and P < .01; alar curvature-Ch midpoint, 0.6 mm and 0.3 mm, both P < .001; Ch, 3.4 mm and 0.8 mm, both P < .001). However, landmarks in stomion (Stm), lower lip, and chin moved backward (Stm, 1.6 mm; labrale inferius [Li], 6.9 mm; LLBP, 6.9 mm; B′, 6.7 mm; Pog′, 6.7 mm; Me′, 6.6 mm; P < .001, respectively). Width and height of upper and lower lip were not altered significantly except for a decrease of lower vermilion height (Stm-Li, 1.7 mm, P < .001). Chin height (B′-Me′) was decreased because of backward and upward movement of Me′ (3.1 mm, P < .001). Although upper lip projection angle and Stm-transverse projection angle became acute (Ch_Rt-Ls-Ch_Lt, 5.7°; Ch_Rt-Stm-Ch_Lt, 6.4°, both P < .001) because of the greater backward movement of Ch than Stm, lower lip projection angle and Stm-vertical projection angle became obtuse (Ch_Rt-Li-Ch_Lt, 10.8°; Ls-Stm-Li, 23.5°, both P < .001) because of the larger backward movement of Li than labrale superius (Ls).Conclusions:Three-dimensional soft tissue changes in Class III patients after MSS exhibited increased gradients from upper lip and lower lip to chin as well as from Stm to Ch.     

3D mandibular positioning after rapid maxillary expansion in Class II malocclusion

This study investigated, using cone beam computed tomography (CBCT), the spatial mandibular positioning after rapid maxillary expansion (RME) in Class II Division 1 malocclusion. This prospective study evaluated 17 children (mean initial age 10.36 years old) presenting Class II, Division 1 malocclusion and skeletal maxillary constriction that underwent to RME Haas' protocol. CBCT was performed before treatment (T1), immediately after the stabilization of expander screw (T2) and after the retention period of 6 months (T3). The scans were managed in Dolphin Imaging? 11.0 software, where landmarks (right and left condylion, right and left gonion, and menton) were positioned and measured in relation to sagittal, coronal and axial plane to verify, respectively, transverse, anteroposterior and vertical displacement of the mandible. Paired Student's t-test was used to identify significant differences (p<0.05) between T1 and T2, T2 and T3, and T1 and T3. After RME, right and left gonion moved downward (1.11 mm and 0.89 mm) and menton displaced downward (1.90 mm) and backward (1.50 mm). During the retention period, only anteroposterior displacement was significant, with the right and left gonion (0.97 mm and 1.26 mm) and the menton (2.29 mm) moving forward. Three-dimensional assessment of the mandible in Class II Division 1 patients subjected to RME showed a transitory backward and downward mandibular positioning, without any lateral displacement. The 6-month retention period allowed the mandible shifting significantly forward, exhibiting a more anterior position compared with the initial condition, even remaining in a more downward direction.     

Stability after surgical-orthodontic correction of skeletal Class III malocclusion. 2. Maxillary advancement.

Nearly half the patients with skeletal Class III malocclusion have maxillary deficiency as the major component of their problem, and modern surgical techniques allow maxillary osteotomy to correct the deformity. Changes at surgery and postsurgically were studied in 49 patients who underwent isolated surgical maxillary advancement. Thirty-one had wire osteosynthesis and maxillomandibular fixation, and 18 had rigid fixation with bone plates. In nearly half the patients, the maxilla was moved down as well as forward, indicating that the patient had both vertical and anteroposterior deficiency. In the anteroposterior plane, 80% of the patients had excellent stability at 1 year, while 20% had 2 to 4 mm of posterior movement of anterior maxillary landmarks. There was no difference in anteroposterior stability between wire/maxillomandibular fixation and rigid internal fixation groups. When the maxilla was moved down as well as forward, there was a strong tendency for relapse upward in both fixation groups. As a result, the chin frequently became more prominent from immediate postsurgery to 1-year followup, as upward movement of the maxilla allowed the mandible to rotate upward and forward.     

骨种植钉前牵引对骨性Ⅲ类错患者软硬组织侧貌的影响

目的研究采用骨种植钉前牵引对骨性Ⅲ类错患者软、硬组织侧貌的改变。方法选取18例需行前牵引矫治的生长发育期骨性Ⅲ类错患者,采用双侧上颌颧牙槽嵴植入骨种植钉配合面框式前牵引,平均治疗时间为9个月,力值为（3.5±0.1）N。治疗前后头影测量采用Legan&Burstone软组织分析法以及相关硬组织测量,分析比较患者治疗前后软、硬组织变化情况。结果所有患者Ⅲ类错均得到改善,鼻底趋于丰满,颏部顺时针旋转,侧貌由凹面型变为直面型,下唇突度减小,软组织上下面高比、鼻唇角、上唇突度及颏唇沟深度无明显变化。上前牙无明显变化,下前牙舌倾,上颌骨向前生长,A点前移,SNA、ANB增大;SNB减小,下颌骨顺时针旋转。结论骨种植钉前牵引可促进上颌生长,使面中份丰满,且对上颌前牙轴倾度无影响,从而纠正骨性Ⅲ类错。     

Kinematic analysis of mandibular motion before and after orthognathic surgery for skeletal Class III malocclusion: A pilot study

Objectives: The aim of the study was to detect the changes in 3D mandibular motion after orthognathic surgery for skeletal Class III malocclusion.

Method: Using a 3D motion analyzer, free mandibular border movements were recorded in nine patients successfully treated for skeletal Class III malocclusion and in nine patients scheduled for orthognathic surgery. Data were compared using Mann–Whitney non-parametric U-test.

Results: The results showed no differences between the groups in the total amount of mouth opening, protrusion, and in lateral excursions, but the percentage of mandibular movement explained by condylar translation was significantly increased after surgery (20% vs. 23.6%). During opening, the post-surgery patients showed a more symmetrical mandibular interincisal point and condylar path than pre-surgery patients (p < 0.01).

Discussion: Patients treated with orthognathic surgery for skeletal Class III malocclusion recover a good and symmetric temporomandibular joint function.     

Long-term skeletal and profile stability after surgical-orthodontic treatment of Class II and Class III malocclusion

ObjectiveThe purpose of this perspective research was to study the long-term stability of skeletal, dentoalveolar and soft tissue after orthognathic surgery in subjects presenting with Class II and Class III malocclusions.MethodsThe available digitized cephalometric radiographs, including pretreatment (t₀), presurgery (t₁), a minimum of 12 months postsurgery (t₂) and at least 3 years after the orthosurgery treatment (t₃) were taken between 1998 and 2010. In Group 1 mandibular advancement and in Group 2 mandibular advancement and maxillary impaction surgery were performed for correction of Class II. In Group 3 maxillary advancement and in Group 4 surgical maxillary advancement with mandibular setback, for correction of Class III.ResultsIn all the phases mandibular length was shorter in Group 1, and the inferior third of the face was longer in Group 2. Before the surgery there was greater maxillary deficiency in Group 3 than Group 4 and mandibular length was longer in Group 4.ConclusionIn Groups 1 and 2, at retention phase, relapse occurred due to the increase in mandibular plane, whereas the surgeries performed in Groups 3 and 4 remained stable.     

Camouflage treatment of skeletal Class III malocclusion with multiloop edgewise arch wire and modified Class III elastics by maxillary mini-implant anchorage

Objective:To evaluate the effect of the multiloop edgewise arch wire (MEAW) technique with maxillary mini-implants in the camouflage treatment of skeletal Class III malocclusion.Materials and Methods:Twenty patients were treated with the MEAW technique and modified Class III elastics from the maxillary mini-implants. Twenty-four patients were treated with MEAW and long Class III elastics from the upper second molars as control. Lateral cephalometric radiographs were obtained and analyzed before and after treatment, and 1 year after retention.Results:Satisfactory occlusion was established in both groups. Through principal component analysis, it could be concluded the anterior-posterior dental position, skeletal sagittal and vertical position, and upper molar vertical position changed within groups and between groups; vertical lower teeth position and Wits distance changed in the experimental group and between groups. In the experimental group, the lower incisors tipped lingually 2.7 mm and extruded 2.4 mm. The lingual inclination of the lower incisors increased 3.5°. The mandibular first molars tipped distally 9.1° and intruded 0.4 mm. Their cusps moved 3.4 mm distally. In the control group, the upper incisors proclined 3°, and the upper first molar extruded 2 mm. SN-MP increased 1.6° and S-Go/N-ME decreased 1.Conclusions:The MEAW technique combined with modified Class III elastics by maxillary mini-implants can effectively tip the mandibular molars distally without any extrusion and tip the lower incisors lingually with extrusion to camouflage skeletal Class III malocclusions. Clockwise rotation of the mandible and further proclination of upper incisors can be avoided. The MEAW technique and modified Class III elastics provided an appropriate treatment strategy especially for patients with high angle and open bite tendency.     

Camouflage treatment of skeletal Class III malocclusion with asymmetry using a bone-borne rapid maxillary expander

This case report presents the successful use of palatal mini-implants for rapid maxillary expansion and mandibular distalization in a skeletal Class III malocclusion. The patient was a 13-year-old girl with the chief complaint of facial asymmetry and a protruded chin. Camouflage orthodontic treatment was chosen, acknowledging the possibility of need for orthognathic surgery after completion of her growth. A bone-borne rapid expander (BBRME) was used to correct the transverse discrepancy and was then used as indirect anchorage for distalization of the lower dentition with Class III elastics. As a result, a Class I occlusion with favorable inclination of the upper teeth was achieved without any adverse effects. The total treatment period was 25 months. Therefore, BBRME can be considered an alternative treatment in skeletal Class III malocclusion.     

成人骨性Ⅱ类错畸形上气道与上、下颌骨形态分析

目的: 应用锥形束CT（CBCT）分析骨性Ⅱ类错畸形患者上气道与上、下颌骨形态的相关关系。方法: 选择骨性Ⅱ类及骨性Ⅰ类错畸形成年患者各33例进行CBCT扫描,保存为Dicom文件,导入Mimics 19.0软件中进行三维重建,对2组患者上气道与上、下颌骨数据进行测量。采用SPSS 19.0软件包进行统计学分析,比较成人骨性Ⅱ类错与个别正常间上气道与上、下颌骨形态、结构的差异,以及骨性Ⅱ类错畸形患者上气道与上、下颌骨测量项目的相关关系。结果: 骨性Ⅱ类错组和个别正常组上气道形态与上、下颌骨测量结果比较,15个测量项目有显著差异(P<0.05)。骨性Ⅱ类错组上气道形态与下颌骨长度存在相关性的项目有10个,骨性Ⅱ类错组上气道形态与上颌骨宽度各测量项目中有显著相关性的项目有13个,骨性Ⅱ类错组上气道形态与下颌骨宽度各测量项目中有显著相关性的项目有3个。结论: 骨性Ⅱ类错畸形患者上气道与上、下颌骨之间具有相关关系。骨性Ⅱ类成人患者的上气道与上、下牙弓宽度也有一定相关关系。