Bone-anchored maxillary protraction to correct a class III skeletal relationship: A multicenter retrospective analysis of 218 patients

This study evaluated the impact of class III correction by elastic traction on four miniplates and the failure rate of bone-anchored miniplates in nonsyndromic patients. A total of 218 patients (112 males and 106 females; average 11.4 years), treated by 38 orthodontists, received four miniplates (total 872 miniplates) from 2008 to 2016 at three maxillofacial centers in two countries. Factors affecting the success and failure of the miniplates were retrospectively examined and skeletal changes on cephalometric radiographs examined for 52 patients. Elastic traction was performed for 22.9 months, on average. The miniplate survival rate was 93.6%; 25.7% of the patients suffered failure of one of the miniplates. Postoperative antibiotics and placement of the neck of the miniplate in the attached gingiva significantly improved the success rate. Miniplate failure was six times higher in the maxilla and occurred more in younger patients. Self-drilling screws were significantly better than self-tapping screws for fixing the miniplate. Small cephalometric changes were seen: SNA (+1.9°), SNB (+0.4°), ANB (+1.4°), Wits analysis (+1.3 mm). In conclusion, bone-anchored maxillary protraction on four miniplates is an effective method for correcting a class III relationship, but has less skeletal effect than previously reported in the literature.     

Maxillary protraction using a hybrid hyrax-facemask combination

Background

The aim of this in study was the evaluation of treatment outcomes after using a hybrid hyrax-facemask combination in growing class III patients.

Methods

Treatment of 16 children (mean age 9.5 ± 1.3 years) was investigated clinically and by means of pre- and post-treatment cephalograms. Changes in sagittal and vertical, and dental and skeletal values were evaluated and tested for statistically significant differences.

Results

All mini-implants remained stable during treatment. Mean treatment duration was 5.8 ± 1.7 months. There was a significant improvement in skeletal sagittal values: SNA, +2.0°; SNB, -1.2°; ANB, +3.2°; WITS appraisal, +4.1 mm and overjet, +2.7 mm. No significant changes were found concerning vertical skeletal relationships and upper incisor inclination. In relation to A point, the upper first molars moved mesially about 0.4 mm (P = 0.134).

Conclusions

The hybrid hyrax-facemask combination seems to be effective for orthopaedic treatment in growing class III patients. Unwanted maxillary dental movements can be avoided due to stable skeletal anchorage.     

Comparison of facemask therapy effects using skeletal and tooth-borne anchorage:: A longitudinal retrospective study

ObjectivesTo investigate long-term outcomes of dentoskeletal changes induced by facemask therapy using skeletal anchorage in Class III patients and compare them to those of conventional tooth-borne anchorage.Materials and MethodsThis retrospective study included 20 patients who received facemask (FM) therapy with miniplates as anchorage for maxillary protraction (Miniplate/FM group, 10.6 ± 1.1 years old [mean ± SD]) and 23 patients who were treated with facemask with rapid maxillary expander (RME/FM group, 10.0 ± 1.5 years old [mean ± SD]). Dentoskeletal changes were evaluated using lateral cephalograms at pretreatment (T1), after facemask therapy (T2), and at the post-pubertal stage (T3). Cephalometric changes were compared between groups and clinical success rates at T3 were evaluated.ResultsSNA and A to N perpendicular to FH increased significantly more in the Miniplate/FM group than in the RME/FM group when comparing short-term effects of facemask therapy (T1–T2). ANB, Wits appraisal, Angle of convexity, mandibular plane angle, and overjet decreased significantly more in the RME/FM group than in the Miniplate/FM group after facemask therapy (T2–T3). A more favorable intermaxillary relationship was observed in the Miniplate/FM group than in the RME/FM group in long-term observations (T1–T3). Clinical success rate at T3 was 95% in the Miniplate/FM group and 85% in the RME/FM group.ConclusionsFacemask therapy with skeletal anchorage showed a greater advancement of the maxilla and more favorable stability for correction of Class III malocclusion in the long-term than conventional facemask therapy with tooth-borne anchorage.     

Dentofacial effects of two facemask therapies for maxillary protraction: Miniscrew implants versus rapid maxillary expanders

Objective:To compare the dentofacial effects of maxillary protraction with two facemask therapies in growing Class III patients: facemask in association with miniscrew implants (MSI/FM) and facemask with rapid maxillary expanders (RME/FM).Materials and Methods:Forty-three Chinese patients with Class III malocclusion and maxillary deficiency were randomly assigned to a MSI/FM sample of 20 patients and a RME/FM sample of 23 subjects. The changes in dentofacial cephalometric variables from the beginning (T1) to the end of treatment (T2) were compared with t-test for paired samples in both groups and for independent samples between the two groups.Results:No significant cephalometric differences were observed between the two groups in active treatment effects except for maxillary dental variables. However, significant favorable changes in both maxillary and mandibular skeletal components were noted in two groups after treatment. Sagittal measurements showed the maxilla was advanced, mandibular projection was reduced, and the relative sagittal intermaxillary discrepancy improved. Patients experienced additional unfavorable outcomes of clockwise rotation of the mandible as well as retroclination of the lower incisors. The soft tissue profile was improved remarkably in both groups. Proclination of the maxillary incisors and mesialization of the maxillary dentition were significantly different between the two groups. The increases in U1-SN, U1-VR, and U6-VR were 6.41°, 2.78 mm, and 1.24 mm less in the MSI/FM group than in the RME/FM group, respectively.Conclusions:Compared with the RME/FM therapy, the MSI/FM protocol using a smaller magnitude of protraction force improves skeletal relationships and soft tissue profile and reduces the undesired dentoalveolar effects.     

A Bayesian network meta‐analysis of orthopaedic treatment in Class III malocclusion: Maxillary protraction with skeletal anchorage or a rapid maxillary expander

To evaluate and compare the effectiveness of orthopaedic treatment for Class III malocclusions using skeletal anchorage or a rapid maxillary expander for maxillary protraction. Electronic databases, including PubMed, EMBASE, Cochrane Library and Web of Science, were searched for randomized controlled trials (RCTs) and non‐randomized clinical trials (CCTs) for orthopaedic treatment of Class III malocclusions. Five interventions were studied: a facemask with a maxillary temporary anchorage device (MTAD), a bone‐anchored rapid maxillary expansion (BARME), a rapid maxillary expansion (RME), an alternate rapid maxillary expansion and contraction (Alt‐RAMEC), and a bone‐anchored intermaxillary traction (BAIMT). Eight outcomes (SNA, SNB, ANB, overjet, SN‐GoGn, ANS‐Me, IMPA (L1‐MP), and U1‐PP) were statistically polled. We conducted network meta‐analysis using R statistical software with the GeMTC package. Twenty‐five studies met the inclusion criteria. Compared with the RME group, the Alt‐RAMEC group (mean difference (MD): 1.3; 95% credibility interval (CrI): 0.26, 2.3) and MTAD group (MD: 0.85; 95% CrI: 0.065, 1.6) showed a better effect on ANB in CCTs. Regarding the vertical relationship, the BAIMT group (MD: ?2.2; 95% CrI: ?5.2, 0.73) showed a smaller effect regarding increasing the vertical dimension of ANS‐Me. The RME, MTAD and Alt‐RAMEC group showed a higher ability to decrease the angle of L1‐MP. The Alt‐RAMEC and MTAD protocol have a higher possibility to obtain a skeletal and tooth effect in sagittal relationships. The BAIMT protocol can acquire a better skeletal effect in sagittal relationships with less vertical and dental changes. More well‐designed RCTs are needed to ensure that the conclusion is reliable.     

The short-term treatment effects of face mask therapy in Class III patients based on the anchorage device: Miniplates vs rapid maxillary expansion

Objective:To compare the short-term treatment effects of face mask therapy with miniplates (FM-MP) and face mask therapy with rapid maxillary expansion appliance (FM-RME) in growing Class III malocclusion patients with maxillary hypoplasia.Materials and Methods:Twenty patients were allocated into two groups according to the anchorage device: FM-MP group (n  =  10; mean age  =  11.2 ± 1.2 years; miniplates in the zygomatic buttress area) and FM-RME group (n  =  10; mean age  =  10.7 ± 1.3 years; bonded or banded RME). The face mask was applied for 12 to 14 hours/day in both groups with a force of 400 g/side directed 30° downward and forward from the occlusal plane. Lateral cephalograms were taken before (T1) and after FM-MP or FM-RME therapy (T2). Skeletodental and soft-tissue variables were measured. Paired and independent t-tests were performed for statistical analysis.Results:Both groups exhibited significant forward movement of point A and posterior repositioning and opening rotation of the mandible from T2 to T1. The FM-MP group showed significant protraction of orbitale (ΔSNO), and the FM-RME group showed a decrease in overbite and an increase in Björk sum. Comparing the amount of changes between the two groups, the FM-MP group displayed greater forward movement of the maxilla than the FM-RME group (ΔSNA, ΔA to N perp, all P < .05). However, the FM-RME group exhibited a greater opening rotation of the mandible (ΔSNB, Björk sum, all P < .01; ΔPog to N-perp, P < .05) and labioversion of the maxillary incisors (ΔU1-FH, P < .05).Conclusion:FM-MP therapy induces a greater advancement of the maxilla, less posterior repositioning and opening rotation of the mandible, and less proclination of the maxillary incisors than FM-RME therapy.     

骨性Ⅲ类畸形上颌前方牵引治疗的三维测量分析

目的： 通过锥形束CT（cone-beam computed tomography, CBCT）研究骨性Ⅲ类错颌畸形患者上颌前方牵引治疗前后的变化,从三维方向上探讨上颌前方牵引治疗的机制。方法：选取14例恒牙列早期骨性Ⅲ类错颌畸形患者,男6例,女8例,年龄10~12岁,平均10.9岁,采用上颌前方牵引治疗。牵引治疗前、后,进行CBCT三维扫描,采用Dolphin 11.0对骨组织及牙进行三维重建、建立三维坐标体系,选择23个标志点进行测量、分析。测量结果使用SPSS 17.0软件包进行统计学分析。结果：上颌前方牵引后,A-冠状面的距离、SNA、ANB均显著增大 (P<0.01);A-水平面的距离显著增大 (P<0.05),ANS-PNS增大,有显著差异 (P<0.05),上颌骨向前、向下生长。Po-S-N显著增大(P<0.01),SNB显著减小 (P<0.05),提示颏部向下、向后旋转,下颌生长得到抑制。U1j-冠状面的距离显著增大(P<0.01),提示上切牙前移;U1牙长轴-SN交角显著增大 (P<0.05),提示上切牙唇倾。U6j-水平面的距离、U6j-冠状面的距离均显著增大（P<0.05）,提示上颌磨牙近中移动、伸长。额颌缝等4条骨缝三维方向上均有变化,但无显著差异（P>0.05）。结论：上颌前方牵引后,经CBCT三维测量,证实翼腭缝等骨缝的生长改建在上颌骨生长过程中发挥了重要作用,上颌骨及上颌牙明显向前、向下生长;下颌骨生长得到抑制。     

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.     

Long-term stability of maxillary protraction therapy in Class III patients with complete unilateral cleft lip and palate

Objectives:This study evaluated the long-term stability of maxillary protraction (MP) in patients with complete unilateral cleft lip and palate (UCLP) and identified factors influencing relapse and long-term outcomes.Materials and Methods:Twenty-three adolescents with UCLP who underwent MP therapy were recalled when craniofacial growth was close to completion. Subjects exhibiting reverse/positive overjets were assigned to unstable/stable groups. Lateral cephalometric measurements were made before treatment (T0), after active treatment (T1), and at the end of the growth spurt (T2).Results:About 63% of the subjects exhibited positive overjets during follow-up. The unstable group demonstrated higher B–x and Co–Gn distances than the stable group (both P < .05) at T0. More short-term (T0–T1) sagittal advancement of point A (A–y) was evident in the unstable group than in the stable group (P < .05), but no long-term difference was apparent between the two groups (P = .481). During the posttreatment period (T1–T2), the SNA angle and maxillary incisor protrusion (U1–SN angle) were considerably lower in the unstable group than in the stable group (both P < .05). Overall, the unstable group exhibited a lower increase in the vertical extent of point A (A–x) than the stable group from T0 to T2 (P < .05).Conclusions:In the long term, MP affords favorable maxillary advancement in patients with UCLP. A mandibular excess at T0 and vertical maxillary hypoplasia may contribute to the long-term relapse of a reverse overjet.     

Evaluation of the effects of skeletal anchoraged Forsus FRD using miniplates inserted on mandibular symphysis: A new approach for the treatment of Class II malocclusion

Objective:To evaluate the skeletal, dentoalveolar, and soft tissue effects of the Forsus Fatigue Resistant Device (FRD) appliance with miniplate anchorage for the treatment of skeletal Class II malocclusion.Material and Methods:The prospective clinical study group included 17 patients (11 girls and 6 boys; mean age 12.96 ± 1.23 years) with Class II malocclusion due to mandibular retrusion and treated with skeletal anchoraged Forsus FRD. After 0.019 × 0.025-inch stainless steel archwire was inserted and cinched back in the maxillary arch, two miniplates were placed bilaterally on the mandibular symphysis. Then, the Forsus FRD EZ2 appliance was adjusted to the miniplates without leveling the mandibular arch. The changes in the leveling and skeletal anchoraged Forsus FRD phases were evaluated by means of the Paired and Student''s t-tests using the cephalometric lateral films.Results:The success rate of the miniplates was found to be 91.5% (38 of 42 miniplates). The mandible significantly moved forward (P < .001) and caused a significant restraint in the sagittal position of the maxilla (P < .001). The overjet correction (−5.11 mm) was found to be mainly by skeletal changes (A-VRL, −1.16 mm and Pog-VRL, 2.62 mm; approximately 74%); the remaining changes were due to the dentoalveolar contributions. The maxillary and mandibular incisors were significantly retruded (P < .001).Conclusion:This new approach was an effective method for treating skeletal Class II malocclusion due to the mandibular retrusion via a combination of skeletal and dentoalveolar changes.     

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.     

利用颧牙槽嵴区种植钉矫正边缘性Ⅱ类错(牙合)

目的:通过利用颧牙槽嵴区种植钉支抗整体远移上牙列而矫治边缘性Ⅱ类错(牙合),探索此类错(牙合)更简单、有效的矫治方法.方法:选择9例前牙前凸青少年(13～17岁)正畸患者,前牙Ⅰ～Ⅱ度深覆盖,磨牙为尖对尖远中关系,开唇露齿.正畸拔除上颌7或8牙胚,在颧牙槽嵴区植入自攻式微种植钉支抗,采用直丝弓矫治器,整平后直接在O.019×0.025英寸不锈钢方丝上用微种植钉支抗远中移动整个上牙列,并作治疗前、后X线头影测量分析,采用SPSS 17.0软件包中的配对t检验比较治疗前、后上、下唇位置,上、下颌第一磨牙及切牙的移动.结果:治疗后凸面型得到明显改善,唇齿关系更和谐,上颌切牙及磨牙较治疗前向远中移动,牙轴处于正常倾斜范围,面中部未因拔牙而出现饱满度塌陷.前、后牙覆(牙合)、覆盖正常,后牙、尖牙均为Ⅰ类关系,平均疗程14个月.结论:种植支抗可以整体远移上牙列,矫治边缘性Ⅱ类错(牙合),且疗效更好,疗程更短.     

骨种植钉前牵引对骨性Ⅲ类错患者软硬组织侧貌的影响

目的研究采用骨种植钉前牵引对骨性Ⅲ类错患者软、硬组织侧貌的改变。方法选取18例需行前牵引矫治的生长发育期骨性Ⅲ类错患者,采用双侧上颌颧牙槽嵴植入骨种植钉配合面框式前牵引,平均治疗时间为9个月,力值为（3.5±0.1）N。治疗前后头影测量采用Legan&Burstone软组织分析法以及相关硬组织测量,分析比较患者治疗前后软、硬组织变化情况。结果所有患者Ⅲ类错均得到改善,鼻底趋于丰满,颏部顺时针旋转,侧貌由凹面型变为直面型,下唇突度减小,软组织上下面高比、鼻唇角、上唇突度及颏唇沟深度无明显变化。上前牙无明显变化,下前牙舌倾,上颌骨向前生长,A点前移,SNA、ANB增大;SNB减小,下颌骨顺时针旋转。结论骨种植钉前牵引可促进上颌生长,使面中份丰满,且对上颌前牙轴倾度无影响,从而纠正骨性Ⅲ类错。     

Two-phase treatment in a patient with a skeletal Class III malocclusion: Early orthopedic treatment and subsequent camouflage treatment with temporary anchorage devices

In this case report, we describe the outcome of a two-phase orthodontic approach used to treat a 4-year and 8-month-old girl who exhibited excessive negative overjet and skeletal Class III jaw relationship. In Phase I treatment, growth modification using a protraction headgear appliance was used to normalize maxillomandibular growth. A forward growth of the maxilla and a normal overjet were achieved. During pubertal growth period, a skeletal Class III jaw relationship persisted due to differential jaw growth. A Phase II camouflage treatment with the help of temporary anchorage devices (TADs) was used to distalize the mandibular dentition. Good occlusion and facial esthetics were achieved, and the outcome has been maintained for 2 years after completion of the active treatment.     

微型种植体与口外弓治疗成人骨性Ⅱ类错（牙合）的比较张雄单丽华赵士芳黄吉娜毛靖王虎中郭家平王蕾赵今史建陆微型种植体与口外弓治疗成人骨性Ⅱ类错（牙合）的比较

目的 比较微型种植体和口外弓作为强支抗在治疗成人骨性II类错（牙合）中的临床效果.方法 微型种植体支抗组16名,口外弓支抗组10名,收集两组治疗前后的X线头颅侧位定位片,通过X线头影测量比较两组的上下颌骨及上下颌牙齿的各角度、线距的变化.结果 两种方法在对上下颌骨的影响、覆（牙合）覆盖的控制上有相同的效果,但对上颌前后牙的移动上两种方法有明显区别（P〈0.05）,上颌磨牙近中移动量分别为1.1mm（微型种植体组）和2.6mm（口外弓组）,上颌切牙内收量8.9mm（微型种植体组）和5.5mm（口外弓组）.结论 两种加强支抗的方法在正畸治疗中均可获到较好的治疗效果,但微型种植体支抗在上颌磨牙的近中移动和上颌切牙的内收上更具有优势.     

Effect of Class III bone anchor treatment on airway

Objectives:To compare airway volumes and minimum cross-section area changes of Class III patients treated with bone-anchored maxillary protraction (BAMP) versus untreated Class III controls.Materials and Methods:Twenty-eight consecutive skeletal Class III patients between the ages of 10 and 14 years (mean age, 11.9 years) were treated using Class III intermaxillary elastics and bilateral miniplates (two in the infra-zygomatic crests of the maxilla and two in the anterior mandible). The subjects had cone beam computed tomographs (CBCTs) taken before initial loading (T1) and 1 year out (T2). Twenty-eight untreated Class III patients (mean age, 12.4 years) had CBCTs taken and cephalograms generated. The airway volumes and minimum cross-sectional area measurements were performed using Dolphin Imaging 11.7 3D software. The superior border of the airway was defined by a plane that passes through the posterior nasal spine and basion, while the inferior border included the base of the epiglottis to the lower border of C3.Results:From T1 to T2, airway volume from BAMP-treated subjects showed a statistically significant increase (1499.64 mm³). The area in the most constricted section of the airway (choke point) increased slightly (15.44 mm²). The airway volume of BAMP patients at T2 was 14136.61 mm³, compared with 14432.98 mm³ in untreated Class III subjects. Intraexaminer correlation coefficients values and 95% confidence interval values were all greater than .90, showing a high degree of reliability of the measurements.Conclusion:BAMP treatment did not hinder the development of the oropharynx.     

骨性III类错牙合畸形患者正颌手术前后咀嚼肌功能变化的初步研究

目的:应用肌电图仪评价骨性III类错牙合畸形患者正颌手术前后咀嚼肌功能的变化。方法:收集16例骨性III类错牙合畸形需正颌手术病例和20例正常牙合对照组,应用MedelecSynergy肌电图仪分别在静息放松、正中紧咬、前伸、开口、侧方和咀嚼运动时,测定双侧颞肌前束、咬肌和二腹肌前腹的表面募集电位,并计算其肌不对称指数运动。病例组在术后3个月和6个月时重复测定,采用t检验进行统计学分析,并与对照组进行比较。结果:手术前病例组咀嚼肌电位小于对照组,尤以紧咬和咀嚼时差异显著(P<0.05),肌不对称指数与对照组无差异。术后3个月时,部分肌功能恢复,但紧咬和咀嚼时募集电位下降显著(P<0.001),肌不对称指数也增大,提示此时肌功能尚未完全恢复。术后6个月各种功能运动时的募集电位均大于术前水平,肌不对称指数则基本小于术前水平,说明肌功能有所改善。结论:骨性III类错牙合畸形患者手术前咀嚼肌功能弱于对照组,正颌手术矫正了颌骨位置和咬合关系,改善了患者的咀嚼肌功能。