Intraosseous screw-supported upper molar distalization

The aims of the present study were to investigate (1) the efficiency of intraosseous screws for anchorage in maxillary molar distalization and (2) the sagittal and vertical skeletal, dental, and soft tissue changes after maxillary molar distalization using intraosseous screw-supported anchorage. Twenty-five subjects (18 girls and seven boys; 11.3 to 16.5 years of age) with skeletal Class I, dental Class II malocclusion participated in the study. An anchorage unit was prepared for molar distalization by placing an intraosseous screw behind the incisive canal at a safe distance from the midpalatal suture following the palatal anatomy. The screws were placed and immediately loaded to distalize upper first molars or the second molars when they were present. The average distalization time to achieve an overcorrected Class I molar relationship was 4.6 months. The skeletal and dental changes were measured on cephalograms and dental casts obtained before and after the distalization. In the cephalograms, the upper first molars were tipped 8.8 degrees and moved 3.9 mm distally on average. On the dental casts, the mean distalization was five mm. The upper molars were rotated distopalatally. Mild protrusion (mean 0.5 mm) of the upper central incisors was also recorded. However, there was no change in overjet, overbite, or mandibular plane angle measurements. In conclusion, immediately loaded intraosseous screw-supported anchorage unit was successful in achieving sufficient molar distalization without major anchorage loss.     

Maxillary molar distalization with a bone-anchored pendulum appliance

To obtain an effective and compliance-free molar distalization without an anchorage loss, we designed the bone-anchored pendulum appliance (BAPA). The aim of this study was to evaluate the stability of the anchoring screw, distalization of the maxillary molars, and the movement of teeth anterior to maxillary first molars. The study group comprised 10 patients (mean age 13.5 +/- 1.8 years) with Class II molar relationship. A conventional pendulum appliance was modified to obtain anchorage from an intraosseous screw instead of the premolars. The screw was placed in the anterior paramedian region of the median palatal suture. Skeletal and dental changes were measured on cephalograms, and dental casts were obtained before and after distalization. A super Class I molar relationship was achieved in a mean period of 7.0 +/- 1.8 months. The maxillary first molars distalized an average of 6.4 +/- 1.3 mm in the region of the dental crown by tipping distally an average of 10.9 degrees +/- 2.8 degrees . Also, the maxillary second premolar and first premolar moved distally an average of 5.4 +/- 1.3 mm and 3.8 +/- 1.1 mm, respectively. The premolars tipped significantly distally. No anterior incisor movement was detected. The BAPA was found to be an effective, minimally invasive, and compliance-free intraoral distalization appliance for achieving both molar and premolar distalization without any anchorage loss.     

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??Objective??To evaluate the treatment effects of maxillary dentition distalization using orthodontic miniscrews placed in different insertion sites and to provide a clinical guidance in choosing the most efficient site of maxillary dentition disatalization. Methods??Twenty-four female patients were selected from January 2014 to June 2017 at Department of Orthodontics??Dalian Stomatological Hospital??the age of all patients in our study ranging from 21 to 26 years old??who presented with dental and skeletal class ?? malocclusion. We divided the samples into three groups??Group A??miniscrews were placed in the region between the second premolar and the first molar??Group B??miniscrews were inserted in the infrazygomaticcrest site?? Group C??miniscrews were inserted and inclined  in the the buccal region of the maxillary second molars. Measurements were performed on the lateral cephalometric radiogragh at two time points??the first was before the orthodontic treatment??and the second was at 4 months after distalization of maxillar dentition. Results??Four months after distalization of the maxillary dentition we found that in group A the molar was obviously distally inclined??the inclination angle of the upper first molar toward distal??MTD??was 2.28° ± 1.4°. In group B??the upper incisors and first molar were intruded??the distance from the incisal edge of the maxillary central incisor to the X axis??U1-X??was decreased??1.0 ± 0.9??mm??the distance from the mesial proximal contact area of maxillary first molar’mesial surface to the X axis??U6-X??was decreased??1.4 ± 0.7??mm. In group C??the upper incisors were retracted obviously??the distance from the incisal edge of the maxillary central incisor to the Y axis??U1-Y??was decreased??2.0 ± 1.8??mm??and the distance from the mesial proximal contact area of maxillary first molar’mesial surface to the Y axis??U6′-Y??was decreased??2.6 ± 1.2??mm??the difference being statistical ??all P < 0.05??. Conclusion??Orthodontic miniscrews placed in different insertion sites all can make maxillary dentition distalization. The molar was obviously distally inclined in group A. The upper incisors and first molar were intruded in group B. The efficiency of maxillary dentition distalization was the highest in group C.     

不同部位植入种植钉远中移动上颌牙列的临床效果研究

目的　对比不同部位植入种植钉远中移动上颌牙列的治疗效果,为临床有效应用种植钉远中移动骨性Ⅱ类错牙合的上颌牙列提供参考。方法　选取2014年1月至2017年6月就诊于大连医科大学附属大连市口腔医院正畸科的骨性Ⅱ类错牙合成年女性患者24例。年龄21 ~ 26岁,平均（23.8 ± 1.2）岁。按种植钉的植入部位平均分为3组：A组,将种植钉植入上颌第二前磨牙和第一磨牙牙根之间;B组,将种植钉植入颧牙槽嵴区;C组,将种植钉植入第二磨牙颊侧骨皮质区。对所有患者治疗前和种植钉施力4个月后的头颅定位侧位片进行测量分析,观察各组上颌牙列远中移动的临床效果和特征。结果　各组患者种植钉施力4个月后较治疗前,上颌磨牙远中移动明显（均P < 0.05）。其中A组患者上颌第一磨牙远中倾斜最为明显,上颌第一磨牙远中倾斜角度（MTD）为2.28° ± 0.14°;B组患者上颌切牙及上颌磨牙明显压低,上颌中切牙切缘到X轴的距离（U1-X）减小（1.0 ± 0.9）mm,上颌第一磨牙牙冠近中面最突点到X轴的距离（U6-X）减小（1.4 ± 0.7）mm;C组患者上颌牙列远中移动最为明显,上颌中切牙切缘到Y轴的距离（U1-Y）减小（2.0 ± 0.8）mm;上颌第一磨牙牙冠近中面最突点到Y轴的距离（U6′-Y）减小（2.6 ± 1.2）mm;其差异均具有统计学意义（均P < 0.05）。结论　不同部位植入种植钉均可远中移动上颌牙列,在上颌第二前磨牙和第一磨牙牙根之间植入种植钉时,上颌第一磨牙产生明显远中倾斜移动;在颧牙槽嵴区植入种植钉时,对上颌切牙及磨牙产生压低作用;在上颌第二磨牙颊侧骨皮质区植入种植钉时,远移上颌牙列的效率最高。     

Short-term treatment effects of quad-helix on maxillomandibular expansion in patients with maxillary incisor crowding

The purpose of this study was to evaluate the effects of the maxillary arch expansion on maxillomandibular arch widths in patients treated with the quad-helix versus untreated controls. The treatment group consisted of 50 consecutive patients treated for maxillary incisor crowding with a quad-helix appliance in the early mixed dentition. Lateral cephalograms and dental casts taken at the start (T0) and end (T1) of the quad-helix treatment were obtained. The control group consisted of 50 untreated patients with the same type of malocclusion. Two consecutive lateral cephalograms and dental casts of each untreated patient were taken at about the same time as T0 and T1. All these study materials were analyzed for comparison between the two groups. The mean ages at T0 and T1 in the two groups were about the same. The maxillary first molars moved and tipped distally in the treatment group and mesially in the control group. The quad-helix treatment actually expanded the mandibular and maxillary arches concurrently. The more the maxillary arch widths were expanded and the less the maxillary first molars were inclined distally, the more the mandibular arch widths were expanded. The quad-helix activation caused lingual tipping and mesiobuccal rotation of the maxillary first molars. The mesiobuccal rotation of the maxillary first molars could turn molar occlusal relationships for the better from Class II to Class I. The quad-helix treatment gives rise to spontaneous expansion of the mandibular arch concurrent with maxillary expansion in the early mixed dentition patients with maxillary incisor crowding.     

Evaluation of maxillary molar distalization with the distal jet: a comparison with other contemporary methods

Maxillary molar distalization is an increasingly popular option for the resolution of Class II malocclusions. This communication describes the effects of one particular molar distalizing appliance, the distal jet, in a sample of 20 consecutively treated and growing subjects (11 females, nine males; mean starting age of 13) and compares these effects with those of similar devices. Pre- and postdistalization cephalometric radiographs and dental models were analyzed to determine the dental and skeletal effects. The distal jet appliances were constructed using a biomechanical couple to direct the distalizing force to the level of the maxillary first molar's center of resistance. The distal jet was the only appliance used during the distalization phase of treatment. Examination of the cephalometric tracings demonstrated that the crowns of the maxillary first molars were distalized an average of 3.2 mm into a Class I molar relationship. In the process, the first molars were tipped distally an average of 3.1 degrees, however, the amount of tipping in each case was influenced by the state of eruption of the second molar. In subjects whose second molars had erupted only to the level of the apical third of the first molar roots, distal tipping was almost twice that seen when the second molar had completed their eruption. Anchorage loss measured at the first premolars averaged 1.3 mm, but the crowns tipped 3.1 degrees distally because of the design of the appliance. The maxillary incisors were proclined an average of 0.6 degrees with minimal effect on the mandibular plane angle and lower facial height. This study suggests that the distal jet appliance effectively moves the maxillary molars distally into a Class I molar relationship with minimal distal tipping, however, some loss of anchorage is to be expected during this process. The distal jet appliance compares favorably with other intraoral distalization devices and with mechanics featuring mandibular protraction for the resolution of patients with Class II, despite the fact that these types of mechanics address different jaws.     

上颌第二磨牙萌出对“摆”式矫治器远中移动上颌磨牙疗效的影响

目的研究上颌第二磨牙不同萌出阶段对”摆”式矫治器远中移动上颌磨牙疗效的影响。方法选择上颌牙列轻中度拥挤，磨牙远中关系的病例25例。根据上颌第二磨牙萌出情况分为未萌组（15例）和萌出组（10例）。采用“摆”式矫治器远中移动上颌磨牙。以X线头影测量分析为测定手段。结果①两组的磨牙远中移动距离无显著差异。②未萌组的上颌第一磨牙远中倾斜要大于萌出组，但未萌组的上颌第二磨牙远中倾斜要小于萌出组。③萌出组的上颌第一磨牙相对伸长较多。④上颌中切牙唇向倾斜移动量和前牙覆盖增加量在萌出组较大。结论①萌出的上颌第二磨牙对上颌磨牙远中移动无明显影响。②上颌第二磨牙萌出与否对磨牙远中倾斜有较大影响。③萌出的上颌第二磨牙造成较多支抗丧失。④上颌第二磨牙萌出者在治疗后其上颌第一磨牙伸长较多。     

Distal movement of mandibular molars in adult patients with the skeletal anchorage system.

The skeletal anchorage system (SAS) consists of titanium anchor plates and monocortical screws that are temporarily placed in either the maxilla or the mandible, or in both, as absolute orthodontic anchorage units. Distalization of the molars has been one of the most difficult biomechanical problems in traditional orthodontics, particularly in adults and in the mandible. However, it has now become possible to move molars distally with the SAS to correct anterior crossbites, maxillary dental protrusion, crowding, and dental asymmetries without having to extract premolars. This study evaluated the treatment and posttreatment changes during and after distalization of the mandibular molars. In 15 adult patients (12 women and 3 men), a total of 29 mandibular molars were successfully distalized with SAS. The amount of distalization and relapse and the type of tooth movement were analyzed with cephalometric radiographs and dental casts. The average amount of distalization of the mandibular first molars was 3.5 mm at the crown level and 1.8 mm at the root level. The average amount of relapse was 0.3 mm at both the crown and root apex levels. Of 29 mandibular molars, 9 were tipped back, and the others were translated distally in accordance with the established treatment goals. SAS is a viable modality to move mandibular molars for distally correcting anterior crossbites, malocclusions characterized by mandibular anterior crowding, and dental asymmetries.     

利用种植体支抗远移下颌磨牙的效果评价

目的：研究安氏Ⅲ类错患者中,采用微型种植体作支抗,远移下颌磨牙的临床效果及其作用特点。方法：选择16例成人患者,将32枚微型种植体植于下颌第二前磨牙与第一磨牙之间颊侧牙槽骨内,Ni-Ti螺旋弹簧压缩后置于下颌第一前磨牙与下颌第一磨牙之间,推磨牙远移。通过测量下颌第一磨牙在近远中方向、垂直向的位置变化,以衡量磨牙的位置改变。并通过下颌中切牙的位置变化,评价支抗强弱。结果：下颌第一磨牙平均远中移动4.5mm,疗程5.4个月,平均移动速度0.8mm/月;磨牙长轴向远中倾斜角度为3.9°。下颌中切牙位置基本无改变。结论：所有下颌磨牙被远移到了恰当的位置。未见前牙支抗丧失。种植体作支抗推下颌磨牙远移的过程中,发挥了强支抗的作用。临床操作较方便,是一种值得推广的方法。     

Dentoalveolar and skeletal changes associated with the pendulum appliance.

The purpose of the study was to examine the dentoalveolar and skeletal effects of the pendulum appliance in Class II patients at varying stages of dental development and with varying facial patterns (high, neutral, and low mandibular plane angles). Specifically, the amount and nature of the "distalization" of the maxillary first molars and the reciprocal effects on the anchoring maxillary first premolars and incisors were studied, as were skeletal changes in the sagittal and vertical dimensions of the face. Pretreatment and posttreatment cephalometric radiographs obtained from 13 practitioners were used to document the treatment of 101 patients (45 boys and 56 girls). The average maxillary first molar distalization was 5.7 mm, with a distal tipping of 10.6 degrees. The anchoring anterior teeth moved mesially, as indicated by the 1.8-mm anterior movement of the upper first premolars, with a mesial tipping of 1.5 degrees. The maxillary first molars intruded 0.7 mm, and the first premolars extruded 1.0 mm. Lower anterior facial height increased 2.2 mm; there was no significant difference in lower anterior facial height increase between patients of high, neutral, or low mandibular plane angles. In patients with erupted maxillary second molars, there was a slightly greater increase in lower anterior face height and in the mandibular plane angle and a slightly greater decrease in overbite in comparison to patients with unerupted second molars. Similar findings were observed in patients with second premolar anchorage versus those with second deciduous molar anchorage. The results of this study suggest that the pendulum appliance is effective in moving maxillary molars posteriorly during orthodontic treatment. For maximum maxillary first molar distalization with minimal increase in lower anterior facial height, this appliance is used most effectively in patients with deciduous maxillary second molars for anchorage and unerupted permanent maxillary second molars, although significant bite opening was not a concern in any patient in this study.     

改良式摆型矫治器远中移动上颌磨牙的疗效分析

目的 评价改良式摆型矫治器远中移动上颌磨牙的疗效。方法 选择14例牙性安氏Ⅱ类错的患者,应用改良式摆型矫治器远移上颌第一磨牙,通过矫治前和磨牙远移到位后的X线头影测量分析评价其疗效。结果 磨牙平均向远中移动3.85mm,牙冠远中倾斜3.22°;切牙近中倾斜移动2.08mm,覆盖增加1.68mm。结论 改良式摆型矫治器能有效地整体远中移动上颌磨牙,快速矫正磨牙关系,但也会引起少量的支抗丧失和切牙唇向移动。     

Effects of a segmented removable appliance in molar distalization

The aim of the present investigation was to evaluate the skeletal and dentoalveolar treatment effects of a segmented removable appliance [removable molar distalizer (RMD)] for molar distalization. The study was conducted on 28 patients (12 females and 16 males), with a mean age of 11.8 years. All presented with a skeletal Class I malocclusion and a bilateral dental Class II molar relationship. The pre- and post-distalization records included lateral head films, study models and standard photographs. The findings were evaluated with a paired samples t-test. The average maxillary first molar distalization with the RMD was 3.98 mm, with 4.61 degrees of distal tipping. The maxillary second premolars drifted distally 2.13 mm on average with 1.54 degrees of distal tipping, while the maxillary first premolars showed 1.23 mm of mesial movement and 1.98 degrees of mesial tipping. The incisors protruded 1.09 mm with 1.27 degrees of labial tipping. The RMD was effective in distal molar movement and all patients attained a bilateral Class I molar relationship in an average period of 4.5 months. Hygiene problems and mucosal irritations, frequently found with fixed intraoral distalization techniques, were not observed during the distalization period.     

两步法单侧整体推磨牙向后方法临床研究

目的介绍两步单侧整体推磨牙向后的方法，并探讨先倾斜、后竖直的矫治理念在推磨牙向后领域的应用。方法选取单侧磨牙远中关系伴同侧牙列中度拥挤的患者12例，男4例，女8例，年龄10-12岁。采用“先倾斜、后竖直”两步推单侧磨牙向远中，矫正Ⅱ类磨牙关系。磨牙颊沟处粘结一条3．5mm长的不锈钢圆丝作为在X线片上观测磨牙运动的标记线。治疗前、后取研究模型、拍摄头颅侧位定位片和全景片并进行测量分析，对测量结果进行配对资料的t检验。结果所有矫治磨牙均达到中性关系，磨牙平均每月远中移动（1．10±0．75）mm，远中倾斜移动阶段平均需要（4．75±1.85）月，磨牙竖直阶段平均（3．56±0．90）月，治疗前后磨牙倾斜角度以及前牙倾斜角度的差异均无统计学意义（P〉0．05）。结论两步法推磨牙向后可以使磨牙达到完全整体后移的效果，且无明显前牙支抗丧失。     

Unilateral molar distalization with a modified slider

Although there are numerous publications on bilateral non-compliance molar distalization appliances, there is limited information on problems such as asymmetrical unilateral Class II malocclusions. The aim of the present investigation was to examine the distalization of molars unilaterally in patients with a unilateral Class II molar relationship utilizing a Keles Slider, designed without a bite plane. Ten girls (mean age 13.94 +/- 2.13 years) and seven boys (mean age 13.12 +/- 1.51 years) comprised the study material. Following insertion of the appliance, the patients were seen monthly and the screw was reactivated every 2 months. After a super-Class I molar relationship was achieved, the appliance was removed and the molars were stabilized with a Nance appliance for 2 months before the second-phase of orthodontic treatment. The Nance appliance was maintained in the palate until the end of canine distalization. Lateral cephalometric radiographs were obtained before and immediately after insertion of the molar distalizer. The results showed that the maxillary first molars were distalized bodily on average by 2.85 mm. The maxillary first premolars moved forward bodily 2 mm and were extruded 2.03 mm. In all, 1.32 mm of protrusion, 1.12 mm of extrusion, and 1.79 degrees of proclination of the upper incisors were observed. The mandibular incisors and mandibular molars erupted 0.83 and 0.95 mm, respectively. The unilateral Keles Slider distalized molars successfully to a Class I molar relationship.     

Efficiency of noncompliance simultaneous first and second upper molar distalization: a three-dimensional tooth movement analysis

Objective of this prospective study was the three-dimensional (3D) analysis of tooth movements after the noncompliance simultaneous distalization of the first and second maxillary molars. Ten patients (five girls and five boys; mean age: 13.2 years) with bilateral Class II molar relationships were treated with a noncompliance, fixed intraoral appliance. Upper second molars had already erupted in all cases. Dental casts and lateral cephalometric radiographs were taken immediately before placement and after removal of the appliance. The casts were 3D digitized and superimposed on a predefined area in the palate. The resulting holograms, as well as the cephalometric radiographs, were digitized and analyzed by means of customized cephalometric software. The whole procedure was repeated after a two- to four-week interval to estimate the error of both methods. The cast assessment of 3D sagittal and vertical tooth movements was more reliable than the cephalometric record. The average maxillary first molar distal movement was 2.8 mm. Anchorage loss was expressed by a 1.9-mm proclination of the central incisors. A substantial variation among patients and among the right and left side in the same patient was observed. Noncompliance simultaneous distalization of the first and second maxillary molars can be an efficient treatment option for the correction of Class II molar relationship. However, anchorage loss and individual variation have to be seriously considered. Bilaterally symmetrical effectiveness should not be relied upon.     

安氏Ⅱ类1分类拔牙病例正畸治疗后后牙关系的稳定性研究

目的　探讨安氏Ⅱ类1分类患者正畸治疗前、后后牙关系的变化趋势,分析可能影响后牙关系复发的因素。方法　选取采用拔牙治疗的安氏Ⅱ类1分类患者29例,其中男12例,女17例。根据ANB角进一步分为牙性Ⅱ类14例,骨性Ⅱ类15例。分别对其正畸治疗前、后进行模型测量和X线头影测量。结果　所有患者的Ⅱ类磨牙关系在治疗后均得到明显改善,随访时仅有少量复发。牙性Ⅱ类患者治疗后下磨牙近中移动量(4·52±2·15) mm,大于上磨牙移动量(3·62±2·62)mm,而骨性Ⅱ类患者上下磨牙近中移动量相似,但ANB角由治疗前的(6·27± 1·08)°明显减小为(4·64±1·17)°。随访时两类错患者上下颌磨牙均近中移动,且上颌磨牙移动量大于下颌磨牙。多元回归分析提示下颌骨水平向生长和上前牙不齐指数与磨牙关系复发有关。结论　Ⅱ类错患者正畸治疗后磨牙关系较为稳定。牙性Ⅱ类错磨牙关系的解除有赖于上下颌磨牙相对移动调整,骨性Ⅱ类错则依靠上下颌骨间位置关系的改变。有利的下颌生长型和上颌前牙不齐程度等与磨牙关系的保持有密切关系。     

Posttreatment evaluation of the distal jet appliance.

This study analyzed molar distalization with the distal jet appliance, its effect on the anchor teeth, and the outcome at the completion of orthodontic treatment. Pretreatment, after distalization, and posttreatment lateral cephalometric radiographs were evaluated for 21 adolescent girls and 12 adolescent boys. The mean age of the subjects at the time of the pretreatment radiograph was 12.8 +/- 2.2 years. The mean time for the correction of the Class II molar relationship was 6.7 +/- 1.7 months, and the mean total treatment time was 25.7 +/- 3.9 months. The results of this study showed that the distal jet appliance distalized the maxillary molars, but there was significant loss of anchorage. The distal jet also showed less tipping of the maxillary molars and better bodily movement of molars because the force was applied closer to the center of resistance. The observations of treatment outcome indicate that the 1.8-mm mean net anterior movement of the maxillary first molar was more than offset by the 4.8-mm mesial movement of the mandibular first molar. There was no significant increase in lower face height. Consequently the effect on the facial balance was negligible.     

Mini-implants for en masse intrusion of maxillary anterior teeth in a severe Class II division 2 malocclusion

This case report describes the treatment of a 16-year-old post pubertal male patient with a severe Class II division 2 malocclusion and 100% deep bite. In the first phase of treatment, a 'Jones-Jig' molar distalization appliance was used to distalize the maxillary molars by more than 6 mm, to achieve a Class I molar relation. In the second phase of treatment, mini-implants were inserted between the roots of the maxillary lateral incisor and canine to intrude all the maxillary anterior teeth en masse in a single step. Four millimetres of intrusion was achieved. The implants remained stable throughout treatment. In the mandibular arch the incisors were proclined to alleviate the severe crowding. Good overjet and overbite was achieved and has been maintained one year after completion of active orthodontic treatment.     

无托槽隐形矫治技术推磨牙向远中牙齿移动类型的研究

目的研究无托槽隐形矫治技术推磨牙向远中牙齿移动的类型。方法选取2016年3月至2018年10月于首都医科大学附属北京口腔医院正畸科就诊的患者58例,所有患者均采用无托槽隐形矫治技术推磨牙向远中。治疗前后均拍摄头颅侧位片及曲面体层片,分别测量上下颌第一、二磨牙远移量及牙长轴倾斜度。结果治疗前后上下颌第一、二磨牙到翼肌垂直平面(PTV)的距离比较,差异均有统计学意义(均P<0.05);治疗后上颌第一磨牙向远中移动(1.28±1.24)mm,上颌第二磨牙向远中移动(2.47±1.77)mm,下颌第一磨牙向远中移动(1.77±1.20)mm,下颌第二磨牙向远中移动(2.83±1.39)mm。治疗前后曲面体层片中的上下颌第一、二磨牙牙长轴与双侧眶下缘基准平面所成角比较,差异均无统计学意义(均P>0.05)。治疗前后头颅侧位片中上颌磨牙与前颅底平面(SN平面)所成角及下颌磨牙与下颌平面(MP平面)所成角比较,差异均无统计学意义(均P>0.05)。结论本研究初步证实了无托槽隐形矫治技术推磨牙向远中时磨牙是整体移动的,而非倾斜移动。     

摆形矫治器与直丝弓矫治器治疗安氏Ⅱ类骨性Ⅰ类错畸形的研究

目的　分析安氏Ⅱ类骨性Ⅰ类错畸形患者经摆形矫治器结合直丝弓矫治器治疗后的牙颌面形态变化, 探讨此方法建立正常牙关系的机制。方法　10例接受摆形矫治器结合直丝弓矫治器治疗的安氏Ⅱ类骨性Ⅰ类 错患者,分别在治疗前(T1阶段)、摆形矫治器治疗后(T2阶段)及直丝弓矫治结束后(T3阶段)拍摄头颅定位侧位 片,对3个阶段牙齿、颌骨及软组织的位置变化进行测量及分析,同时观察上颌第二、三磨牙的位置和萌出情况。 结果　摆形矫治器治疗阶段上颌第一、二磨牙远中整体移动并适度远中倾斜,上切牙唇向倾斜,上齿槽座点前移; 直丝弓矫治后上颌第一、二磨牙位置与治疗前无明显差异,下齿槽座点和下颌第一磨牙明显前移;上颌第二磨牙萌 出顺利。结论　摆形矫治器可使上磨牙明显远中移动,但固定矫治结束后上磨牙前后位置因上颌骨生长和一定程 度的支抗丧失而有所复原;Ⅰ类磨牙关系的建立可能是上下磨牙差别移动和颌骨差别生长的综合结果。