上颌单侧拔牙矫治牙列拥挤的临床体会

在正畸矫治牙列拥挤的过程，为获得间隙常需要拔牙矫治，同时为了保持牙弓中线与面部中线协调一致、牙弓左右对称以及上下颌匹配多采用对称性拔牙。然而在某些特殊情况下，如拥挤集中于牙弓一侧；下颌切牙先天缺失；前牙区Bolton指数不调；患者要求少拔牙、缩短治疗时间时，可以尝试采用不对称拔牙进行矫治。不对称拔牙的矫治设计多种多样，本文将对拔除上颌单侧双尖牙的情况进行分析和总结。     

下颌第三磨牙与正畸治疗后下前牙出现拥挤的关系

下颌第三磨牙与正畸治疗固位停止后下前牙出现拥挤的关系,在以往的报告中意见颇不一致。作者通过研究拟进一步了解下颌第三磨牙是否影响正顺治疗后下牙弓的变化,特别是对下前牙拥挤复发的影响。     

快速扩弓和方丝弓技术治疗错(牙合)畸形疗效稳定性的长期观察

为了提高正畸治疗的稳定性,防止复发,人们采用了许多方法如过度矫治,避免过度扩弓,延长保持时间,但保持结束后经常可见牙弓长度宽度减小,前牙出现拥挤,覆(牙合)覆盖增大。曾有报道对应用Edgewise技术治疗后牙弓长期稳定性评价,但多集中于下颌。本研究对快速扩弓和Edgewise技术治疗后上下颌疗效的     

Angle氏Ⅱ'错矫治后下切牙长期稳定性研究

本研究的目的在于评价一组分类患者经固定正畸治疗取得良好关系及牙齿排列后，其下颌切牙的长期稳定性，旨在揭示复发的指征及复发与保持阶段变化因素的关系。78例错的选择指征为：治疗后的模型显示后牙咬会关系良好，前牙覆始覆盖正常，包括非拔牙组及拔干〔两组，所有患者的研究资料包括治疗前、治疗后及保持14年后的现存模型及头颅侧位片。研究结果表明：经长期追踪观察下切牙会发生排列异常，尖牙间距减小及牙弓长度缩短，其中有9．0％的患者下切牙区的拥挤达6．smm，47．4％的患者下切牙区的拥挤度为3．smm或更小。用多元逐步回归…     

MBT矫治前后牙弓宽度变化的模型分析研究

目的 分析牙列拥挤患者不拔牙与拔牙的MBT矫治对牙弓宽度变化的影响。方法 选择我院正畸科2008—2011年MBT矫治器治疗的牙列拥挤患者40例。其中轻中度牙列拥挤患者20例,使用MBT矫治器进行不拔牙正畸;中重度牙列拥挤患者20例,使用MBT矫治器进行拔除4颗第一前磨牙的拔牙正畸。测量术前术后石膏模型的牙弓宽度,对矫治前后不拔牙组和拔牙组的测量数据分别进行组内、组间统计学分析。结果 矫治前后不拔牙组:上颌尖牙间宽度增大,上下颌第一前磨牙、第一磨牙间宽度增大,有统计学意义;拔牙组:上颌尖牙间宽度增大,上下颌第二前磨牙、第一磨牙间宽度变小,有统计学意义。矫治前2组上下颌尖牙、第一磨牙间牙弓宽度相近,无统计学差异;矫治后不拔牙组上下颌第一磨牙间牙弓宽度大于拔牙组,有统计学意义,2组上下颌尖牙间牙弓宽度相近,差异无统计学意义。结论 不拔牙矫治牙弓宽度变化与拥挤部位、拥挤程度有关,拔牙矫治牙弓宽度变化主要与牙齿移动方向有关。拔牙矫治后尖牙间宽度不会减小。     

下颌第三磨牙对矫治后牙弓长度宽度变化的比较研究

目的:探讨下颌第三磨牙的存失状态对矫治后下颌牙弓长度和宽度的改变。方法:随机抽取符合条件的54例,其中先天缺失下颌第三磨牙胚26例,下颌第三磨牙胚存在的28例。对矫治结束和保持3年后的模型进行下颌牙弓长度和宽度测量,卡方分析。结果:测量分析发现2组病例中,牙弓宽度变化无统计学意义,而下颌牙弓长度2组有显著性差异。有第三磨牙胚组,保持3年后下颌牙弓长度平均增加1.9mm,下前牙拥挤平均为1.5mm,而无第三磨牙胚组下颌牙弓长度增加1.0mm,下前牙拥挤平均为0.7mm。结论:下颌第三磨牙的萌出对下颌牙弓产生一定的压力,增加了下颌牙弓的长度,同时也出现了下前牙拥挤,对非拔牙的边缘性病例和有复发趋势的病例,应尽早拔除第三磨牙。以防止出现术后下颌前牙再度拥挤。     

生长发育与前牙反（牙合）的正畸治疗

前牙反（牙合）的正畸治疗一直是正畸学界的热点话题，其治疗计划的确立、方法的选择以及长期稳定性的预测都与对前牙反殆的生长发育潜力，即前牙反（牙合）个体生长量及生长方向密切相关。此外，确定生长发育所处的阶段对于前牙反（牙合）正畸治疗开始时间及治疗后的保持时间也有重要意义。尽管造成前牙反（牙合）正畸治疗后复发的因素很多，如诊断错误、矫正器的不正确使用及不恰当的矫正技术等，但是正畸医生却不可否认在正畸治疗后的一段时间内颅颌面的持续的生长发育潜力，也可以是导致复发的一个重要因素。     

减数拔牙后正畸治疗中断情况下牙齿漂移的研究

目的 比较不同类型患者减数拔牙后正畸治疗中断1.5月（45 d）后牙齿漂移的程度。方法 本研究已通过单位伦理委员会审查批准,并获得患者知情同意。选取已拔双侧前磨牙但因故未按时进行粘接托槽治疗的84例患者为研究对象。对患者的口腔上下颌模型进行三维扫描、重建和测量,根据患者的拔牙牙位（第一前磨牙或第二前磨牙）、颌骨类型（上颌或下颌）、垂直骨面型（均角、高角或低角）将其分为12组,应用多因素方差分析减数拔牙之后治疗中断1.5月情况下以下5项指标的变化,包括前牙拥挤度、尖牙间宽度、磨牙间宽度、拔牙间隙、前牙覆。结果 拔牙牙位、颌骨类型、垂直骨面型对减数拔牙后1.5个月拔牙间隙的减小量、前牙拥挤度的减小量有影响（P<0.001）,拔牙牙位和垂直骨面型对前牙覆增加量有影响（P<0.001）。拔除第一前磨牙的患者相对于拔除第二前磨牙的患者双侧邻牙的漂移明显（P<0.001）,上颌双侧邻牙漂移较下颌明显（P<0.001）,高角的患者较均角及低角的患者双侧邻牙漂移量明显（P<0.001）。结论 对于正畸患者,如果存在上颌减数、第一前磨牙减数、垂直骨面型为高角的情况,拔牙双侧...     

成人下颌第三磨牙与下前牙拥挤的相关性研究

[摘要] 目的 通过讲究成人下颌第三磨牙倾斜角及萌出间隙与下前牙不齐指数间的相关性,探讨下颌第三磨牙是否为导致下前牙拥挤的原因及下颌第三磨牙是否应在正畸治疗中拔除。方法 选择成人骨性Ⅰ类下颌前牙区拥挤的患者34例,在治疗前的下颌记存模型上测量下前牙不齐指数,在曲面断层片上测量下颌第三磨牙倾斜角及萌出间隙,分析下颌第三磨牙与下前牙拥挤的相关性。结果 下颌第三磨牙倾斜角及萌出间隙与下前牙不齐指数间无线性相关关系(P>0.05)。结论 不能证明下颌第三磨牙是下前牙拥挤的主要原因,应尽量避免预防性拔除没有临床症状的第三磨牙。     

Ⅱ类骨面型发育加速期拔与不拔牙颌骨变化的研究

目的 了解Ⅱ类骨面型患者于颈椎发育加速期行不拔与拔牙固定正畸治疗后颌骨及牙的变化情况。方法 24例Ⅱ类骨面型患者于颈椎发育加速期行固定正畸,治疗前、后摄头颅定位侧位X片,并对19项颌骨及牙的测量项目作分析。结果 ①24例患者治疗前、后上、下齿槽座点及颏前点下移,下颌升支、下颌体长、前后面高及前下面高增加,颌骨不调关系改善,下颌平面角未发生显著性变化。②治疗后两组仅下前牙倾斜度变化量差异有显著性,不拔牙组下前牙更唇倾,余测量项目的 变化量差异无显著性。结论 Ⅱ类骨面型错牙合患者颈椎发育加速期是开始固定正畸治疗的较好时机,拔牙与不拔牙治疗对Ⅱ类颌骨不调关系的改善效果未发现明显差别。     

A long-term evaluation of treated Class II division 2 malocclusions: a retrospective study model analysis.

Pre-treatment, end of treatment, and post-retention study models of 30 subjects with a Class II division 2 malocclusion were assessed, after a period of at least 3 years, in order to evaluate the long-term changes in occlusion, alignment, and arch dimensions. Molar relationship correction was found to be stable after retention. There were no variables which could be used to establish a prognosis of vertical stability. Over-correction of overbite was seen to relapse. Ten per cent of the cases showed unacceptable anterior maxillary irregularities after retention. Mandibular arch width and length usually showed a decrease after retention. An increase in lower intercanine width and arch length achieved by orthodontic treatment always relapsed. This relapse was associated with post-retention mandibular irregularity and crowding. Nine cases (30 per cent) showed an unacceptable degree of mandibular irregularity after retention. Pre-treatment crowding in the mandible showed a relationship with post-retention lower irregularity and crowding. There was a correlation between the number of years which had elapsed after retention, overbite relapse and post-retention mandibular irregularity.     

预防矫治后前牙旋转拥挤复发的临床研究

目的　评价改良嵴上纤维切断术(MSF)及邻面去釉接触区成形术(CPR)防止矫治后前牙旋转拥挤复发的有效性及可行性。方法　129例前牙旋转拥挤患者随机分为实验组和对照组。对照组81例仅作固定矫治;实验组 48例患者除作固定矫治外,其中23例行上下前牙MSF和CPR,余25例只作上下前牙MSF;术后3组均戴维持器1·8~ 2·3年。所有患者在安放固定矫治器前(T1期)、去除固定矫治器时(T2期)和去维持器后2·4年(T3期)各取牙模1副, 比较3组患者的不整齐指数(IRID)。结果　实验组拥挤旋转复发率平均低于对照组21·6%(P<0·001);实验组内:双因素组(MSF+CPR)下颌复发率较单因素组(MSF)低6·56%(P<0·05),但两组在防止上颌拥挤复发上无显著性差异 (P>0·05)。结论　MSF能较有效地防止矫治后前牙拥挤旋转复发,MSF配合CPR对维持下前牙矫治后的稳定具有显著效果。     

Stability and relapse of mandibular anterior alignment: University of Washington studies

For more than 40 years, research in the Department of Orthodontics, University of Washington (Seattle, WA) has focused on a growing collection of more than 800 sets of patient records to assess stability and relapse of orthodontic treatment. All patients had completed treatment a decade or more before the last set of data. Evaluation of treated premolar extraction patients, treated lower incisor extraction patients, treated non-extraction cases with generalized spacing, patients treated with arch enlargement strategies, and untreated normals showed similar physiologic changes: (1) Arch length decreases after orthodontic treatment. (2) Arch width measured across the mandibular canine teeth typically reduces posttreatment, whether or not the case was expanded during treatment. (3) Mandibular anterior crowding during the posttreatment phase is a continuing phenomenon well into the 20-to-40 years age bracket and likely beyond. (4) Third molar absence or presence, impacted or fully erupted, seems to have little effect on the occurrence or degree of relapse. (5) The degree of post-retention anterior crowding is both unpredictable and variable and no pretreatment variables either from clinical findings, casts, or cephalometric radiographs before or after treatment seem to be useful predictors.     

Stability and relapse of dental arch alignment

For more than 35 years, research in the Department of Orthodontics, University of Washington has focused on a growing collection of over 600 sets of patient records to assess stability and failure of orthodontic treatment. All had completed treatment a decade or more prior to the last set of data. Evaluation of treated premolar extraction cases, treated non-extraction cases with generalized spacing, cases treated by arch enlargement strategies, and untreated normal occlusions demonstrate similar physiological changes. 1. Arch length reduces following orthodontic treatment, but also does so in untreated normal occlusions. 2. Arch width measured across the mandibular canine teeth typically reduces post-treatment whether the case was expanded during treatment or not. 3. Mandibular anterior crowding during the post-treatment phase is a continuing phenomenon well into the 20-40 age bracket and likely beyond. 4. Third molar absence or presence, impacted or fully erupted, seems to have little effect on the occurrence or degree of relapse. 5. The degree of post-retention anterior crowding is both unpredictable and variable and no pretreatment variables either from clinical findings, casts, or cephalometric radiographs before or after treatment seem to be useful predictors.     

Postretention relapse of mandibular anterior crowding in patients treated without mandibular premolar extraction.

Treatment stability is one of the most important objectives in orthodontics, but, despite decades of research, it is still agreed that the stability of aligned teeth is variable and largely unpredictable. This study aimed to evaluate the relapse of mandibular anterior crowding in patients treated without mandibular premolar extraction. The sample comprised 40 patients of both sexes with Class I or II malocclusions who received nonextraction treatment in the mandibular arch with edgewise mechanics. Lateral cephalograms and dental casts of each patient were obtained at pretreament, posttreatment, and 5 years postretention. Relapse of mandibular anterior crowding was assessed, and associations between this relapse and other clinical factors were also investigated. Mandibular anterior crowding was measured by the Little irregularity index, and the data were evaluated by the Mann-Whitney test. The mean relapse of mandibular anterior crowding was 1.95 mm (26.54%) over the long term. No clinical factor studied was predictive of crowding relapse in the long term.     

Orthognathic treatment case after severe root resorption in the early treatment stage

This article presents an orthognathic treatment case after severe apical root resorption of maxillary anterior teeth using anterior segmental osteotomy.This case involved a 20-year-old female with the chief complaint of maxillary protruding and irregularly aligned mandibular anterior teeth. Her medical history showed no allergies or medical problems. The overbite was +3.0 mm, and the overjet +3.0 mm. After extraction of the four first premolars, a multi-bracket treatment was started. A severe root resorption of the maxillary anterior teeth was found 12 months after active treatment. The maxillary anterior segmental osteotomy was chosen as the compensatory treatment. The total treatment period was 2 years and 7 months. The post-retention panoramic radiograph showed no developmental root resorption.     

Rotational relapse of anterior teeth following orthodontic treatment and circumferential supracrestal fiberotomy

Background/purposeSeveral factors cause relapse of orthodontically de-rotated teeth after appliance removal. Circumferential supracrestal fiberotomy (CSF) may release the tension on the supra-alveolar fibers following tooth de-rotation, thereby reducing the relapse risk. However, careful identification of the amount and location of relapse enables proper clinical evaluation. We aimed to determine the amount of orthodontic relapse following CSF for de-rotated anterior teeth.Materials and methodsEleven patients with 90 orthodontically de-rotated anterior teeth were enrolled. CSF was performed after orthodontic treatment, during fixed retainer placement. Rotational correction and relapse were measured on three casts (preorthodontic treatment, cast 1; postorthodontic treatment + CSF, cast 2; and 12-month follow-up, cast 3). The Wilcoxon test was used to assess significant differences in the tooth rotation angles between casts 1 and 2 and casts 2 and 3. The relationship between the magnitude of relapse and pretreatment severity of rotation was assessed by the point biserial correlation test. The Mann-Whitney U test helped in identifying significant differences in the amount of relapse between maxillary and mandibular teeth.ResultsThe mean amount of rotational correction was 14.05°, while the mean amount and percentage of relapse were 1.1° and 10.8%, respectively [0.81° (8%) and 1.44° (14%) for maxillary and mandibular teeth, respectively]. The relapse amount was proportional to the pretreatment rotation severity, and it was larger for the mandibular canines. There was no significant difference in the amount of relapse between the maxillary and mandibular teeth (P = 0.07).ConclusionPost-treatment rotational relapse of anterior teeth subjected to CSF was minimal and statistically insignificant after 1 year of follow-up. This validates the promising results of CSF when combined with appropriate mechanical retention for an adequate period.     

Long term stability of treatment outcome after fixed orthodontic treatment with or without premolar extraction

Purpose

To evaluate and compare the long term stability of treatment outcome in patients treated with fixed orthodontic treatment with and without premolar extractions.

Orthodontic relapse, apical root resorption, and crestal alveolar bone levels

This investigation examined the relationship of postorthodontic treatment relapse to crestal alveolar bone support and root resorption. Thirty-six persons having completed the retention phase of orthodontics at least 10 years earlier were divided into two groups based on the amount of relapse crowding of the mandibular anterior teeth. Eighteen subjects (relapse group) exhibited 2 mm or more of mandibular anterior relapse crowding and 18 subjects (nonrelapse group) exhibited no mandibular anterior relapse crowding. At time of recall, full-mouth series of periapical and bitewing radiographs were obtained as well as lateral cephalometric films to allow comparison with similar lateral cephalometric films obtained at pretreatment and retention time points. The radiographs were examined to assess three parameters: root resorption, crestal alveolar bone levels, and changes in the position and angulation of the maxillary incisors. The subjects in the relapse group had undergone longer periods of treatment and exhibited a greater prevalence of root resorption; they also displayed significantly greater crestal alveolar bone level distances, indicating greater loss of bone support than that observed in the nonrelapse group. The distances that teeth were translated seemed to affect the extent of root resorption and crestal bone loss with smaller amounts of tooth translation seemingly more prone to demonstrate tissue loss. The findings of this investigation suggest there may be a relationship between orthodontic relapse and the parameters of increased root resorption and decreased crestal alveolar bone levels.     

Repair and revision 8. Relapse of lower incisors: retreatment?

Research into the long-term stability of orthodontic treatment at the University of Nijmegen (the Netherlands) until 10 years after retention has shown that nearly 50% of the total relapse takes place the first two years after retention. After that period certain stability is reached except for the lower front teeth. Ten years after the retention phase their position is even worse than at the start of treatment. The changes in lower front teeth alignment are the result of relapse, but also of normal physiological changes during ageing of the dentition. Therefore it is questionable whether late mandibular incisor irregularity should be (re)treated. Relapse of mandibular incisor alignment shortly after debonding can be restored by tightly tying the rotated incisor(s) to the C-C bar with a steel ligature, by using a spring-retainer or by rebonding of brackets to the lower front teeth. After correction of the incisor position the C-C bar should be bonded to all lower front teeth. (Re)treatment of mandibular incisor irregularity at an older age asks for more complicated treatment mechanics.