Stability of maxillary interincisor diastema closure after extraction orthodontic treatment

ObjectivesTo evaluate the stability of maxillary interincisor diastema closure and the relationship between space relapse and interincisor diastema width, overjet, overbite, angulations between adjacent maxillary anterior teeth and presence of intermaxillary osseous cleft after orthodontic treatment with extractions.Materials and MethodsTwenty-four individuals with a maxillary interincisor diastema pretreatment, treated with maxillary first premolar extractions were evaluated. Dental casts and panoramic radiographs taken at pretreatment (T1), posttreatment (T2), and posttreatment follow-up (T3) were assessed. Periapical radiographs at T1 and T2 were also evaluated. Diastema relapse was assumed when T3-T2 interincisor space change was greater than zero. Diastema relapse was considered clinically significant when it was at least 0.50 mm. Data were analyzed using repeated-measures analysis of variance followed by post hoc Tukey tests or Friedman followed by Wilcoxon tests. T-test or Mann-Whitney U-test, Pearson correlation coefficient, and multiple linear regression analyses were also performed.ResultsNo statistically significant relapse of maxillary interincisor diastemas was found. The percentage of clinically significant relapse of the maxillary interincisor diastemas was 27.78%. Specifically, for the interincisor midline diastema, it was 8.33%.ConclusionsMaxillary interincisor diastema closure showed no statistically significant relapse after orthodontic treatment with premolar extractions. Clinically significant stability for maxillary interincisor diastema closure was 72.22% and, specifically, for interincisor midline diastema closure, it was 91.67%.     

Influence of temperature and humidity on the long-term storage of latex and non-latex orthodontic elastics

Objectives: The objective of this study was to evaluate the influence of long-term storage on latex and non-latex orthodontic elastics.

Materials and methods: The sample consisted of 300 orthodontic elastics, 150 latex and 150 non-latex (American Orthodontics^® *(AO) and Morelli^®) of medium force and a standard size of 3/16′′ divided into 20 groups, 10 for each manufacturer, with 15 specimens each. The groups (G1*–G10* and G1–G10) were made up based on the manufacturer, storage temperature (ambient and refrigerated), material, and ambient humidity (exposed and non-exposed). The elastics were stretched and their forces measured in five progressive increases of 100% of their inner diameter, starting at a level of 200% stretching, by the MESDAN LAB 3000^® (MESDAN, Italy) testing machine. The tests were carried out at two different times: immediately in as-received state and again after 1 year. Data were analysed using SPSS 16.0 software, the Student’s t-test, one-way analysis of variance (ANOVA) and the Tukey’s post-test.

Results: There was a statistically significant difference between the average forces exerted by the latex elastics compared to the non-latex elastics for all distention levels evaluated, except for 300%; however, the different storage conditions of temperature and humidity did not interfere in the mechanical properties.

Conclusion: Both the latex and non-latex elastics may be stored under any of the conditions tested in the present study, since there were no changes in the potential of the force exerted by the elastics in relation to their percentage stretch over a 1-year period.     

Management of the Class III malocclusion treated with maxillary expansion,facemask therapy and corrective orthodontic. A 15-year follow-up

The facial growth of Class III malocclusion worsens with age, in this case, the early orthopedic treatment, providing facial balance, modifying the maxillofacial growth and development. A 7.6-year old boy presented with Class III malocclusion associated with anterior crossbite; the mandible was shifted to the right and the maxilla had a transversal deficiency. Rapid maxillary expansion followed by facemask therapy was performed, to correct the anteroposterior relationship and improve the facial profile. The patient was followed for a 15-year period, after completion of the treatment, and stability was observed. Growing patients should be monitored following their treatment, so as to prevent malocclusion relapse.     

Periodontal status of neighboring teeth after orthodontic closure of mandibular extraction sites

abstract — The gingival health, pocket depth and loss of fiber attachment of the mandibular first molars and first premolars were studied by clinical and radiographic methods after the embedded second premolar had been surgically removed on one side and extracted after eruption on the other, and the spaces had been closed orthodontically. Twenty-nine children participated in the study. Their mean age at the time of tooth removal was 11 years 3 months. The mean duration of the treatment was 20 months, and the children were examined 1 1/2 to 2 years after removal of the bands. The gingival status was generally similar on both sides. Some constriction of the alveolar process was observed in more than half the cases, both after extraction and after surgical removal. The loss of attachment on the buccal and lingual surfaces was approximately the same in both groups, whereas the radiographic distance from the cementoenamel junction to the bone margin on the proximal surfaces adjacent to the removed tooth was somewhat greater after extraction than after surgical removal.     

Maxillary protraction after surgically assisted maxillary expansion

This case report describes the orthodontic treatment of a 32-year-old woman with aClass III malocclusion, whose chief compliant was her dentofacial esthetics. Thepretreatment lateral cephalometric tracings showed the presence of a Class IIIdentoskeletal malocclusion with components of maxillary deficiency. After discussionwith the patient, the treatment option included surgically assisted rapid maxillaryexpansion (SARME) followed by orthopedic protraction (Sky Hook) and Class IIIelastics. Patient compliance was excellent and satisfactory dentofacial esthetics wasachieved after treatment completion.     

釉基质蛋白衍生物对大鼠牙移动后复发和牙根修复的影响

目的:观察釉基质蛋白衍生物对大鼠正畸牙移动后早期复发和牙根吸收的影响.方法:选用20只10周龄雄性SD大鼠,实验组和对照组各10只,在左上第一磨牙施加100 g力,使其近中移动,加力14d后拆除装置.自拆除加力装置起,实验组局部注射釉基质蛋白衍生物,对照组不注射任何药物.分别于拆除装置后当天及第14天分别行Micro-CT活体扫描,分析牙根吸收陷窝以及牙移动距离的变化.采用SPSS19.0软件包对数据进行统计学分析.结果:拆除装置14 d后,实验组与对照组牙根吸收陷窝体积修复量分别为(0.0295±0.0052) ×1 07 μm3、(0.0189±0.0086)×107 μm3;牙移动后复发距离及复发百分率分别为(0.089±0.005)mm、(64.76±3.63)％和(0.127±0.010)mm、(92.28±1.90)％.统计学分析表明,拆除装置14 d后,牙根吸收陷窝体积修复量、牙移动后复发距离及复发百分率均有显著差异(P＜0.05).结论:一定浓度的釉基质蛋白衍生物可在一定程度上加强大鼠正畸移动后牙根吸收后修复效应,减弱牙移动后早期复发.     

正畸治疗后稳定性探讨

目的：探讨影响正畸治疗后稳定性的相关因素。方法：采用PAR（peer assessment rating)指数对74例错He畸形患者正畸治疗后2－8年（平均50．5个月）的治疗前后及保持后模型进行评估分析。结果：（1）保持后，加权总分值的复发率为13．01％，牙齿排列、覆盖、覆He和后牙段横向He关系复发率分别为6．38％、15．56％、28．36％和22．41％。（2）保持后明显改善者从治疗后77．03％减至64．86％。PAR分值增加53例，分值不变6例，分值减少15例。（3）Begg矫治器保持后加权总值大于方丝弓矫治器（P＜0．05）。（4）安氏Ⅱ类错He保持后牙排列和总分值大于I类错He（P＜0．05）。（5）不对称拔牙组保持后加权总分值大于其他组（P＜0．01）。结论：（1）保持停止后，牙齿有回复到原来位置的倾向。牙齿排列、覆盖、 覆He和后牙段横向He关系复发较明显。（2）正畸治疗后的稳定性与矫治器、错He及拔牙类型有关。     

影响正畸治疗后牙弓稳定性的相关因素探讨

目的　探讨影响正畸治疗后牙弓稳定性的相关因素。方法　对正畸治疗后 2 4～ 97个月 (平均 5 0 .0 5个月 ) 74例错牙合畸形患者治疗前后及保持后模型进行牙弓测量。结果　保持后 ,大部分测量项目男性大于女性 ,但减少百分率无显著差异 ;不同的矫治器类型 (除上下尖牙宽度P <0 .0 5外 )、错牙合类型 (除上牙弓长P <0 .0 1外 )和保持时间组间牙弓测量项目差异无显著性 (P >0 .0 5 ) ;保持后下 3- 3长度减少百分率非拔牙组 (13.4 4 % )和青少年组 (8.93% )分别大于拔牙组 (7.2 2 % )和成年组 (4 .10 % )。结论　保持停止后 ,尖牙间长度、宽度随着年龄的增大不断减少 ;下颌骨的向前生长和过度扩弓是导致下前牙拥挤复发的主要原因之一。     

错畸形治疗后前牙不齐指数的变化

目的　探讨牙列拥挤矫正后的稳定性及其相关因素。方法　选取由北京大学口腔医学院正畸科完成治疗 2年以上的患者 ,共 72例资料完整的病例。分别对其头颅侧位片与牙模型进行测量分析。结果　上前牙不齐指数均值由治疗前的 (11 5± 5 0 2 )mm减小至治疗后的 (2 0 1±1 39)mm ,随访时增加至 (3 4 6± 1 6 9)mm。下前牙不齐指数均值由治疗前的 (7 2 4± 4 35 )mm减小至 (1 75± 1 0 4 )mm ,随访时增加至 (3 39± 1 78)mm。治疗前后及治疗后至随访时差异均有显著性(P <0 .0 5 )。多元逐步回归统计显示 ,随访时颌骨矢状向 (Wits)和垂直向 (SGo/NMe)的变化以及下切牙位置 (L1 AP)、下颌尖牙间宽度 (L3W )的缩窄、全牙Bolton指数、性别因素均与随访时下前牙不齐指数的变化有显著相关性。结论　上前牙不齐指数在随访阶段的变化量大于下前牙 ;下前牙不齐指数在随访阶段的变化量与随访时颌骨矢状向和垂直向的变化、下切牙的位置、下尖牙间宽度、全牙Bolton指数及性别有关     

正畸应力作用下牙龈肌成纤维细胞表达的初步研究

目的 初步探讨正畸应力加载后牙龈肌成纤维细胞的表达情况。方法 选取8例正畸应力加载后需要拔除牙牙龈组织,以应力加载前拔除牙牙龈组织为对照,进行α-平滑肌肌动蛋白（α-SMA）、Ⅰ型胶原、Ⅲ型胶原免疫组织化学染色。然后进行测量和统计分析。结果 正畸应力加载前牙龈组织内Ⅰ型胶原、Ⅲ型胶原免疫组化染色阳性,α-SMA除血管上皮外,其余为阴性表达。正畸应力加载后,Ⅰ型胶原、Ⅲ型胶原表达明显上升,差异有统计学意义（P<0.05）;α-SMA在牙龈组织内出现阳性表达,与加力前差异有统计学意义（P<0.05）。结论 正畸应力加载后,牙龈组织内肌成纤维细胞出现表达,其可能在正畸牙术后复发中发挥一定作用。     

正畸应力作用下牙龈肌成纤维细胞表达的初步研究

目的 初步探讨正畸应力加载后牙龈肌成纤维细胞的表达情况。方法 选取8例正畸应力加载后需要拔除牙牙龈组织,以应力加载前拔除牙牙龈组织为对照,进行α-平滑肌肌动蛋白（α-SMA）、Ⅰ型胶原、Ⅲ型胶原免疫组织化学染色。然后进行测量和统计分析。结果 正畸应力加载前牙龈组织内Ⅰ型胶原、Ⅲ型胶原免疫组化染色阳性,α-SMA除血管上皮外,其余为阴性表达。正畸应力加载后,Ⅰ型胶原、Ⅲ型胶原表达明显上升,差异有统计学意义（P<0.05）;α-SMA在牙龈组织内出现阳性表达,与加力前差异有统计学意义（P<0.05）。结论 正畸应力加载后,牙龈组织内肌成纤维细胞出现表达,其可能在正畸牙术后复发中发挥一定作用。     

Utility of injectable bisphosphonates in enhancing orthodontic retention in a goat model: A split-mouth study

ObjectiveThe aim of this study was to evaluate the utility of bisphosphonates in reducing relapse after orthodontic tooth movement when injected intra-periodontally in a goat model.MethodsRight and left second incisors of four goats were extracted and the first and third incisors were approximated orthodontically and retained. A bisphosphonate gel was injected into the mesial and distal periodontal spaces of first and third incisors on one side, while the first and third incisors of the other side received normal saline as a control. After 12 weeks of retention, the orthodontic appliance was removed and teeth were relieved from any active force. Following 6 weeks from appliance removal, millimetric measurements were performed to calculate the amount of relapse of orthodontically moved incisors. Histological and microcomputed tomographic examination was performed to assess the periodontal space and surrounding alveolar bone of the study and control incisors.ResultsThe millimetric measurements and microcomputed tomographic scanning revealed that the orthodontically moved incisors in the side of bisphosphonate injection had significantly less relapse (p ≤ 0.05) and significantly narrower periodontal ligament width (p ≤ 0.05) than in the control side, respectively. Histologically, newly formed bone projecting into the periodontal ligament was observed in the side of bisphosphonate injection with newly formed cementum overlying areas of resorbed cementum.ConclusionThe results suggest that bisphosphonate injection has the potential to enhance post-orthodontic stability and repair of root resorption following orthodontic treatment.     

Aspects in post‐orthodontic removal of Orthosystem® implants

Objectives: Problems encountered in the removal of a temporary anchorage device, such as the Orthosystems implant, specially designed for orthodontic anchorage purposes after insertion at the palatal side of the maxilla, are presented and discussed. Material and methods: The removal of these osseo‐integrated implants was originally described to be executed by means of bone cutting around the implant with a trephine explanation burr. However, situations can be encountered in which the orthodontic tooth movement resulted in close contact between the implant and neighbouring teeth or the nasal cavity. Results: Trephine burr bone cutting around the implant can thereby lead to damage of the adjacent tooth with subsequent endodontic problems or perforation of the nasal cavity. In these cases, simple untightening by counterclockwise torque or if unsuccessful, removal of the transmucosal part of the fixture allowing creeping mucosal covering of the implant, should be considered. Furthermore, generation of CT‐scan images performed after completion of active orthodontic therapy, with retraction of the upper anterior teeth, seems to be justified and indicated for planning the appropriate removal procedure. Conclusion: Retrospectively, the use of the longer version of the Orthosystems implant (6 mm in length) seems to be obsolete when para‐median locations are chosen. Three cases are presented to illustrate these problems.     

青少年错畸形正畸治疗后前伸及侧方接触特征初探

目的研究青少年错畸形患者正畸后前伸及侧方接触特征。方法选择16例经正畸治疗获得正常牙列形态的青少年错畸形患者作为病例组,17名性别、年龄与病例组匹配的正常健康人作为对照组,使用T-ScanⅡ咬合分析系统记录2组受试者前伸及侧方运动,并比较2组的分离时间。结果病例组前伸及侧方干扰发生率较高, 干扰点多位于第二恒磨牙。病例组左侧方分离时间、右侧方分离时间及前伸分离时间分别为（1.504±0.681）、（1.532±0.913）、（1.358±0.791）s,对照组左侧方分离时间、右侧方分离时间及前伸分离时间分别为（0.470±0.059）、（0.483±0.045）、（0.482±0.047）s。病例组左侧方分离时间、右侧方分离时间及前伸分离时间均比对照组显著延长（P＜0.01）。结论与正常健康人相比,青少年错畸形患者正畸后前伸及侧方运动分离时间显著延长。     

Twelve-year follow-up of mandibular incisor stability: Comparison between two bonded lingual orthodontic retainers

Objective:To compare the long-term outcome 9 years after removal of two different types of fixed retainers used for stabilization of the mandibular anterior segment.Materials and Methods:Sixty-four children who had undergone orthodontic treatment with fixed appliances in both arches were divided into two groups depending on which kind of retainer being used. Twenty-eight of the patients had a canine-to-canine retainer bonded to the canines and 36 had a bonded twistflex retainer 3-3, bonded to each tooth. Measurements were made on study models and lateral head radiographs, before and after treatment, 6 years after treatment, and 12 years after treatment, with a mean of 9.2 years after removal of the retainers.Results:No significant differences were found between the two groups at the long-term follow-up according to Little''s Irregularity Index or available space for the mandibular incisors. The overjet and overbite were reduced after treatment in both groups and stayed stable throughout the observation period. Also, no differences in bonding failures between the two retainers were found.Conclusions:Both a canine-to-canine retainer bonded only to the canines and a twistflex retainer 3-3 bonded to each tooth can be recommended. However, neither of the retention types prevented long-term changes of mandibular incisor irregularity or available space for the mandibular incisors after removal of the retainers.     

Biomechanical effect of abutment on stability of orthodontic mini-implant. A finite element analysis

The biomechanical influences of primary factors on titanium mini-implant, which is used as an anchorage for orthodontic tooth movement, were quantified using the three-dimensional finite element method. Six types of finite element models were designed to show various thread pitches from 0.5 to 1.5 mm. Three models were designed with abutment and three other models without abutment. A traction force of 2 N was applied to the head of the mini-implant or abutment to be at 45 degrees to the bone surface. No remarkable differences were observed in the stress distribution patterns regardless of thread pitch variance. However, the stress distribution was remarkably different between models with abutment and without abutment. The maximum stress of the model with abutment and thread pitch 0.5 mm was the least as compared with the other models. Areas of high-level stress were obviously smaller than in the models without abutment. The plots of the displacement distributions of the models with abutment also presented significant pattern differences as compared with the models without abutment. The high-level area was localized to the head of the implant and the abutment in models with abutment. Therefore, the existence of the abutment is significantly useful in decreasing the stress concentration on the bone, while the effect of thread pitch was uncertain.     

Patient satisfaction after orthodontic treatment combined with orthognathic surgery: A systematic review

Objective:To synthesize available evidence about factors associated with patients’ satisfaction after orthodontic treatment combined with orthognathic surgery.Materials and Methods:Studies that evaluated any factor associated with patients’ satisfaction after the conclusion of an orthodontic treatment combined with an orthognathic surgery were identified. Orthognathic surgical procedures should have been undertaken after completion of craniofacial growth. Any satisfaction psychometric tool was considered. No language limitation was set. A detailed individual search strategy for each of the following bibliographic databases was crafted: MEDLINE, PubMed, EBM Reviews, Web of Science, EMBASE, LILACS, and Scopus. The references cited in the identified articles were also cross-checked, and a partial gray-literature search was undertaken using Google Scholar.Results:Eight articles satisfied the inclusion criteria of this systematic review and accounted for 998 patients. The included studies showed large variation in sample size (range  =  44 to 505 patients), age (range  =  15 to 72 years old), distinct psychological evaluation tools, and time elapsed between the assessment and the completion of surgery and postorthodontic treatment. Most of the studies (five of eight) were classified as having high risk of bias.Conclusion:Factors associated with satisfaction were final esthetic outcome, perceived social benefits from the outcome, type of orthognathic surgery, sex, and changes in patient self-concept during treatment. Factors associated with dissatisfaction were treatment length; sensation of functional impairment and/or dysfunction after surgery, and perceived omitted information about surgical risks.     

固定正畸后牙根吸收的部分影响因素分析

目的　研究影响正畸治疗后牙根吸收的部分临床因素。方法　随机选择经过固定正畸治疗 ,有清晰可辨的矫治前后全口曲面断层片者 96例。以改良根吸收分级法评估每名患者矫治前后全口牙齿根吸收情况。通过多元方差分析及多元回归分析 ,探讨正畸后平均根吸收值 (rootresorptionaftertreatment ,RRAT )与性别、年龄、减数与否、部位、疗程和治疗前平均根吸收值 (rootresorptionbeforetreatment,RRBT )的关系。结果　①女性RRAT校正均值为 0 4 1,男性为 0 34,差异有高度显著性 (P <0 .0 5 )。②拔牙组的RRAT校正均值为 0 4 3,未拔牙组为 0 31,差异有高度显著性(P <0 .0 0 1)。③前牙区RRAT校正均值为 0 5 9,后牙区为 0 12 ,差异有高度显著性。④上牙RRAT校正均值为 0 4 0 ,下牙为 0 37,差异无显著性。⑤RRAT与年龄、疗程及RRBT呈正相关 ,复相关系数R =0 5 9,判定系数R2 =0 35。结论　性别、年龄、减数与否、疗程、部位及治疗前牙根状况对正畸治疗后牙根吸收均有影响。