Comparison of the changes in facial profile after orthodontic treatment,with and without extractions.

Abstract

A study was made of 31 patients with Angle Class II malocclusion. Fifteen patients did not undergo extraction of teeth (Group A), while 16 underwent extractions of four premolars (Group B). Data was obtained from the corresponding lateral radiographs of the head taken both before and after orthodontic treatment. The main aim of the study was to compare the response of the soft and hard tissues of the facial profile in Class II malocclusion treated with the extraction of four premolars and the response of borderline cases presenting with similar malocclusions, but not subjected to extraction. In this latter group reasonable doubt existed as to whether or not to remove teeth in order to solve the occlusal and aesthetic problems. It is concluded that significant hard tissue differences between the groups at the end of treatment were limited to a more retruded position of the incisors and a reduced overbite amongst those patients subjected to extraction. The main soft tissue differences between the groups at the end of treatment were a more retruded lower lip and a more pronounced lower labial sulcus in those patients subjected to extraction.     

Changes in the soft tissue profile after extraction orthodontic therapy

PURPOSE: The purpose of this study was to evaluate the effects of extraction therapy and use or nonuse of headgear on the soft tissue profile in subjects with different growth patterns. METHODS: A total of 41 subjects were included in the study. The patients were treated with standard edgewise mechanics and had 4 first premolars extracted. The type of growth pattern was assessed as mesiodivergent or hyperdivergent. The results were analyzed by 2-way analysis of variance. RESULTS: When comparing the mean changes between growth pattern types, the vertical changes in Sn and A' were found to be statistically significant (P<.05). The vertical change in A' was also found to be significant between the headgear use and nonuse groups (P<.05). Interaction was found to be significant for Steiner upper and lower lip values and the vertical change in A. The upper and lower lips were retracted significantly more by headgear use in patients with hyperdivergent growth pattern (P<.05). CONCLUSIONS: The results of this study indicate that the use of headgear should be avoided in hyperdivergent patients. The avoidance of premolar extraction, based on the possibility of a significant detrimental effect on the facial profile, is not justified.     

Changes in the soft tissue chin after orthodontic treatment

The study envisages changes in the contour of the soft tissue chin immediately and 5 years after orthodontic treatment in a group of 31 male and 29 female patients. The group was classified according to facial types and whether treatment involved extraction of first premolar teeth. The average age before treatment was 10 years 7 months, immediately after treatment it was 14 years 6 months, and 5 years after treatment was 21 years 6 months. The chin contour was studied from cephalometric x-ray tracings. The facial types--mesofacial, brachyfacial, and dolichofacial--were identified on the basis of cephalometric analysis. The chin thickness was registered at six different locations around the symphysis, from the point on the soft tissue chin corresponding to B point to the chin point corresponding to menton. Statistical means and standard deviations for all of the six chin thicknesses were calculated. It was found that the overall soft tissue chin thickness increased after orthodontic treatment. The females had less increase at all levels than the males. The dolichofacial group showed a greater increase in the soft tissue chin thickness after treatment. The mesofacial and brachyfacial groups of females showed no statistically significant increases. Regression tests of independent variables, including age, sex, facial type, and such other cephalometric measurements as 1 - A Pog, 1 to A Pog, mandibular plane, mandibular arc, facial axis, lower face height, and classification of malocclusion, indicated that age, sex, and facial type were the only variables that influenced the soft tissue chin thickness.     

Predicting soft tissue profile changes concurrent with orthodontic treatment

Two studies related to soft tissue profile change, are reported in this paper. In the first study, 50 adults with normal occlusion were compared to 50 adults with maxillary protrusion. Cephalometric radiographs were obtained for all subjects in two positions: with lips relaxed and lips closed. The amount of lower lip movement increased in relation to the degree of maxillary protrusion. In both groups, thickness of soft tissue pogonion decreased with upward movement of the lower lip. In the second study, 20 posttreatment patients were examined to determine how soft tissue profile is related to the morphologic alterations of treatment. Ten patients were treated for maxillary protrusion and 10 for bimaxillary protrusion. Upper lip retraction was about 40 percent of the maxillary incisor retraction. Cases with maxillary protrusion showed slightly less soft tissue change than cases with bimaxillary protrusion. Lower lip retraction was about 70 percent of the maxillary incisor retraction. With an understanding of pretreatment lip posture and data related to the soft tissue response to treatment, a framework is presented for predicting a patient's posttreatment facial profile.     

双颌手术后颜面软组织侧貌改变的研究

目的 研究下颌前突伴上颌骨发育不全患者术后颜面软组织侧貌改变.方法 对20例下颌前突伴上颌骨发育不足病例进行术前后Χ线头影测量研究,用SPSS软件对测量值进行统计分析.结果 下唇突点(LI点)、颏唇沟点(Si点)软组织颏前点(PG点)分别以下中切牙点(li点)下牙槽座点(B点)硬组织颏前点(pg点)的92%、97%、92%后移而后移,并得出了相应的回归方程.结论 上颌软硬组织改变无明显相关性,下颌软硬组织改变有非常显著相关性.     

Axiographic findings in patients undergoing orthodontic treatment with and without premolar extractions

Mechanical axiography was performed on 49 (37 female, 12 male) patients prior to orthodontic treatment, after removal of the fixed appliance, and at the end of retention. Twenty-five subjects (mean age 12.8 years) underwent orthodontic treatment without premolar extractions (group 1) and 24 subjects (mean age 13.5 years) with premolar extractions (group 2). The axiographic tracings of the protrusive movements were analysed using a digitizer and specially designed software. A statistically significant increase (P < 0.05) in the values for horizontal condylar inclination (HCI) was found for both groups over the entire observation period. Group 1 showed a higher increase (P < 0.05) between the beginning of treatment and removal of the brackets, and group 2 between bracket removal and the end of retention. At the end of retention, a similar increase in HCI values was found for both groups. Over the observation period, the frequency of pathological axiographic findings decreased, which seems to be a positive effect of orthodontic treatment.     

颏部形态与边缘型牙列拥挤拔牙非拔牙矫治的相关性研究

目的 研究边缘型牙列拥挤病例正畸治疗前X线头颅侧位片,分析颏部形态在颅面部硬组织侧貌形态中的作用,及其是否可作为临床矫治设计中判断是否拔牙的指标.方法 选取15～18岁之间的边缘型牙列拥挤患者50名,根据治疗方法分为拔牙组与不拔牙组.选取反映硬组织面型特征的指标21项,对2组患者治疗前头颅侧位片进行测量分析,比较拔牙组与不拔牙组间测量项目有无差异,及颏部形态与测量项目之间的相关关系,判断代表颏部形态的指标Pog-NB是否可以作为临床矫治设计中判断是否拔牙的敏感指标.结果 代表颏部形态的指标Pog-NB在两组之间存在显著性差异.Pog-NB因素对决定拔牙与否的影响最大.Pog-NB与L1-NB、L1-NP、U1-NP、L1-AP、A-NFL、UL-EP存在高度相关关系.证明了颏部形态对正畸矫治拔牙设计有影响.结论 当上颌倾斜度、突度相对于前颅底平面一致时,颏部突度的大小对预测矫治后下切牙应处的位置有重要意义,可通过Pog-NB值来判断边缘型牙列拥挤拔牙或非拔牙矫治.颏部形态对决定边缘型牙列拥挤拔牙与否有重要的影响.当颏凸较小、拔牙的概率大.反之当颏凸较大、颏点位置靠前时,拔牙的概率较小.     

青少年双颌前突患者拔牙矫治前后侧面部软组织改变的研究

目的 研究青少年双颌前突患者拔牙矫治前后侧面部软组织的改变。方法 对34名青少年双颌前突患者拔牙矫治前后的18项侧面部软组织指标进行对比,通过配对t检验来分析治疗后侧面部软组织的改变。结果 18项软组织指标中5项角度指标的改变在男性组与女性组的改变均有统计学意义,13项线距测量指标中的上唇厚度、下唇厚度、鼻凸度均增大,而鼻底厚度在男性组与女性组改变不同。结论 青少年双颌前突患者拔牙矫治前后面部凸度减小,男性与女性上唇、下唇的变化不同,患者的鼻、唇、颏关系得到改善,软组织侧貌发生明显改变。?     

Changes in soft tissue profile after surgical correction of skeletal class III malocclusion.

Cephalometric analysis of the facial soft tissue profile after surgical correction of skeletal Class III malocclusion performed either in the ascending ramus or in the mandibular body in 33 patients showed a close correlation between the horizontal movements of the soft tissue landmarks and those of the underlying skeletal and dental structures. In the vertical direction, the changes were more variable. A comparison of these results with the soft tissue profile of normal persons indicated that a natural appearance could be achieved after correction of Class III malocclusion by combined surgery and orthodontic treatment.     

骨性下颌前突患者正畸与外科联合治疗前后颌面软硬组织变化研究

目的 探讨骨性下颌前突畸形联合治疗后其颌面软硬组织的变化情况。方法 对20例骨性下颌前突患者行正畸与外科联合治疗后,通过X线头影测量方法分析治疗前后软硬组织变化情况。结果 仅下齿槽座点与下唇沟点在治疗前后的变化量在垂直方向的分量之间无相关性,其余各组软硬组织对应点的变化量之间均有相关性,其中在前后方向上,软硬组织对应点（除上齿槽座点与上唇沟之间）之间均呈高度相关性。结论 骨性下颌前突畸形经联合治疗后,其颌面部软硬组织对应点的变化量是基本一致的,这种一致性在前后方向上比垂直方面上更为理想。     

Changes in soft tissue profile during the treatment of Class III malocclusion

The changes in soft tissue profile for 66 Angle's Class III malocclusion subjects treated either with the Function Regulator, or Upper Removable Appliances, or the Edgewise Appliance were assessed by comparing cephalometric radiographs taken before and after correction of the anterior occlusion. While the mean soft tissue profile in all groups improved in relation to a Control Group, the FR.III Group demonstrated the most profound change.     

Begg矫治技术对面部软组织侧貌的影响

目的研究Begg技术矫治过程对患者颜面测貌的影响。方法借助X线头影测量技术，对32例采用Begg技术矫治的AngleⅡ类I分类错患者的颜面侧貌变化过程进行研究。结果矫治的第一、二阶段是面部软组织侧貌发生根本性改善的关键，而第三治疗阶段对面部软组织侧貌的影响几乎没有。结论Begg技术在改善颜面软组织侧貌更符合临床需求；在矫治第二阶段应强调取得协调的面部软组织侧貌这一目标，并以此建立关系。