The time-course change in the lip closing force in Class III malocclusion after orthognathic surgery

ObjectivesThe purpose of this study was to examine the changes with time in lip pressure after orthognathic surgery for skeletal Class III patients.Study designThe subjects consisted of 63 patients (32 female and 31 male) diagnosed with mandibular prognathism who underwent sagittal split ramus osteotomy with and without Le Fort I osteotomy. Maximum and minimum lip closing forces were measured with Lip De Cum^®. The changes with time were compared statistically.ResultsThe maximum and minimum lip closing force increased time-dependently in men and women after surgery and there were significant differences between men and women with changes with time in the maximum lip closing force (p = 0.0086) and the minimum lip closing force (p = 0.0302). After 1 year, the Class III group maximum lip closing force was significantly smaller than the control group in both men (p < 0.0001) and women (p < 0.0001).ConclusionsThis study suggests that there was significant difference in over time in the lip closing force between men and women in Class III patients. Although the maximum lip closing force increased with time, it did not reach the level of the control group after 1 year.     

Postural assessment in class III patients before and after orthognathic surgery

Purpose

This study aimed to assess body posture before and after bimaxillary orthognathic surgery by photogrammetry in skeletal class III patients.

Methods

Thirty-one patients with skeletal class III dentofacial deformities (14 men, 17 women) who underwent orthodontic preparation for surgery were included in this non-randomized controlled trial. Of these, 15 who did not undergo orthognathic surgery during the period of this study served as controls. Postural assessment was performed by photogrammetry using SAPO® (Postural Assessment Software) based on anterior-, posterior-, and lateral-view images taken 1 month before and 4 months after bimaxillary orthognathic surgery with internal rigid fixation (or 4 months after the initial assessment, for the control group). The study was approved by PUCRS Research Ethics Committee, and written informed consent was obtained from all individual participants prior to their inclusion in the study.

Results

There was no significant difference between groups for age, gender, and GAP. In the intervention group, the right leg/hindfoot angle, which initially indicated a valgus deformity, normalized after intervention (P?<?0.048). Posterior displacement of the head (P?<?0.005) and trunk (P?<?0.004) were observed after intervention.

Conclusions

These results suggest that correction of class III dentofacial deformities by bimaxillary orthognathic surgery can produce systemic postural adjustments, especially posterior displacement of the head and trunk and knee and ankle valgus.

     

成人严重骨性Ⅲ类错(牙合)畸形手术前后的正畸治疗

目的:研究成人严重骨性Ⅲ类错(牙合)畸形在正颌外科治疗的术前与术后正畸的特点及难点.方法:成人严重骨性Ⅲ类错(牙合)病例35例,对该类畸形的临床特点、正颌手术前后正畸治疗方法和注意事项进行分析研究.结果:术前正畸治疗必须完成个别牙齿错位的调整,纠正牙弓形态与宽度的不调和牙齿代偿的去除;术后正畸的主要目的是牙弓内残留间隙的关闭和咬合关系的进一步精细调整.结论:只有完善的术前、术后正畸治疗与正颌外科手术相互配合,才能较好地完成成人严重骨性Ⅲ类错(牙合)的临床治疗.     

Changes in the chewing path of patients in skeletal class III with and without asymmetry before and after orthognathic surgery.

PURPOSE: The purpose of this study was to examine the relation between changes in the condylar long axis and the chewing path before and after mandibular ramus osteotomy for patients with prognathism with and without asymmetry. PATIENTS AND METHODS: Eleven men and 16 women with mandibular prognathism were divided into groups on the basis of symmetry and osteotomy procedure. Preoperative and postoperative frontal chewing paths were recorded. The chewing path consisted of 4 components: deviated side range, undeviated side range, vertical range, and incisal path angle. The angle of the condylar long axis and the 4 components of the chewing path were compared between groups and the differences were analyzed statistically. RESULTS: No significant differences in each of the 4 chewing path components were found between groups on the basis of symmetry or osteotomy procedure. A positive correlation was found between the changes in incisal path angle when chewing on the undeviated side and condylar long axis angle on the undeviated side (P < .05). A positive correlation was also found between the changes in undeviated side range when chewing on the deviated side and condylar long axis angle on the deviated side (P < .05). CONCLUSION: This study suggests that surgically induced increase in the condylar long axis is correlated with increase in side range and incisor path angle, although surgical orthodontic treatment does not significantly change the chewing pattern.     

Evaluation of recovery in lip closing pressure and occlusal force and contact area after orthognathic surgery

PurposeThe purpose of this study was to evaluate the relationship between lip closing force, occlusal contact area and occlusal force after orthognathic surgery in skeletal Class III patients.Subjects and methodsThe subjects consisted of 54 patients (28 female and 26 male) diagnosed with mandibular prognathism who underwent sagittal split ramus osteotomy with and without Le Fort I osteotomy. Maximum and minimum lip closing forces, occlusal contact area and occlusal force were measured pre-operatively, 6 months and 1 year post-operative.ResultsMaximum and minimum lip closing forces, occlusal contact area and occlusal force increased with time after surgery, however a significant increase was not found in the occlusal contact area in women. In increased ratio (6 months/pre-operative and 1 year/pre-operative), the maximum lip closing force was significantly correlated with the occlusal contact area (P < 0.0001).ConclusionsThis study suggested that orthognathic surgery could improve the occlusal force, contact area and lip closing force, and an increase ratio in maximum lip closing force was associated with an increased ratio in occlusal contact area.     

Dentoskeletal parameters related to visual perception of facial asymmetry in patients with skeletal class III malocclusion after orthognathic surgery

The purpose of the study is to explore the critical parameters determining the visual perception of postoperative facial symmetry. This study retrospectively included 24 patients with skeletal class III malocclusion and double-jaw orthognathic surgery (OgS). The patients were classified according to the outcome of subjective visual perception scores (SVPS) based on the postoperative frontal images by 10 orthodontists: symmetrical surgical outcome (S group, n = 12) and facial asymmetry after surgery (A group, n = 12). The 3D dentofacial measurements from cone beam computed tomography, were compared between the S and A groups. The relationship of all variables in all patients with the SVPS was explored by Spearman correlation coefficient. Significant differences were observed in the midline parameters in the mandible, the B point, gnathion and menton, and the mandibular border axis as well as in the discrepancy of the chin morphology between the two groups (P < 0.05). The findings demonstrated that the midline parameter deviation, shape of the mandibular border, and the contour of menton morphology play the major role in the visual perceptions of postoperative asymmetry.     

骨性III类错畸形患者正颌手术前后力变化的初步研究

目的:应用计算机咬合分析系统,评价正颌手术前后骨性III类错牙合患者牙合力的变化。方法:收集15例骨性III类错牙合需正颌手术病例,利用T-ScanII牙合诊断分析系统在术前1周内、术后3个月和术后6个月时对患者的牙合力进行测定,分析患者的总牙合力(TOF)、MIP/MAX指数、牙合力不对称指数(AOF)、牙合力中心点位置(COF)及咀嚼时最大位移距离(MCOF),应用配对t检验进行比较研究。结果:术后3个月时TOF有所上升,6个月时与术前水平相比已有显著差异(P<0.05),说明患者牙合力水平已有提高。MIP/MAX指数略有下降,但6个月时增大并超过术前水平。AOF术后呈下降趋势,在3个月和6个月时均比术前显著减小(P<0.01,P<0.001)。术后COF逐渐接近正常,MCOF减小,术后6个月时均较术前明显改善,说明患者牙合力水平已有提高。结论:正颌正畸联合治疗能够改善骨性III类错牙合患者的牙合力水平及力平衡性。     

Changes in border movement of the mandible in skeletal Class III before and after orthognathic surgery

The purpose of this study was to examine the changes in border movement of the mandible before and after mandibular ramus osteotomy in patients with prognathism. The subjects were 73 patients with mandibular prognathism who underwent sagittal split ramus osteotomy (SSRO) with and without Le Fort I osteotomy. Border movement of the mandible was recorded with a mandibular movement measure system (K7) preoperatively and at 6 months postoperatively. Of the 73 patients, 21 had measurements taken at 1.5 years postoperative. Data were compared between the pre- and postoperative states, and the differences analyzed statistically. There was no significant difference between SSRO alone and SSRO with Le Fort I osteotomy in the time-course change. The values at 6 months postoperative were significantly lower than the preoperative values for maximum vertical opening (P = 0.0066), maximum antero-posterior movement from the centric occlusion (P = 0.0425), and centric occlusion to maximum opening (P = 0.0300). However, there were no significant differences between the preoperative and 1.5 years postoperative measurements. This study suggests that a postoperative temporary reduction in the border movement of the mandible could recover by 1.5 years postoperative, and the additional procedure of a Le Fort I osteotomy does not affect the recovery of mandibular motion after SSRO.     

Changes in bite force and dentoskeletal morphology in prognathic patients after orthognathic surgery

OBJECTIVE: We sought to evaluate the changes in bite force and dentoskeletal morphology in prognathic patients after orthognathic surgery. STUDY DESIGN: Twenty-four patients underwent orthognathic surgery to correct Class III skeletal and dental malocclusions. Ten patients who underwent Le Fort I and bilateral sagittal split ramus osteotomy of the mandible (ie, surgical correction of 2 jaws) and 14 patients who underwent only bilateral sagittal split ramus osteotomy (ie, surgical correction of 1 jaw) were compared. Bite force was measured preoperatively and at 3, 6, and 12 months postoperatively. The dentoskeletal morphology was assessed through lateral cephalograms obtained preoperatively and 12 months postoperatively. RESULTS: Twelve months postoperatively, the bite force was significantly greater in the patients who underwent surgery on 1 jaw than in the patients who underwent surgery on 2 jaws. Significant decreases in the gonial angle, occlusal plane angle, and anterior facial height were observed postoperatively in the patients with 1 surgically corrected jaw, but not in the patients with 2 surgically corrected jaws. Patients with 2 surgically corrected jaws experienced a greater increase in the Frankfort mandibular plane angle and a greater decrease in the posterior facial height than did those with 1 surgically corrected jaw. CONCLUSION: The difference in the preoperative-to-postoperative change in dentoskeletal morphology between the 2 groups is one of the factors responsible for the significant difference in postoperative bite force between the 2 groups.     

Smile attractiveness in class III patients after orthodontic camouflage or orthognathic surgery

Clinical Oral Investigations - The study’s objective was to compare the smile attractiveness in patients with class III malocclusion treated with orthodontic camouflage or orthognathic...     

Three-dimensional investigation of facial surface asymmetries in skeletal malocclusion patients before and after orthodontic treatment combined with orthognathic surgery

Objectives

The goal of the following study was to quantify facial soft-tissue asymmetry in patients with pronounced skeletal malocclusion anomalies before and after orthodontic treatment combined with orthognathic surgery. In addition, the facial attractiveness of these patients was rated by dental specialists and laypersons both before and after treatment based on the three-dimensional (3D) data.

Patients and methods

An optical sensor was used to noninvasively capture the 3D facial surface data of 60 adult patients including two groups of 20 patients with skeletal Class II or III anomalies and a control group of another 20 subjects with Class I relationships. Facial surface asymmetries were evaluated immediately before the surgical procedure and 1 year thereafter. In addition, subjective ratings of facial attractiveness were obtained based on a questionnaire from orthodontists, maxillofacial surgeons, and laypersons.

Results

No differences in facial soft-tissue asymmetry were observed between the Class II and III patients either pre- or postoperatively, but asymmetry was found to be more pronounced in the skeletal malocclusion groups than in the Class I control group both pre- and postoperatively. The subjective ratings of facial attractiveness by the various rater groups yielded more favorable results for the post- than preoperative patient images, reflecting differences that reached overall statistical significance.

Conclusion

Quantitative analysis of facial soft-tissue asymmetry and calculating a cutoff value allowed us to distinguish patients with skeletal malocclusion from a control group solely on the basis of asymmetry. Combined regimens of orthodontic treatment and orthognathic surgery go some way in reducing asymmetry toward the levels seen in untreated control subjects, while the asymmetry pattern characteristic of this type of malocclusion will persist. Nevertheless, the asymmetry reduction is noticeable enough to result in more favorable ratings of attractiveness.     

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.     

骨性Ⅲ类错牙合上颌拔牙与不拔牙去代偿对双颌手术矫治效果的影响

目的评价骨性Ⅲ类畸形双颌手术患者术前正畸上颌拔牙与不拔牙去代偿的效果及对术后的影响。方法选取36例在中国医科大学口腔医院进行正畸正颌外科联合治疗的骨性Ⅲ类错牙合畸形患者,其中18例术前正畸采取拔牙矫治,另18例未拔牙。对2组病例术前正畸后及治疗结束后的X线头颅定位侧位片进行对比研究。结果术前正畸后,拔牙组的U1-SN、鼻唇角（Cm-Sn-UL）和覆盖都较非拔牙组有明显变化,差异有统计学意义（P<0.05）。拔牙组下颌平均后退（8.66±1.42）mm,非拔牙组下颌平均后退（6.21±3.06）mm,二者间差异有统计学意义（P<0.05）;治疗结束后,拔牙组ANB、U1-SN、NA-PA在正常值范围内（P>0.05）。结论在骨性Ⅲ类畸形的正畸正颌外科联合治疗中,上颌拔牙术前正畸能够更彻底地去代偿,真实反映原有骨性畸形,使下颌能够后退至更加理想的位置,从而更好地矫治凹面型。     

Temporomandibular dysfunction in 1,516 patients before and after orthognathic surgery

Functional disturbances, together with esthetic considerations, are important reasons for patients to seek orthognathic surgical treatment. Functional disorders may include signs and symptoms of temporomandibular disorders (TMD), such as joint pain, chewing problems, joint noises, headaches, etc. This paper reports on TMD before and after orthognathic surgery in 1,516 patients. It is based upon the patients' own evaluations as recorded 2 years after surgery. Preoperatively 43% and postoperatively 28% of the patients reported subjective symptoms of TMD. This difference indicates an overall beneficial effect of orthognathic surgery on TMD signs and symptoms. Patients with mandibular retrognathia did not improve as much as patients with mandibular prognathia. Sagittal ramus osteotomy was less effective than vertical ramus osteotomy in relieving TMD symptoms when performed on similar diagnoses.     

Treatment decision in adult patients with Class III malocclusion: orthodontic therapy or orthognathic surgery?

Class III malocclusion is one of the most difficult anomalies to understand. Because not all Class III patients are candidates for surgical correction, patient assessment and selection remain main issues in diagnosis and treatment planning. The purpose of this study was to separate Class III patients who can be properly treated orthodontically from those who require orthognathic surgery. A large sample size was a necessary to obtain a sufficiently robust model. Thus, a multicentric study design was chosen (Orthodontic Departments of the Universities of Frankfurt, Heidelberg, and Würzburg, Germany). The cephalograms of 175 adult patients with Class III malocclusions were analyzed. The orthodontic group comprised 87 patients, and the surgery group, 88 patients. Twenty linear, proportional, and angular measurements were made. Stepwise discriminant analysis was applied to identify the dentoskeletal variables that best separate the groups. The discriminant function model was highly significant (P <.0001); 92% of the patients were correctly classified. The following variables were extracted: Wits appraisal, length of the anterior cranial base, maxillary/mandibular (M/M) ratio, and lower gonial angle. The resulting equation was: Individual score = -1.805 + 0.209. Wits + 0.044. S-N + 5.689. M/M ratio - 0.056. Go(lower). By means of discriminant analysis, correct classification of adult Class III malocclusion patients succeeded to a very high degree. Of all the variables, the Wits appraisal was the most decisive parameter.     

Children with class III malocclusion: development of multivariate statistical models to predict future need for orthognathic surgery

Until now, the literature does not provide an accurate model to predict the future need for orthognathic surgery in prepubertal patients with class III malocclusion. Because not all of these patients are candidates for later surgical correction, patient assessment and selection remain arbitrary with respect to diagnosis and treatment planning. The purpose of the present investigation was to analyze the value of classifying class III children before puberty into patients who can be effectively treated by orthopedic/orthodontic therapy alone and those who require orthognathic surgery. To obtain a robust model, the study design was multicentric (University Orthodontic Departments of Frankfurt, Heidelberg, and Würzburg). A total of 88 patients with class III malocclusion were grouped into orthopedic/orthodontic (n = 65) and surgery patients (n = 23), according to their records after puberty (mean age, 17 years three months). Discriminant analysis (DA) and logistic regression (LogR) were applied to 20 landmarks of the patients' cephalograms before puberty (mean age, nine years eight months) to identify the dentoskeletal variables that provide the best group separation and the best predictability of group membership, respectively. Both models were highly significant (P < .001), classifying 93.3% (DA) and 94.3% (LogR) of the patients correctly. The extracted variables were identical for both procedures: Wits appraisal, palatal plane angle, and individualized inclination of the lower incisors. The resulting equation of LogR was individual score = -7.968 - 1.323Wits - 0.363NL-NSL + 0.153[180 - (LI-ML) - (L1-ML(ind))]. We concluded that by means of multivariate statistics, prepubertal children with class III malocclusions may be classified into nonsurgery and surgery patients with high accuracy.     

骨性Ⅲ类错(牙合)畸形患者正颌手术前后(牙合)力变化的初步研究

目的:应用计算机咬合分析系统,评价正颌手术前后骨性Ⅲ类错(牙合)患者(牙合)力的变化.方法:收集15例骨性Ⅲ类错(牙合)需正颌手术病例,利用T-Scan Ⅱ(牙合)诊断分析系统在术前1周内、术后3个月和术后6个月时对患者的(牙合)力进行测定,分析患者的总(牙合)力(TOF)、MIP/MAX指数、(牙合)力不对称指数(AOF)、(牙合)力中心点位置(COF)及咀嚼时最大位移距离(MCOF),应用配对t检验进行比较研究.结果:术后3个月时TOF有所上升,6个月时与术前水平相比已有显著差异(P＜0.05),说明患者(牙合)力水平已有提高.MIP/MAX指数略有下降,但6个月时增大并超过术前水平.AOF术后呈下降趋势,在3个月和6个月时均比术前显著减小(P＜0.01,P＜0.001).术后COF逐渐接近正常,MCOF减小,术后6个月时均较术前明显改善,说明患者(牙合)力水平已有提高.结论:正颌正畸联合治疗能够改善骨性Ⅲ类错(牙合)患者的(牙合)力水平及(牙合)力平衡性.     

成人错畸形患者正颌手术治疗决策的质性研究

目的 深入了解和探讨国内成人错畸形患者正颌手术的决策体验。方法 采用定性描述性研究方法,以目的抽样选取2018年1月—3月就诊的10例患者为研究对象,以面对面、半结构式深入访谈的形式收集资料,并运用Colaizzi内容分析法对资料进行整理与分析。结果 通过资料的归纳分析,总结出2个主题,即治疗动机、治疗决策干扰因素。结论 错畸形患者正颌手术治疗决策的信息服务具有局限性,需要进一步研究以完善支持错畸形患者治疗决策的信息服务,帮助患者做出最佳的选择。