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.     

Maxillary molar distalization with miniscrew-supported appliances in Class II malocclusion: A systematic review

Objectives:To evaluate the quantitative effects of miniscrew supported appliances for maxillary molar distalization in Class II malocclusion.Materials and Methods:The systematic search included MEDLINE, EMBASE, CINAHL, PsychINFO, Scopus, and key journals and review articles. The date of the last search was January 30, 2017. Methodological quality of the retrospective studies was graded by means of the Quality Assessment Tool for Quantitative Studies, developed for the Effective Public Health Practice Project (EPHPP) and prospective studies by means of Newcastle–Ottawa Scale.Results:In total, 298 studies were identified for screening, and 14 studies were eligible. The Quality Assessment Tool for Quantitative Studies rated all of the four included retrospective studies as moderate. The Newcastle–Ottawa Scale rated seven studies as high quality and three studies as low quality. The mean molar distalization values varied from 1.8 mm to 6.4 mm. Mean distal tipping of molars varied from 1.65° to 11.3°. The mean distal movement of premolars and incisors varied from 1.75 mm to 5.4 mm and 0.1 mm to 2.7 mm, respectively.Conclusions:Miniscrew-supported appliances are effective in molar distalization with distal movement of premolars with minimal anchorage loss and distal tipping of the molar teeth.     

Evaluation of the effects of the hybrid Pendulum in comparison with the conventional Pendulum appliance

Objective:To evaluate the anchorage control and distalization of maxillary molars with the hybrid Pendulum appliance and to compare the results with a conventional Pendulum appliance.Materials and Methods:This study was carried out on the pre-(T0) and post-(T1) treatment lateral cephalograms and dental casts of 43 patients with Angle Class II molar relationships who were treated with conventional or hybrid Pendulum appliances. The hybrid Pendulum (HP) group consisted of 22 patients (14 females; eight males; mean age 14.3 ± 2.43 years) and treatment results were compared with a conventional Pendulum appliance (CP) group, which consisted of 21 patients (15 females; six males; mean age 14.6 ± 3.39 years). Intragroup comparisons were made with Wilcoxon test and intergroup comparisons were made with Mann-Whitney U-test (P < .05).Results:The mean distalization duration was 0.70 ± 0.25 years in the HP group and 0.83 ± 0.4 years in the CP group. Maxillary first molars showed significant distal movement and tipping of 4.25 mm and 9.09° in the HP group, and 3.21 mm and 9.86° in the CP group. Loss of anchorage at the first premolars was significantly smaller in the HP appliance group compared to CP group. The second premolars distalized spontaneously in the HP group while they mesialized significantly in the CP group. Proclination and protrusion of maxillary incisors were greater with the CP appliance compared to the HP appliance.Conclusions:Maxillary molar distalization was achieved with both appliances. Mesialization of the anchorage unit was controlled successfully with the hybrid Pendulum; however, the conventional Pendulum appliance caused anchorage loss.     

“摆”式矫治器远中移动上颌磨牙的疗效分析

目的研究"摆"式矫治器远中移动磨牙的效果以及其对面部骨骼和上颌牙齿的影响。方法选择处于替牙期或恒牙早期,上颌牙列轻中度拥挤,磨牙远中关系的病例25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上颌第一、二磨牙均发生了远中倾斜移动;②上颌第一前磨牙发生了近中倾斜移动,上中切牙发生了唇向倾斜移动;③在垂直向上,第一磨牙位置无明显变化,上颌第二磨牙伸长。④前牙覆盖增加,覆减小;⑤MP-SN和前下面高(ANS-Me)增加。结论①"摆"式矫治器可以有效的远中移动上颌磨牙;②"摆"式矫治器主要影响上颌牙齿,而对面部骨骼影响较小;③"摆"式矫治器在远中移动磨牙的同时伴随有上颌磨牙远中倾斜和上颌前部支抗丧失。     

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.     

Long-term skeletal effects of high-pull headgear followed by fixed appliances for the treatment of Class II malocclusions

Objectives:The long-term skeletal effects of Class II treatment in growing individuals using high-pull facebow headgear and fixed edgewise appliances have not been reported. The purpose of this study was to evaluate the long-term skeletal effects of treatment using high-pull headgear followed by fixed orthodontic appliances compared to an untreated control group.Materials and Methods:Changes in anteroposterior and vertical cephalometric measurements of 42 Class II subjects (n = 21, mean age = 10.7 years) before treatment, after headgear correction to Class I molar relationship, after treatment with fixed appliances, and after long-term retention (mean 4.1 years), were compared to similar changes in a matched control group (n = 21, mean age = 10.9 years) by multivariable linear regression models.Results:Compared to control, the study group displayed significant long-term horizontal restriction of A-point (SNA = −1.925°, P < .0001; FH-NA = −3.042°, P < .0001; linear measurement A-point to Vertical Reference = −3.859 mm, P < .0001) and reduction of the ANB angle (−1.767°, P < .0001), with no effect on mandibular horizontal growth or maxillary and mandibular vertical skeletal changes. A-point horizontal restriction and forward mandibular horizontal growth accompanied the study group correction to Class I molar, and these changes were stable long term.Conclusions:One phase treatment for Class II malocclusion with high-pull headgear followed by fixed orthodontic appliances resulted in correction to Class I molar through restriction of horizontal maxillary growth with continued horizontal mandibular growth and vertical skeletal changes unaffected. The anteroposterior molar correction and skeletal effects of this treatment were stable long term.     

Molar Distalization with Different Pendulum Appliances: In Vitro Registration of Orthodontic Forces and Moments in the Initial Phase

Abstract. Aim: Registration of the orthodontic forces and moments acting with different types of pendulum appliance for non-compliance upper molar distalization in an in vitro study. Material and Methods: The purpose-designed test set-up comprised the following components: artificial maxilla with anchorage unit and two electrothermodynamic (ETD) molars, electronic measuring unit for temperature control and regulation, and a sensor unit with force-moment sensor, analog/digital converter and data readout unit. This set-up permitted virtually authentic simulation of in vivo conditions on the one hand and precise determination of the force systems on the other.The appliances investigated were the standard pendulum appliance with U-loop activation according to Hilgers and with uprighting activation according to Byloff, the M-pendulum with U-loop activation according to Scuzzo, and the Pendulum K with initial uprighting activation, toe-in bend and incorporated distal screw according to Kinzinger. Results and Conclusions: The effects shown by the standard pendulum appliance and the M-pendulum over a 3 mm simulated distalization increment were a marked decrease in the distally directed forces, and an increase in the intrusive and palatally directed forces as well as in the distoinclinatory, mesially inward, and palatally rotating moments.Activations in the U-loop region of the pendulum springs induced an increase in distally and buccally directed forces and in uprighting and buccally rotating moments as well as a marked rise in extrusive forces. Whereas the activation described by Hilgers led to mesially outward rotating moments, activation according to Scuzzo resulted in a further increase in the mesially inward rotating moments.In the measured standard pendulum appliances, uprighting activation at the end of the pendulum according to Byloff led to an increase in distally and buccally directed as well as in mildly intrusive forces, and to an increase in uprighting as well as in buccally and mesially outward rotating moments.With the Pendulum K according to Kinzinger, the initial toe-in bend and uprighting activation in the region of the end of the pendulum spring together with regular adjustment of the incorporated distal screw permitted virtually translatory molar distalization: constantly distalizing forces with slight intrusive, buccally directed, and rotating side effects.     

摆形矫治器用于安氏Ⅱ类Ⅰ分类错(牙合)畸形对上颌牙列和骨骼的影响

目的 采用摆形矫治器对上颌磨牙远中移动的同时,观察对上颌前牙及双尖牙的副影响。方法 在临床上收集12名患者,男4名,女8名,平均年龄11.1岁,患者均为安氏Ⅱ类Ⅰ分类错(牙合)畸形,非拔牙矫治,均使用摆形矫治器远中移动磨牙来纠正Ⅱ类磨牙关系为Ⅰ类磨牙关系,牙弓内获得足够的间隙。比较治疗前后的头影测量片。结果 上颌磨牙远中倾斜8.34°(SD=8.37°),远中移动3.37mm(SD=2.10mm);上颌切牙移动2.4mm(SD=4.57);(牙合)平面向前上倾斜1.09°(SD=1.76°);下面高(ANS-Me)增加2.79mm(SD=2.03mm)。结论对摆形矫治器远中移动磨牙的疗效是肯定的,但是在治疗过程中,支抗的丧失,上颌切牙的唇倾、前牙覆(牙合)覆盖增加以及下面高的增加是治疗的副影响,而且磨牙远中移动的过程中,伴有牙冠较大量的远中倾斜。因此,提醒临床医生在使用类似的矫治器时应慎重。     

Skeletal versus conventional intraoral anchorage for the treatment of class II malocclusion: dentoalveolar and skeletal effects

Background

The purpose of this retrospective study is to investigate the dentoalveolar and skeletal effects of two distalizing protocols featuring different anchorage systems used in patients with class II malocclusion: the MGBM system (skeletal anchorage) and Pendulum (intraoral anchorage).

Methods

The sample comprised 57 patients who were assigned to one of the two treatments: the MGBM group (30 patients, mean age 13.3 ± 2.3 years) or the Pendulum group (27 patients, mean age 12.8 ± 1.7 years). Three serial cephalograms were obtained at baseline (T0), after molar distalization (T1), and after fixed appliance treatment (T2). Esthetic, skeletal, and dental parameters were considered. Pancherz''s superimposition method was used to assess sagittal dental changes. The initial and final measurements and treatment changes were compared by means of a paired t test or a paired Wilcoxon test. Statistical significance was tested at p < 0.05, p < 0.01, and p < 0.001.

Results

In the MGBM group, the upper molar distalization was achieved in 7 months and showed a mean value of 4.9 mm (ms-PLO); the amount of molar relationship correction was 5.9 mm. In the Pendulum group, the upper molar distalization was obtained in 9 months and showed a mean value of 2.5 mm (ms-PLO), while the molar relationship correction amounted to 4.9 mm. Anterior anchorage loss occurred in both groups, although in the MGBM group, there was less mesial movement of the premolars.

Conclusions

The MGBM system and the Pendulum appliance are both effective in the correction of class II malocclusions. The MGBM system was found to be more efficient than the Pendulum appliance, producing greater molar distalization in a shorter treatment time.     

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.     

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提要：推磨牙远中移动是消除牙列轻、中度拥挤,开拓间隙,改善安氏Ⅱ类错牙合磨牙关系的方法之一。本文就推磨牙远中移动技术的研究进展做一综述,并探讨磨牙远移矫治器的适用范围。     

A preliminary report of a new design of cast metal fixed twin-block appliance

Abstract

The present paper describes a cast metal fixed twin-block appliance utilized to correct a Class II malocclusion, which is designed for full-time wear. The object of the present paper is to achieve rapid functional correction of Class II malocclusions by transmitting favourable occlusal forces to inclined planes which are cemented to the posterior teeth. In the meantime, pre-adjusted fixed edgewise appliances can be placed on the anterior teeth to correct their malpositions. This new functional appliance design may shorten the total treatment duration and reduce the need for patient compliance.     

摆式矫治器结合直丝弓矫治器治疗Ⅱ类错的疗效分析

目的 分析安氏Ⅱ类错患者经摆式矫治器结合直丝弓矫治器治疗后的牙颌面结构变化,探讨此方法建立正常咬合关系的机制。方法 选择牙源性安氏Ⅱ类错患者24例,在治疗前(T1期)、推磨牙向远中后(T2期)、直丝弓矫治结束后(T3期),拍摄头颅定位侧位片。采用SPSS12.0软件包进行配对t检验。结果 ①T1期-T2期,上颌第一二磨牙均远中移动,但伴随着上颌切牙唇倾、第一前磨牙近中移动并倾斜、第一磨牙远中倾斜及下颌平面顺时针旋转等副作用。②T1期-T3期,下颌综合长度、前下面高和升支高度增加显著(P<0.01)。上颌第一前磨牙、第一磨牙的矢状向位置无显著性差异,切牙唇倾2.9°(P<0.05)。即使增强了支抗控制,固定矫治阶段上颌第一磨牙近中移动3.0mm(P<0.01)。结论 摆式矫治器可以有效的远中移动上颌磨牙,但是Ⅰ类磨牙关系的建立是颌骨差异性生长和牙齿移动的综合结果。     

摆形矫治器矫治不同垂直骨面型安氏Ⅱ类错的疗效评价

目的　探讨摆形矫治器矫治不同垂直骨面型安氏Ⅱ类错的疗效及对牙颌面的影响。方法　对30例样 本(低角组、均角组、高角组各10例)治疗前后的24项X线头影测量指标进行测量和比较分析。结果　上颌磨牙在 不同的垂直骨面型中远中移动的距离不同,低角组移动最小,高角组移动最大;上颌磨牙在3组中均被压低,但差 别无统计学意义;各组样本第一双尖牙向近中移动量和前牙覆盖增加量不同,低角组最多,高角组最少。结论　摆 形矫治器可有效远中移动磨牙,在不同的垂直骨面型磨牙均被压低,为摆形矫治器用于矫治AngleⅡ类高角患者提 供了理论依据。     

Comparative evaluation of treatment effects between two fixed functional appliances for correction of Class II malocclusion: A single-center,randomized controlled trial

Objective:The objective of this study was to evaluate and compare the effects of PowerScope and Forsus in the treatment of Class II division 1 malocclusion.Materials and Methods:This was a 2-arm parallel, double-blind, randomized, controlled trial. A total of 28 Class II division 1 malocclusion patients indicated for treatment with fixed functional appliances were randomized and equally divided (n = 14) among PowerScope (American Orthodontics, Sheboygan, Wis; mean age 14.11 ± 1.3 years) and Forsus (3M Unitek Corp, Monrovia, Calif; mean age 15.5 ± 1.1 years) groups. Skeletal and dentoalveolar effects of PowerScope and Forsus were compared. The secondary outcomes were evaluation of patient comfort and operator convenience. Randomization was accomplished with a 1:1 allocation ratio, and concealment was achieved by sealed opaque envelopes. The participants and data collectors were all blinded to study group allocation. Data were analyzed for 26 patients, 13 in each group, as one patient from each group discontinued treatment. Statistical comparisons were carried out using Student''s t-tests and chi square tests (P ≤ .05).Results:A significantly greater mesial mandibular movement and improvement in sagittal skeletal relation were found in the Forsus patients (P ≤ .05). The forward movement of the mandibular molar and incisors were greater in the PowerScope patients (2.3 mm and 2.80 mm) than in the Forsus patients (1.9 mm and 2.38 mm).Conclusions:Both PowerScope and Forsus are effective in correcting Class II malocclusion. The percentage of dentoalveolar effects in correcting Class II malocclusion is more for PowerScope when compared with Forsus. Patient comfort was the same with both appliances. This trial was registered.     

无托槽隐形矫治器远移上颌磨牙的疗效评价

目的:评价无托槽隐形矫治器远中移动上颌磨牙的疗效.方法:选取安氏Ⅱ类错(牙合)患者15例,平均年龄为25.3岁.应用无托槽隐形矫治器远中移动上颌磨牙,通过重叠磨牙远移前后的三维数字化模型,并进行三维测量分析评价其远中移动磨牙的疗效.结果:双侧第一磨牙均平均向远中移动2.58 mm,左右侧第二磨牙分别平均向远中移动2.57 mm和2.68 mm,双侧中切牙均平均向近中移动0.34 mm.双侧中切牙在水平向上无明显移动,左右侧第一磨牙均平均颊向移动0.96 mm和0.97mm,左右侧第二磨牙平均颊向移动1.01 mm和1.11 mm.双侧中切牙无明显伸长或压低,双侧第一磨牙均平均压低0.26 mm,左右侧第二磨牙分别平均压低0.37 mm和0.36 mm.双侧第一磨牙和第二磨牙均无明显颊腭向旋转.结论:无托槽隐形矫治器能有效地远中移动上颌磨牙,但会引起轻微的磨牙压低和前牙支抗丧失.     

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。