微种植体支抗同步分别内收前牙加速拔牙间隙关闭的临床研究

目的:探索微种植体支抗配合直丝弓矫治技术同步分别内收前牙加速拔牙间隙关闭的效果与机制.方法:23 例需强支抗的拔牙病例,使用微种植体支抗关闭拔牙间隙,自身随机对照设计,实验侧采用尖牙与切牙同步分别内收关闭拔牙间隙法(即除在后牙区的微螺钉种植体与前牙区的方丝牵引钩间用镍钛拉簧一步法关闭拔牙间隙外,还在微螺钉与尖牙间用橡皮链单独行尖牙远中移动);对照侧则只通过常规后牙区微螺钉种植体与前牙区的方丝牵引钩间用镍钛拉簧一步法关闭拔牙间隙.分别记录两侧拔牙间隙关闭所需的时间并观察前牙移动的位置和方式,SPSS 11.0统计软件对实验侧与对照侧拔牙间隙关闭所需的时间进行配对t检验.结果:实验侧拔牙间隙关闭时间平均(6.69±1.07)个月;对照侧拔牙间隙关闭时间平均(9.56±1.19) 个月;实验侧与对照侧比较差异有统计学意义(P<0.05).实验侧尖牙移动到位后具有更好的生理位置,而对照侧尖牙移动到位后较多发生牙冠远中舌向扭转.结论:微植体支抗配合直丝弓矫治技术同步分别关闭拔牙间隙,在缩短拔牙间隙关闭时间的同时,使尖牙能始终在松质骨中移动,因而前牙内收快,矫治效果相对更理想.     

两步法关闭拔牙间隙的问题

在正畸治疗中，关闭拔牙间隙有两种方法：一步法关闭或两步法关闭。后者可以减轻对支抗的消耗，而前者对支抗的消耗较高。本研究的目的在于比较两步法关闭拔牙间隙与一步法关闭拔牙间隙消耗支抗程度的不同。     

正畸关闭第一恒磨牙缺失间隙的支抗控制

第一恒磨牙是正畸矫治中的重要支抗单位。但很多正畸患者就诊时已经有一个或多个第一恒磨牙缺失或仅存留残冠残根。第一恒磨牙缺失后正畸治疗方案制定 ,支抗控制方法与常规治疗相比有何不同 ?本文通过对 15例错牙合病例进行回顾分析 ,现报告如下 :1　资料与方法1997～ 2 0 0 0年华西医科大学口腔医院就诊的错牙合畸形伴第一恒磨牙缺失的患者 ,共 15例 ,年龄 10～ 3 3岁 ,对缺牙间隙大小 ,部位 ,正畸治疗中采用的支抗控制方法 ,治疗完成后的间隙关闭情况等进行回顾总结。2　结　果15例第一恒磨牙缺失患者 ,上颌缺失 6个磨牙单位 ,下颌缺失磨…     

种植支抗关闭正畸拔牙间隙对上颌磨牙垂直向高度的影响

目的：研究种植支抗联合滑动法内收前牙间隙过程中上颌磨牙垂直向的改变。方法选择25例成人患者,根据治疗需要拔除上颌第一双尖牙,在上颌5、6之间植入种植钉,作为支抗内收前牙关闭间隙。将患者治疗前后的数字化模型进行重叠,比较上颌第一、第二磨牙的垂直向改变。结果上颌第一磨牙治疗后被压低（P<0.001）,第二磨牙没有明显改变。上颌第一磨牙的近中舌尖、远中舌尖、近中颊尖、远中颊尖四个牙尖的改变无显著性差异。结论使用种植支抗联合滑动法关闭正畸拔牙间隙,将会导致上颌第一磨牙的压低,但是第二磨牙没有显著改变,并且第一磨牙没有明显的颊侧倾斜。     

种植单冠支抗关闭牙列间隙一例

牙列缺损后可出现散在间隙,影响与对颌牙的咬合关系,并降低牙列的稳定性,引起食物嵌塞。作者利用种植支抗先关闭牙列间隙,然后将支抗种植体改为牙种植体,行种植义齿修复散在间隙的邻近牙列缺损一例。现介绍如下。患者张某某,男性,３８岁,大学教师,｜６缺失５年,...     

自锁托槽结合种植支抗对关闭拔牙间隙速度影响的实验研究

目的:在Typodont模型上,模拟临床应用自锁托槽结合微种植体支抗关闭拔牙间隙的过程,研究新方案对关闭间隙速度的影响。方法:制作24个安氏I类双颌牙齿前突的标准Typodont模型,随机分成实验组和对照组各12个。实验组使用自锁托槽结合微种植体支抗牵引关闭拔牙间隙,牵引力为75g;对照组则使用直丝弓托槽结合口外弓支抗关闭拔牙间隙,牵引力为150g。结果:实验组的平均间隙关闭速度为(1.37±0.03)mm/h,显著高于对照组的(0.87±0.03)mm/h(P<0.001)。实验组的上颌中切牙平均舌侧移动距离为(6.27±0.44)mm,显著大于对照组的(4.34±0.38)mm(P<0.001)。实验组的上颌第一磨牙平均近中移动距离为(0.11±0.08)mm,显著小于对照组的(2.34±0.24)mm(P<0.001)。结论:应用自锁托槽结合微种植体支抗关闭拔牙间隙速度显著快于传统的直丝弓托槽结合口外弓支抗,支抗丧失更少。     

直丝弓一步和两步滑动法的比较研究

本研究利用三维坐标测量仪,开发了正畸牙移动的上颌测量系统,并采用前瞻性配对设计,对１６例拔除四个第一双尖牙,使用国产Ｒｏｔｈ数据直丝弓矫治器矫治的病例,分两组分别进行一步滑动法和两步滑动法关闭间隙。测量研究的结果显示;两步法在节省支抗上要稍优于一步法,但临床上不显著,一步法在时间上要明显短于两步法,两才在维持覆Ｈｅ,维持前牙转矩方面无显著差别。     

正畸关闭成人第一恒磨牙缺失间隙的临床疗效

目的研究正畸方法关闭成人第一恒磨牙早失或者拔除间隙的疗效及其影响因素。方法成人正畸患着19例,第一恒磨牙早失11颗（磨牙早失组）,其中5颗第二恒磨牙治疗前存在附着丧失;第一恒磨牙严噩龋齿被拔除16颗（磨牙拔除组）,其中5颗第二恒磨牙治疗前存在附着丧失。两组均应用直丝弓矫治技术,治疗前后拍摄全景片,治疗前后和关闭间隙前后检查第二恒磨牙牙龈指数和附着丧失,使用SPSS13．0软件进行双因素方差分析,因素1为治疗前第二恒磨牙有无附着丧失（有为牙用炎组,无为牙周健康组）,因素2为第一恒磨牙缺失是由于拔除或早失。结果磨牙间隙完全关闭,牙龈指数较治疗前改善。磨牙早失组较磨牙拔除组的间隙关闭疗程长,第二恒磨牙附着丧失量较多;牙周炎组较健康牙周组疗程短（P〈0．05）,第二恒磨牙附着丧失量更多。各因素对间隙关闭速度和治疗后第二恒磨牙附着丧失量的影响贡献从大到小为：治疗前第二恒磨牙附着匙失与否、磨牙早失或拔除、两者交互效应。结论通过正畸方法关闭成人第一恒磨牙缺失间隙,甚至骨缺损间隙足可行的．治疗前附着丧失的程度和牙周炎的易感程度是治疗效果的重要影响因素。     

正畸关闭下颌第一恒磨牙缺失间隙的疗效观察

目的探讨正畸关闭下颌第一恒磨牙缺失间隙的疗效和矫治特点。方法选取16例下颌第一恒磨牙拔除超过1年以上的患者,与患者充分沟通后采用直丝弓矫治技术关闭缺牙间隙,观察疗效并分析矫治特点。结果16例患者均在19～26个月完成正畸治疗,所有患者第一恒磨牙缺失间隙关闭,前牙覆验覆盖正常,尖牙中性关系,磨牙为尖窝交错关系。软组织侧貌协调,患者对治疗效果满意。结论正畸法关闭第一恒磨牙缺失间隙可取得较好的临床治疗效果。     

成年人第一磨牙拔牙间隙变化的临床研究

目的观察拔牙方法对第一磨牙拔牙间隙变化的影响,分析拔牙间隙变化的原因和预防办法。方法选择44例需拔除第一磨牙的患者作为研究对象,分成3组,A组17例,拔牙后不作特殊处理。B组15例,对患牙近、远中邻牙调牙合后再拔牙。C组12例,拔牙后戴用可摘过度性义齿。分别测量各组患者拔牙后30 min、3个月时拔牙间隙的近、远中方向最小径,比较分析各组间拔牙间隙变化的情况。结果拔牙后30 min与拔牙后3个月比较,A组拔牙间隙有显著性减小(P<0.001)。B组和C组拔牙间隙都无显著性改变(P>0.05)。结论拔牙后3个月内,调牙合和过渡性义齿修复均可阻止第一磨牙拔牙间隙的减小,有利于维持拔牙后牙列稳定。     

Comparison of anterior retraction and anchorage control between en masse retraction and two-step retraction: A randomized prospective clinical trial

Objectives:The purpose of this two-arm parallel trial was to compare en masse (ER) and two-step retraction (TSR) during space closure.Materials and Methods:Forty-eight adult patients with bimaxillary protrusion who were planned for treatment with extraction of four first premolars were enrolled. All patients were randomly allocated in a 1:1 ratio to either the ER (n = 24) group or the TSR (n = 24) group. The main outcome was the amount of posterior anchorage loss in the molars and the retraction of the incisors between ER and TSR; the difference in incisor and molar inclination was a secondary outcome. Lateral cephalometric radiographs and oblique cephalometric radiographs at 45° were taken before retraction (T1) and after space closure (T2). Cephalograms were digitized and superimposed on the anatomic best fit of the maxilla and mandible by one operator who was blinded to the treatment group.Results:Neither incisor nor molar crown movements showed any significant differences between the ER and TSR. There were no significant differences in the tipping of incisors and molars between the two groups.Conclusions:No significant differences existed in the amount of retraction of incisors and anchorage loss of molars between ER and TSR. Changes in incisor and molar tipping were similar, with the crowns showing more movement than the apex.     

Tooth movement rate and anchorage lost during canine retraction: A maxillary and mandibular comparison

Objectives:To investigate the canine retraction rate and anchorage loss during canine retraction using self-ligating (SL) brackets and conventional (CV) brackets. Differences between maxillary and mandibular rates were computed.Materials and Methods:Twenty-five subjects requiring four first premolar extractions were enrolled in this split-mouth, randomized clinical trial. Each patient had one upper canine and one lower canine bonded randomly with SL brackets and the other canines with CV brackets but never on the same side. NiTi retraction springs were used to retract canines (100 g force). Maxillary and mandibular superimpositions, using cephalometric 45° oblique radiographs at the beginning and at the end of canine retraction, were used to calculate the changes and rates during canine retraction. Paired t-tests were used to compare side and jaw effects.Results:The SL and CV brackets did not show differences related to monthly canine movement in the maxilla (0.71 mm and 0.72 mm, respectively) or in the mandible (0.54 mm and 0.60 mm, respectively). Rates of anchorage loss in the maxilla and in the mandible also did not show differences between the SL and CV brackets. Maxillary canines showed greater amount of tooth movement per month than mandibular canines (0.71 mm and 0.57 mm, respectively).Conclusions:SL brackets did not show faster canine retraction compared with CV brackets nor less anchorage loss. The maxillary canines showed a greater rate of tooth movement than the mandibular canines; however, no difference in anchorage loss between the maxillary and mandibular posterior segments during canine retraction was found.     

Effect of piezocision corticotomy on en-masse retraction:: A randomized controlled trial

ObjectivesTo compare the amount of en-masse retraction with or without piezocision corticotomy, to assess the type of tooth movement, to evaluate root integrity after retraction, and to record reported pain levels.Materials and MethodsThis randomized, controlled clinical trial included 26 orthodontic patients requiring premolar extraction. The patients were divided into two groups: (1) an extraction with piezocision corticotomy group (PCG) and (2) an extraction-only group, which served as the control group (CG). Cone-beam computed tomography images were acquired before and 4 months after the initiation of en-masse retraction utilizing miniscrews. The following variables were assessed: the amount of en-masse retraction, incisor inclination, incisor and canine root resorption, and patient-reported pain.ResultsTwelve and 11 participants completed the entire study in the PCG and CG, respectively. The amount of en-masse retraction was significantly greater in the PCG compared to the CG (mean = 4.8 ± 0.57 mm vs 2.4 ± 0.33 mm, respectively [P < .001]). There was also significantly less tipping and root resorption of incisors in the PCG (P < .05). The reported pain was significantly higher on the first day in the PCG compared to the CG (P < .001); however, it became similar between the groups after 24 hours.ConclusionsPiezocision corticotomy enhanced the amount of en-masse retraction two times more with less root resorption. However, future studies are required to assess the long-term effects of this technique.     

Canine retraction and anchorage loss: Self-ligating versus conventional brackets in a randomized split-mouth study

Objective:To evaluate the velocity of canine retraction, anchorage loss and changes on canine and first molar inclinations using self-ligating and conventional brackets.Materials and Methods:Twenty-five adults with Class I malocclusion and a treatment plan involving extractions of four first premolars were selected for this randomized split-mouth control trial. Patients had either conventional or self-ligating brackets bonded to maxillary canines randomly. Retraction was accomplished using 100-g nickel-titanium closed coil springs, which were reactivated every 4 weeks. Oblique radiographs were taken before and after canine retraction was completed, and the cephalograms were superimposed on stable structures of the maxilla. Cephalometric points were digitized twice by a blinded operator for error control, and the following landmarks were collected: canine cusp and apex horizontal changes, molar cusp and apex horizontal changes, and angulation changes in canines and molars. The blinded data, which were normally distributed, were analyzed through paired t-tests for group differences.Results:No differences were found between the two groups for all variables tested.Conclusions:Both brackets showed the same velocity of canine retraction and loss of anteroposterior anchorage of the molars. No changes were found between brackets regarding the inclination of canines and first molars.     

Analysis of canine retraction and anchorage loss in different facial types with and without piezocision: a split-mouth–design,randomized clinical trial

ObjectivesTo investigate canine retraction (CR) and anchorage loss (AL) among average facial height (AFH) and high facial height subjects (HFH) with or without piezocision surgery (PS).Materials and MethodsThis was a split-mouth, randomized clinical trial. Twenty-three females (aged 19.05 ± 2.95 years) who presented with Class II division I malocclusion requiring bilateral maxillary extraction and who fulfilled eligibility criteria were included and categorized into two groups: AFH (12 participants) and HFH (11 participants). Atraumatic extractions were performed 10 weeks following bonding. Before space closure, impressions were taken to fabricate models, which were scanned to generate digital models. Each participant had PS on the randomly assigned side. Space closure was undertaken using 100-g nickel-titanium coil closing springs on 0.019 × 0.025-inch stainless steel archwire. Digital models were collected 6 and 12 weeks post-PS. They were superimposed using reliable reference points and a region of interest on the palate, and crown movements were analyzed in three dimensions.ResultsThree months post-PS, intergroup comparisons showed that rates of CR for control sides (mean = 1.88 ± 0.83 mm for AFH, mean = 1.76 ± 0.62 mm for HFH) and intervention sides (mean = 1.48 ± 0.74 mm for AFH, mean = 1.40 ± 0.85 mm for HFH) were not significantly different. AL was not significantly different (P > .05) between groups.ConclusionRegardless of whether the patient underwent PS, CR and AL rates for AFH and HFH patients were not significantly different.     

Mechanical environment for lower canine T-loop retraction compared to en-masse space closure with a power-arm attached to either the canine bracket or the archwire

ObjectivesTo assess the mechanical environment for three fixed appliances designed to retract the lower anterior segment.Materials and MethodsA cone-beam computed tomography scan provided three-dimensional morphology to construct finite element models for three common methods of lower anterior retraction into first premolar extraction spaces: (1) canine retraction with a T-loop, (2) en-masse space closure with the power-arm on the canine bracket (PAB), and (3) power-arm directly attached to the archwire mesial to the canine (PAW). Half of the symmetric mandibular arch was modeled as a linear, isotropic composite material containing five teeth: central incisors (L1), lateral incisor (L2), canine (L3), second premolar (L4), and first molar (L5). Bonded brackets had 0.022-in slots. Archwire and power-arm components were 0.016 × 0.022 in. An initial retraction force of 125 cN was used for all three appliances. Displacements were calculated. Periodontal ligament (PDL) stresses and distributions were calculated for four invariants: maximum principal, minimum principal, von Mises, and dilatational stresses.ResultsThe PDL stress distributions for the four invariants corresponded to the displacement patterns for each appliance. T-loop tipped the canine(s) and incisors distally. PAB rotated L3 distal in, intruded L2, and extruded L1. PAW distorted the archwire resulting in L3 extrusion as well as lingual tipping of L1 and L2. Maximum stress levels in the PDL were up to 5× greater for the PAW than the T-loop and PAB methods.ConclusionsT-loop of this type is more predictable because power-arms can have rotational and archwire distortion effects that result in undesirable paths of tooth movement.     

上颌第一磨牙与第二磨牙牙根融合1例

融合牙是牙齿形态发育异常中的一种,主要发生于前牙区,后牙区相对少见,本文报道上颌第一磨牙与第二磨牙牙根融合1例,为临床同行提供参考。     

微型种植体支抗压低上前牙的临床应用

目的观察微型种植体支抗压低上前牙的临床疗效,评价其压低上前牙的有效性。方法选择6例高角或高角倾向伴前牙Ⅲ°深覆,上颌前部牙槽发育过度,上唇与上前牙关系严重不调的患者,平均年龄24.4±1.4岁,采用微型种植体作支抗,在两侧上侧切牙牙根和尖牙牙根间牙槽骨唇侧植入,每侧以50克的牵引力压低上前牙。测量治疗前后X线头颅定位侧位片,包括6-PP距的改变量、上中切牙压低量和转矩改变量。结果6-PP距的变化均值为0.27±0.05mm,无统计学意义(P>0.05),上中切牙平均压低6.12±0.16mm,临床牙冠平均缩短0.66±0.05mm。治疗过程中微型种植体无松动和脱落。结论用微型种植体作支抗压低上前牙,操作简单,异物感不明显,上前牙明显压低,效果良好。