Long-term stability of miniscrew anchored maxillary molar distalization in Class II treatment

ObjectiveTo investigate treatment stability of miniscrew-anchored maxillary distalization in Class II malocclusion.Materials and MethodsThis retrospective study included a distalization (n = 19) and a control (n = 19) group; a patient group with minor corrections served the control. Lateral cephalograms of 38 adult patients were taken before (T0), immediately after (T1), and 3–4 years after (T2) treatment. Horizontal and vertical movement and tipping of the maxillary first molars (U6) and central incisors (U1) were measured along with skeletal craniofacial parameters at three time points to compare the two groups regarding the achieved treatment effects and their stability.ResultsTotal arch distalization therapy led to 4.2 mm of distal movement of U6 without distal crown tipping (0.6° of axis change) and 3.3° of occlusal plane steepening. Over an average retention period of 42 months, maxillary total arch distalization provided high stability of treatment results, showing the same amount of mesial movement (0.7 mm) as the control group.ConclusionsIn Class II treatment, miniscrew-anchored maxillary total arch distalization can provide stable distal movement of the maxillary first molars and central incisors.     

摆形矫治器远移磨牙的矢状方向分析

目的本研究在矢状方向上分析摆形矫治器远移上磨牙的效果及对支抗前磨牙、切牙的交互作用。方法选择14例安氏Ⅱ类错、上牙弓I-Ⅱ°拥挤患者,应用摆形矫治器远移上颌第一磨牙,每一病例治疗前后进行头影测量分析比较。结果14例患者在17.5±7周内上第一磨牙远移3.18±1.62mm,伴有前磨牙1.42±1.16mm、切牙0.97±0.45mm的近中移动,同时注意到上磨牙的远移、第二前磨牙与切牙的近移均是倾斜移动,统计分析显示各评估对象在治疗前后具有显著性差异。结论摆形矫治器是一种简便、对患者依赖少的上磨牙远移装置,可在临床中广泛应用。     

远移上颌磨牙后颌面部垂直关系变化机制的研究

目的：探讨远移,E颌磨牙后[牙合]、颌面垂直关系的变化及其作用机制。方法：回顾性研究远移上颌磨牙的牙性Ⅱ类错[牙合]病例88例（女48例,男40例）,比较矫治前后的头颅定位侧位X线片中反映[牙合]、颌面垂直关系的5项观察指标,对有变化的垂直关系指标与可能机制进行相关性分析。结果：88例患者矫治后前牙覆[牙合]明显减小（P〈0．01）,[牙合]平面角、下颌平面角及下前面高均有增加（P〈0．05）,腭平面角改变无统计学意义。上下中切牙的唇倾度、上颌第一磨牙与髁突距离、上颌第一磨牙近颊尖与腭平面距离分别与上述4项指标呈一定的相关关系。结论：远移上颌磨牙会一定程度增加患者[牙合]、颌面垂直距离,尤其表现在前牙覆[牙合]明显减小。凡影响上下中切牙的唇倾度、上颌第一磨牙与髁突的距离、上颌第一磨牙近颊尖与腭平面距离的因素均可影响磨牙远移后患者的[牙合]、颌面垂直关系。     

远移上颌磨牙对(牙合)、颌面垂直关系改变的初步研究

目的:探讨远移上颌磨牙是否对患者(牙合)、颌面垂直关系产生变化及其相关因素.方法:回顾性研究远移上颌磨牙的牙性Ⅱ类错(牙合)病例88例(女48例,男40例),比较其矫治前后的X线头颅定位侧位片中反应(牙合)、颌面垂直关系的5项观察指标.结果:88例矫治后前牙覆(牙合)明显减小(2.86±2.69 mm),腭平面角改变无统计学意义(0.21°±3.54°),(牙合)平面角、下颌平面角及患者的下前面高均有少量增加(0.91°±3.37°,1.29°±4.66°,1.05±3.82 mm).高中低角患者的这5项观察值不存在统计学差别;上颌第二磨牙萌出与否、以及支抗的种类对远移磨牙产生的垂直关系改变有一定影响,但作用较小.结论:远移上颌磨牙会一定程度的减小患者前牙覆(牙合),但就整个颌面垂直关系而言变化较小.提示远移上颌磨牙产生垂直向变化可能存在其它原因.     

钟摆矫治器联合颊侧推簧远移磨牙的疗效分析

目的：评价钟摆矫治器联合颊侧推簧远移磨牙的疗效.方法：选择40例牙性安氏Ⅱ类错（牙合）畸形的患者,随机均分为两组：钟摆矫治器联合颊侧推簧远移磨牙组（组1）和头帽口外弓远移磨牙组（组2）,在治疗开始前（T0）和远移磨牙完成时（T1）分别拍摄侧位头影定位片进行头影测量,t检验分析组内和组间的差异.结果：组1和组2远移磨牙的平均距离分别是（4.48±1.63） mm、（2.68±1.71） mm;组1和组2磨牙远中倾斜的平均角度分别是5.46°±3.23°、1.02°±2.16°;组1上颌中切牙未发生明显的唇倾和唇向移位,而组2上颌中切牙发生了较为明显的腭侧移位.结论：钟摆矫治器联合颊侧推簧远移磨牙可有效防止前牙支抗的丧失、控制磨牙的近中颊侧旋转.     

远移上颌磨牙对、颌面垂直关系改变的初步研究

目的:探讨远移上颌磨牙是否对患者牙合、颌面垂直关系产生变化及其相关因素。方法:回顾性研究远移上颌磨牙的牙性Ⅱ类错牙合病例88例(女48例,男40例),比较其矫治前后的X线头颅定位侧位片中反应牙合、颌面垂直关系的5项观察指标。结果:88例矫治后前牙覆牙合明显减小(2.86±2.69 mm),腭平面角改变无统计学意义(0.21°±3.54°),牙合平面角、下颌平面角及患者的下前面高均有少量增加(0.91°±3.37°,1.29°±4.66°,1.05±3.82 mm)。高中低角患者的这5项观察值不存在统计学差别;上颌第二磨牙萌出与否、以及支抗的种类对远移磨牙产生的垂直关系改变有一定影响,但作用较小。结论:远移上颌磨牙会一定程度的减小患者前牙覆牙合,但就整个颌面垂直关系而言变化较小。提示远移上颌磨牙产生垂直向变化可能存在其它原因。     

Comparative evaluation of molar distalization therapy with erupted second molar: Segmented versus Quad Pendulum appliance

Background

There are controversial opinions about the effect of erupted second molars on distalization of the first molars. Most of the distalizing devices are anchored on the first molars, without including second molars; so, differences between sequentially distalize maxillary molars (second molar followed by the first molar) or distalize second and first molars together are not clear. The aim of the study was to compare sequential versus simultaneous molar distalization therapy with erupted second molar using two different modified Pendulum appliances followed by fixed appliances.

Methods

The treatment sample consisted of 35 class II malocclusion subjects, divided in two groups: group 1 consisted of 24 patients (13 males and 11 females) with a mean pre-treatment age of 12.9 years, treated with the Segmented Pendulum (SP) and fixed appliances; group 2 consisted of 11 patients (6 males and 5 females) with a mean pre-treatment age of 13.2 years, treated with the Quad Pendulum (QP) and fixed appliances. Lateral cephalograms were obtained before treatment (T1), at the end of distalization (T2), and at the end of orthodontic fixed appliance therapy (T3). A Student t test was used to identify significant between-group differences between T1 to T2, T2 to T3, and T1 to T3.

Results

QP and SP were equally effective in distalizing maxillary molars (3.5 and 4 mm, respectively) between T1 and T2; however, the maxillary first molar showed less distal tipping (4.6° vs. 9.6°) and more extrusion (1.1 vs. 0.2 mm) in the QP group than in the SP group, as well as the vertical facial dimension, which increased more in the QP group (1.2°) than in the SP group (0.7°). At T3, the QP group maintained greater increase in lower anterior facial height and molar extrusion and decrease in overbite than the SP group.

Conclusion

Quad Pendulum seems to have greater increase in vertical dimension and molar extrusion than the Segmented Pendulum.     

Total arch maxillary distalization using infrazygomatic crest miniscrews in the treatment of Class II malocclusion: a prospective study

ObjectivesTo evaluate treatment effects in Class II patients using infrazygomatic crest (IZC) miniscrews (MS).Materials and MethodsA prospective sample of 25 adolescents (14 females and 11 males; mean age: 13.6 ± 1.5 years) who underwent maxillary dentition distalization treatment with IZC MSs were recruited. Lateral cephalograms and digital models at the beginning of treatment (T1) and after Class II molar correction (T2) were obtained. To compare cephalometric and digital model changes, paired t-test and Wilcoxon test were used. A significance level of 5% was used.ResultsAll patients achieved Class II molar correction over a mean period of 7.7 ± 2.5 months. The IZC MS therapy provided 4 mm of distalization; there was 1.2 mm of intrusion of the first molar with 11.2° distal tipping. The maxillary incisors were retracted 4.7 mm and tipped lingually 13.4°. Overjet and overbite showed a reduction of 3.6 mm and 2.4 mm, respectively. The occlusal plane rotated clockwise 2.8°. The upper lip was retracted by 1 mm and the nasolabial angle increased 5.1°. There was an increase in the interpremolar and intermolar distances.ConclusionsTotal arch distalization of the maxillary dentition using IZC MS was effective in the treatment of Class II malocclusions.     

微钛钉种植体支抗单侧推磨牙向后的临床应用

目的:探讨运用微钛钉种植体支抗单侧推磨牙向后的临床及应用要点.方法:选择安氏Ⅱ类亚类错(牙合)7例,男2例,女5例,年龄15～30岁,平均18.7岁.轻中度拥挤,拥挤度平均在4～5mm,或伴上中线偏移,侧貌面下1/3无明显前突者.采用单侧颊侧植入微钛钉种植体,推磨牙向后,推力250g.疗程3～5个月,平均4个月.通过临床评价和矫治前后的照片、模型和头颅侧位片分析其治疗的有效性.结果:7例患者有效地应用微钛钉种植体支抗单侧推磨牙向后,非拔牙矫治纠正了单侧磨牙Ⅱ类远中关系、轻中度拥挤或中线偏移,取得较好的临床疗效.远移侧上颌第一磨牙远中平均移动4.2mm,平均移动速度(1.25±0.25)mm/月,有一定程度的颊向移动,水平旋转和垂直压低.上中切牙长轴倾斜度、下颌平面及面下1/3高度不变.结论:微钛钉种植体支抗单侧推磨牙向后,发挥了绝对强支抗作用,有效地远中移动上颌磨牙.矫治过程中,需注意诊断、设计、生物力学的考虑以及临床应用要点.     

控根辅弓在推磨牙远移中的应用

目的探讨控根辅弓联合Ⅱ类牵引,应用于口内弓上施以镍钛簧推磨牙远移的临床效果。方法21例安氏Ⅱ类错牙合病例采用口内弓设置NiTi簧,辅以反向控根辅弓及Ⅱ类牵引推磨牙往远中,治疗前后均摄X线头颅侧位片及治疗前后口内外X线片。结果1.0~4.2个月(平均2.6个月)磨牙关系达到中性或偏近中,上切牙无明显唇倾、磨牙略有伸长。结论控根辅弓配合Ⅱ类牵引的口内弓推磨牙往远中,方法简便易行,并能较好地控制好前牙唇倾。     

Effects of skeletally anchored Class II elastics: A pilot study and new approach for treating Class II malocclusion

Objective:To evaluate the skeletal, dentoalveolar, and soft tissue effects of skeletally anchored Class II elastics and compare them with a matched control group treated by a monobloc appliance for the correction of skeletal Class II malocclusion due to mandibular retrusion.Materials and Methods:Twelve patients (6 girls, 6 boys) were randomly divided into two groups. In the elastics group, six patients (12.9 ± 1.5 years of age; 3 boys, 3 girls) were treated with skeletally anchored Class II elastics. Two miniplates were placed bilaterally at the ramus of the mandible and the other two miniplates were placed at the aperture piriformis area of the maxilla. In the monobloc group (3 boys and 3 girls; mean age, 12.3 ± 1.6 years), patients used the monobloc appliance. The changes observed in each phase of treatment were evaluated using the Wilcoxon matched-pair sign test. Intergroup comparisons at the initial phase of treatment were analyzed by the Mann-Whitney U test.Results:There were statistically significant group differences in Co-Gn, B-VRL, U1-PP, U1-VRL, Ls-VRL, with significant increases in these parameters in the elastics group (P < .05). The mandibular incisors were protruded in the monobloc group (5.45 ± 1.23°), whereas they were retruded in the elastics group (−3.01 ± 1.66°; P < .01).Conclusions:The undesirable dentoalveolar effects of the monobloc appliance were eliminated by using miniplate anchorage. Favorable skeletal outcomes can be achieved by skeletal anchorage therapies which could be an alternative to treat skeletal Class II patients with mandibular deficiency.     

Treatment effects of skeletally anchored Forsus FRD EZ and Herbst appliances: A retrospective clinical study

Objective:To evaluate the skeletal, dentoalveolar, and soft tissue effects of the Forsus FRD appliance with miniplate anchorage inserted in the mandibular symphyses and to compare the findings with a well-matched control group treated with a Herbst appliance for the correction of a skeletal Class II malocclusion due to mandibular retrusion.Materials and Methods:The sample consisted of 32 Class II subjects divided into two groups. Group I consisted of 16 patients (10 females and 6 males; mean age, 13.20 ± 1.33 years) treated using the Forsus FRD EZ appliance with miniplate anchorage inserted in the mandibular symphyses. Group II consisted of 16 patients (9 females and 7 males; mean age, 13.56 ± 1.27 years) treated using the Herbst appliance. Seventeen linear and 10 angular measurements were performed to evaluate and compare the skeletal, dentoalveolar, and soft tissue effects of the appliances using paired and Student''s t-tests.Results:Both appliances were effective in correcting skeletal class II malocclusion and showed similar skeletal and soft tissue changes. The maxillary incisor was statistically significantly more retruded in the skeletally anchored Forsus FRD group (P < .01). The mandibular incisor was retruded in the skeletally anchored Forsus FRD group (−4.09° ± 5.12°), while it was protruded in the Herbst group (7.50° ± 3.98°) (P < .001).Conclusion:Although both appliances were successful in correcting the skeletal Class II malocclusion, the skeletally anchored Forsus FRD EZ appliance did so without protruding the mandibular incisors.     

Orthodontic treatment of a class II, 1 malocclusion including extractions of the 4 first molars

Orthodontic treatment of a Class II, 1 malocclusion in a 13-year-old boy is demonstrated. The first molars were extracted and an Edgewise-appliance was used.This casuistry was one of 8 cases accepted for The European Board of Orthodontics, July 1997.     

Influence of unilateral maxillary first molar extraction treatment on second and third molar inclination in Class II subdivision patients

Objective:To assess the maxillary second molar (M2) and third molar (M3) inclination following orthodontic treatment of Class II subdivision malocclusion with unilateral maxillary first molar (M1) extraction.Materials and Methods:Panoramic radiographs of 21 Class II subdivision adolescents (eight boys, 13 girls; mean age, 12.8 years; standard deviation, 1.7 years) before treatment, after treatment with extraction of one maxillary first molar and Begg appliances and after at least 1.8 years in retention were retrospectively collected from a private practice. M2 and M3 inclination angles (M2/ITP, M2/IOP, M3/ITP, M3/IOP), constructed by intertuberosity (ITP) and interorbital planes (IOP), were calculated for the extracted and nonextracted segments. Random effects regression analysis was performed to evaluate the effect on the molar angulation of extraction, time, and gender after adjusting for baseline measurements.Results:Time and extraction status were significant predictors for M2 angulation. M2/ITP and M2/IOP decreased by 4.04 (95% confidence interval [CI]: −6.93, 1.16; P  =  .001) and 3.67 (95% CI: −6.76, −0.58; P  =  .020) in the extraction group compared to the nonextraction group after adjusting for time and gender. The adjusted analysis showed that extraction was the only predictor for M3 angulation that reached statistical significance. M3 mesial inclination increased by 7.38° (95% CI: −11.2, −3.54; P < .001) and 7.33° (95% CI: −11.48, −3.19; P  =  .001).Conclusions:M2 and M3 uprighting significantly improved in the extraction side after orthodontic treatment with unilateral maxillary M1 extraction. There was a significant increase in mesial tipping of maxillary second molar crowns over time.     

The Hybrid Hyrax Distalizer,a new all-in-one appliance for rapid palatal expansion,early class III treatment and upper molar distalization

Abstract

Growing class III patients with maxillary deficiency may be treated with a maxillary protraction facemask. Because the force generated by this appliance is applied to the teeth, the inevitable mesial migration of the dentition can result in anterior crowding, incisor proclination and a possible need for subsequent extraction therapy. The Hybrid Hyrax appliance, anchored on mini-implants in the anterior palate, can be used to overcome these side-effects during the facemask therapy. In some class III cases, there is also a need for subsequent distalization after the orthopaedic treatment. In this paper, clinical application of the Hybrid Hyrax Distalizer is described, facilitating both orthopaedic advancement of the maxilla and simultaneous orthodontic distalization of the maxillary molars.     

成人上颌第一磨牙根长、根管数目及形状研究

目的：通过对离体上颌第一磨牙测量根长，观察牙根不同部位根管数目和形状，为临床治疗提供参考资料。方法：收集20岁以上人上颌第一恒磨牙，测量根长度后将牙根横切分为3部分：根上1／3、根中1／3和根尖1／3，在体视镜下观察不同部位的根管数目、形状。结果：上颌第一磨牙腭根、近颊根和远颊根长度分别是（13、82±1．51）mm、（13、06±1、12）mm和（11．64±0．85）mm。近颊根管上1／3双根管检出率为51．00％，根中1／3和根尖1／3分别为53．88％、54、09％；远颊根中1／3和根尖1／3偶见双根管。腭侧根管横截面以圆形为主，未见有双根或多根管存在；近颊根和远颊根管形状变异大，形状多样。结论：上颌第一磨牙腭根和远颊根长度相近，腭根比近颊根长约2—3mm；近颊根和远颊根管形状变异大，近颊根双根管约50％以上，偶见多根管。根管上1／3线条形时，根中1／3和根尖1／3多为双根管。     

Roots of the maxillary first and second molars in horizontal relation to alveolar cortical plates and maxillary sinus: computed tomography assessment for infection spread

The purposes of this study were to investigate the horizontal relationship of the roots of maxillary molars with the cortical plates and the maxillary sinus and to investigate the influence of these relationships on the spread of odontogenic infection. Computed tomography images of 120 control subjects and 49 patients with infection originating in the maxillary first or second molar were investigated. In the control group, more than 60% of the first molar roots contacted both palatal and buccal cortical plates (type A), while such contact was not seen in more than 60% of second molars. The floor of maxillary sinus was most frequently observed at the level between the bifurcation and apices of roots in both first and second molars. In patients with infection, cortical changes were more frequently seen on the buccal side than on the palatal side, and 80% of patients with buccal cortical change showed the position in which the buccal roots were close to the buccal cortical plate. Mucosal thickening of the maxillary sinus was found in 87.8%. The buccopalatal spread of odontogenic infection originating in the maxillary first and second molars was influenced by the horizontal root position in relation to the cortices.