替牙期正畸治疗对上中切牙牙根发育的影响

目的 探讨替牙列期正畸治疗对上中切牙牙根发育的影响.方法 对178例来我院就诊的替牙期错(牙合)畸形儿童进行追踪调查.根据治疗前上中切牙牙根发育状况,分为牙根发育小于1/2组、牙根发育大于1/2但根尖孔未闭合组及牙根发育完成组,以牙根发育完成组作为空白对照组.治疗结束后拍全景X线片对牙根发育情况进行追踪观察,直至牙根发育停止,对牙根发育状况进行评估,分析正畸治疗对上中切牙牙根发育的影响.结果 牙根发育小于1/2组的108颗上中切牙中,发生短根或喇叭口根尖的共18颗,与牙根发育大于1/2但根尖孔未闭合组和牙根发育完成组相比,牙根发育小于1/2组的上中切牙更易发生短根或喇叭口根尖,组间差异有统计学意义.结论 在替牙期错(牙合)畸形正畸治疗中,上中切牙牙根发育小于根长1/2时,易受正畸力的影响形成短根或喇叭口根尖.     

猫下颌尖牙根管治疗对牙正畸移动的影响

目的：探讨经根管治疗牙的正畸移动可行性及牙根吸收的风险.方法：建立对经根管治疗牙进行正畸移动的动物模型,采用石膏模型测量、病理学和放射学方法评估正畸移动的距离及牙根吸收的程度.16只成年家猫的一侧下颌尖牙在全麻下开髓、拔髓,一次完成根管充填治疗术,随后在正畸弹簧的作用力（100～120 g）下向远中作倾斜移动.8周后测量石膏模型上牙移动的距离,以及根管治疗牙与正常牙的组织学和放射学牙根长度.应用SPSS11.0软件包进行数据分析,均数比较采用配对t检验.结果：实验结果显示,在相同正畸力作用下,根管治疗牙与正常牙移动距离相近（P＞0.05）;组织病理学显示,根管治疗牙牙根的长度比正常牙小（P＜0.05）,但在放射学上,两者的长度无统计学差异（P＞0.05）.结论：在本实验条件下,经根管治疗牙在正畸力作用下能与正常牙同样快速移动,组织学观察显示其根吸收的程度比后者略大.     

青少年正畸治疗中影响牙根吸收的因素探讨

目的：探讨影响青少年错[牙合]畸形患者正畸矫治后牙根吸收的相关因素。方法：选择已完成正畸固定矫治的青少年患者78例．在其矫治前后的曲面断层片上,对4个上切牙进行根尖形态的分析,以获得正畸矫治后牙根吸收的定性数据。在对受试者按年龄、性别、牙位、牙龄、拔牙与否及疗程分组后,利用SPSS12．0软件对所得数据进行非参数检验分析。结果：所有正畸患者都存在一定程度的牙根吸收,根尖形态分析显示：①牙龄ⅣA期患者比ⅢC期的患者存在更严重的牙根吸收（P〈0．01）,但按年龄比较不存在显著差异;②拔牙组比不拔牙组有更加严重的牙根吸收（P〈0．01）;③疗程越长,牙根吸收也越明显（P〈0．05）;④牙根吸收的严重程度与性别及上切牙牙位之间无相关性。结论：在第二恒磨牙完全建验前（ⅣA期前）进行正畸治疗、不拔牙矫治、缩短矫治疗程,均可以减少正畸治疗中的牙根吸收。     

牙体牙髓-正畸方法联合处理恒上前牙冠根折的临床观察

目的：观察牙体牙髓－正畸方法联合处理恒上前牙冠根折的临床疗效。方法：21颗冠根折的恒上前牙，在完善根充后，利用正畸方法对患牙牙根进行垂直He向牵引，达到理想牙冠修复条件，在此基础上进行牙冠延长术和修复治疗。结果：21颗患牙垂直He向移动距离2mm-5mm，所需时间4周－8周；三年复查，部分患牙牙齿或牙龈相对位置有轻微变化，所有患牙根尖周正常。结论：牙体牙髓－正畸方法联合处理恒上前牙冠根折，作为修复治疗的辅助方法有效可行，但18岁以下的患者需延长牵引后的保持时间，并用临时冠进行过渡性修复。     

正畸治疗与牙根吸收

牙根吸收是正畸治疗中最敏感的问题之一,本文介绍了与正畸牙根吸收有关的因素、好发牙位、临床上诊断牙根吸收的方法及预防牙根吸收的方法,指出牙根吸收问题是一个与技术方法及个体组织反应有关的问题。     

Ⅰ类和Ⅱ类错(牙合)拔牙治疗中的根尖吸收评估

为确定正畸治疗中牙根的吸收量和牙齿移动与根吸收之间的关系,选取两组病例,每组均由27例(16女,11男)组成。第一组为Ⅰ类前牙拥挤的错(牙合),第二组为Ⅱ类Ⅰ分类伴覆盖大的错(牙合)。两组患者均为恒牙列,拔除4个第一双尖牙后,用方丝弓固定矫治器治疗。收集治疗前后的头影测量片,测量项目有:①U_1PP距,②U_1-FH°,③U_1-AP°,④U_1-AP距,⑤U_1切端-PTV距,⑥U_1根尖-PTV距,⑦U_1长度。 结果显示:治疗前后比较Ⅰ类患者很尖吸收量平均约为1mm(P<0.01),Ⅱ类患者的根尖吸收量平均     

面型对正畸支抗牙牙根吸收影响的临床研究

目的 探讨不同面型在正畸治疗中对支抗牙牙根吸收的影响。方法 选择120例经方丝弓矫治器治疗的患者,按面型分为高角型、正常型、低角型3个组,每组患者治疗前后分别拍摄头颅侧位定位片,配对测量分别被确定作为支抗的后牙或前牙正畸治疗前后牙根长度,将牙根长度改变量以计算机进行统计分析,并评价牙根吸收情况。结果3组病例正畸治疗前后支抗牙牙根长度改变有统计学意义(P<0.001)。3组之间相对应牙齿的牙根吸收量不同,高角型病例牙根吸收轻,而低角型病例牙根吸收重。组间不同的吸收量差异有统计学意义(P<0.01)。结论 在正畸治疗中不同面型对支抗牙牙根吸收程度有不同影响,面型是影响支抗牙牙根吸收的一个重要因素。     

上前牙唇倾改向美容烤瓷修复

上前牙唇向倾斜是临床上常见的一种牙列错牙合畸形。上前牙唇倾可由遗传、不良习惯、牙周病变、错牙合牙等原因造成 ,患者表现为上前牙前突 ,嘴唇不易闭合呈“开唇露齿”状。这种现象不仅有碍于患者的准确发音 ,更有损于患者的容貌及形象。笔者近年在临床上采用患牙改向美容烤瓷修复的方法 ,曾为无条件作正畸治疗的 36位成年人上前牙唇向倾斜患者进行修复治疗 ,取得较好疗效 ,现介绍如下。1　适应证1.1　 18岁以上牙根已发育完成 ,无条件作正畸治疗或希望快速改善面部形象者。1.2　有牙髓及根尖周病变 ,但已经过完善的牙髓及根管治疗经 1～ …     

正畸治疗对根管治疗牙及对侧同名活髓牙根吸收影响的Meta分析

目的    分析正畸治疗对根管治疗牙及对侧同名活髓牙根吸收的影响。方法    计算机检索Cochrane Library、PubMed、Embase、Google Scholar、中国知网、万方等数据库,查找研究根管治疗牙经正畸治疗后牙根吸收情况的相关文献。应用Meta分析比较正畸治疗对根管治疗牙及对侧同名活髓牙根吸收的影响。结果    纳入了10篇相关文献。Meta分析结果发现,正畸治疗患者根管治疗牙根吸收情况与对侧同名活髓牙比较,差异无统计学意义（P > 0.05）。在男性正畸治疗患者中,根管治疗牙牙根吸收量小于对侧同名活髓牙,差异有统计学意义（P < 0.05）;而女性正畸治疗患者两侧牙根吸收量比较,差异无统计学意义（P > 0.05）。正畸治疗方式（拔牙矫治与非拔牙矫治）和牙位（前牙与后牙）对正畸治疗患者根管治疗牙及对侧同名活髓牙根吸收的影响比较,差异均无统计学意义（均P > 0.05）。结论    正畸治疗过程中移动根管治疗后的牙齿是一种相对安全的操作。     

成人骨性Ⅲ类错牙合患者正畸去代偿前后下切牙区牙槽骨形态特征的CBCT研究

目的比较正畸去代偿前后严重的成人骨性Ⅲ类错牙合患者下切牙区牙槽骨形态变化情况。方法对15例接受正畸-正颌联合治疗的严重成人骨性Ⅲ类错牙合患者(男9例,女6例,平均年龄23.6岁),分别在治疗前(T0期)和正颌手术前1个月(T1期)进行CBCT摄片。分别测量正畸前及术前正畸结束时下切牙区牙槽骨形态,包括牙槽骨厚度、牙槽骨附着高度、牙根长度等指标。相关数据采用SPSS15.0统计软件进行配对t检验。结果正畸去代偿前后的比较结果显示:1正畸去代偿以后下切牙唇倾度增大,根尖点距舌侧骨皮质距离变小(P<0.01);2牙槽骨厚度未见明显改变;3唇舌侧牙槽骨附着高度矫治后均有降低,尤其是舌侧牙槽骨附着高度降低显著(P<0.01);4牙根长度测量未见明显改变。当下切牙进行较大范围的唇向倾斜运动时,牙根向舌侧骨皮质靠近,牙槽骨附着高度进一步降低。结论在成人骨性Ⅲ类错牙合的矫治中,由于需要在不良的牙槽骨形态中移动下切牙,必须密切关注其牙周组织状况、牙槽骨形态变化以及牙根与牙槽骨的关系,选择恰当的矫治方案,减少下切牙过度地唇舌向移动,避免不良反应的发生。     

Volumetric cone-beam computed tomography evaluation and risk factor analysis of external apical root resorption with clear aligner therapy

ObjectivesTo investigate the prevalence and severity of external apical root resorption (EARR) volumetrically with clear aligner therapy using cone-beam computed tomography (CBCT) as well as determine the possible risk factors and develop a prediction model for EARR.Materials and MethodsIn this retrospective study, 320 incisors from 40 Class II patients treated with aligners (Invisalign) were included in this study. CBCT images were obtained at pretreatment (T0) and posttreatment (T1). Root volume was calculated by three-dimensional reconstruction of CBCT images, and apical tooth movement was measured from superimposed CBCT images. Changes in root volume were compared using paired t-tests, and the relationship between root volume loss and potential risk factors was analyzed by multiple linear regression.ResultsAll of the measured incisors showed root volume loss, with an average of 11.48 ± 6.70 mm³, and the prevalence of severe resorption was 0.625%. The prediction model for EARR included variables of posttreatment sagittal root position (SRP), extraction, tooth type, and apical intrusion and extrusion displacements, with an R² of 0.51. Age, sex, duration, pretreatment SRP, attachment, advancement, and retraction movements were excluded from the model.ConclusionsMost incisors showed mild to moderate resorption during aligner treatment; only a minimal percentage showed severe resorption. Posttreatment SRP (which showed the highest association with EARR), extraction, tooth type, and apical intrusion and extrusion displacements were risk factors for EARR.     

Evaluation of apical root resorption following extraction therapy in subjects with Class I and Class II malocclusions

The purpose of this study was to determine the amount of root resorption during orthodontic treatment, and to examine the relationship between tooth movement and apical root resorption. Twenty-seven Class I and 27 Class II patients treated with edgewise mechanics following first premolar extractions were selected. The following measurements were made on the pre- and post-treatment cephalograms: upper central incisor to palatal plane distance, the inclination of upper central incisor to the FH and AP planes, the perpendicular distances from the incisor tip to the AP and PTV planes, and incisor apex to PTV. The amount of apical root resorption of the maxillary central incisors was determined for each patient by subtracting the post-treatment tooth length from the pre-treatment tooth length measured directly on cephalograms. Intra-group differences were evaluated by the Student's t-test and inter-group differences by the Mann-Whitney U-test. For correlations the Pearson correlation coefficient was used. The results show that there was a mean of approximately 1 mm (P < 0.01) of apical root shortening in Class I patients, but in Class II division I subjects the mean root resorption was more than 2 mm (P < 0.001). The inter-group differences were statistically significant. No significant correlations were found between the amount of apical root resorption and tooth inclination, or the duration of active treatment.     

新型无磨料牙膏对聚甲基丙烯酸甲酯树脂表面性能影响的研究

 目的　研制新型无磨料牙膏，并评估其对聚甲基丙烯酸甲酯（polymethyl methacrylat，PMMA）树脂表面性能的影响。方法　在新型牙膏中去除磨料并调整表面活性剂和湿润剂的比例，对10种新型牙膏的性状进行评估；选择较佳性状的2种新型牙膏（新型牙膏A组和新型牙膏B组）与市面牙膏（市面牙膏A组和市面牙膏B组）、市面泡腾片（市面泡腾片组）及蒸馏水（对照组）对PMMA树脂片进行清洁处理，比较各组清洁前后PMMA树脂片表面光密度（OD）值及粗糙度（Ra）值，评估各类清洁剂对PMMA树脂表面清洁效果及磨损水平。结果　10种新型牙膏中2号（新型牙膏A组）和6号（新型牙膏B组）具有较佳的性状，其pH值分别为7.18和7.22，并用于后续研究。（1）清洁效果：对照组清洁处理前后PMMA树脂片菌斑红染及OD值基本无明显变化，差异无统计学意义（P > 0.05），其余各组清洁处理后的PMMA树脂片菌斑红染程度较清洁处理前明显降低，OD值也显著下降，差异有统计学意义（均P < 0.05），尤其以市面泡腾片组、新型牙膏A组和新型牙膏B组清洁效果最为显著。（2）磨损水平：体视显微镜观察发现，清洁处理后，对照组PMMA树脂片表面光滑无划痕；市面牙膏A组和市面牙膏B组PMMA树脂片表面划痕较深且划痕数量较多，Ra值也明显增大，差异均有统计学意义（均P < 0.05）；市面泡腾片组、新型牙膏A组和新型牙膏B组PMMA树脂片表面仅出现轻微细小浅划痕，Ra值略微升高，但其差异均无统计学意义（均P > 0.05）。结论　新型无磨料牙膏在有效清除菌斑软垢的同时可减少PMMA树脂表面划痕，可成为临床义齿清洁牙膏。     

骨皮质切开术辅助上切牙内收后对牙根及牙槽骨影响的锥形束CT研究

目的 探讨骨皮质切开术辅助上切牙内收后对上颌切牙牙根吸收、牙槽骨厚度和牙槽骨高度的影响.方法 招募20例拔除两个上颌第一前磨牙的骨性Ⅱ类1分类错牙合畸形患者,分为骨皮质切开术组(n=10)和对照组(n=10).矫治前后拍摄锥形束CT,测量两组矫治前后上颌切牙牙根长度、牙槽骨厚度和牙槽骨丧失高度.结果 骨皮质切开术组矫治...     

Volumetric evaluation of root resorption on the upper incisors using cone beam computed tomography after 1 year of orthodontic treatment in adult patients with marginal bone loss

Objectives:To determine upper incisor root resorption, volume loss, and the relationship between root volume loss and tooth movement after 1 year of orthodontic treatment in patients with marginal bone loss.Materials and Methods:A total of 30 women (46.3 ± 5.4 years old) with moderate upper incisor bone loss who required intrusion during orthodontic treatment were recruited. Pre- and post-treatment cone beam computed tomography images were reconstructed. Upper incisors at pre- and post-treatment were superimposed; labio- and palato-apical, middle, and coronal third root volumes were assessed. Tooth movement and alveolar bone height were measured from lateral cephalometric radiographs and cone beam computed tomography. Changes in root volume/alveolar bone height were compared using paired-sample t-tests, percentage root volume loss for each tooth/segment was evaluated by one-way analysis of variance, and the relationship between percentage root loss and degree of tooth movement was assessed by linear regression.Results:Mean root volume significantly decreased on the labio- and palato-apical aspects of 12 and labio-apical aspects of 21 and 22 (P ≤ .024). Palato-apical segment volume loss was greater on lateral than central incisors (P ≤ .016). Two-dimensional root length and cementoenamel junction-bone crest distance did not change between T0 and T1, with no significant relationship between tooth movement amount and percentage root volume loss.Conclusions:Delivery of 40 g intrusive force to the four upper incisors using a T-loop and the leveling phase lead to more apical root volume loss on lateral than central incisors. There was no relationship between extent of tooth movement and upper incisor root volume loss.     

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目的采用三维有限元法模拟不同方向牵引力内收上前牙,分析前牙位移趋势及应力分布,为临床治疗提供指导。方法研究于2012年在福建医科大学进行。建立唇侧直丝弓矫治器、6个上前牙及其牙周膜和前颌骨的三维有限元模型。模拟在0.48 mm×0.64 mm英寸主弓丝上,以种植钉为支抗、1.47 N矫治力整体内收上前牙,设定前牙区牵引钩为0-6 mm、后牙区种植钉高度分别为8和14 mm。加载后求解,计算出各前牙的位移及牙周膜第一主应力。结果滑动法整体内收上前牙时,牵引钩长度主要影响前牙的矢状向位移方式：牵引钩长度增加至6 mm的过程中,侧切牙在唇舌向上由舌向倾斜运动变为舌向整体平移和舌向控根运动外,中切牙和尖牙的三维位移只有数量的增大,趋势基本保持不变。支抗种植钉高度主要影响前牙垂直向位移：种植钉位置越高,侧切牙的压低位移增大,尖牙的伸长位移减小,即前牙整体压低的趋势更明显。结论种植支抗整体内收前牙时,单纯调整牵引钩长度和支抗种植钉高度难以实现前牙段的整体内收,有必要对前牙段增加适当的垂直向压低力量。     

Ⅱ类1分类错[牙合]正畸治疗前后牙齿移动与软组织侧貌变化的线性相关分析

目的通过对Ⅱ类1分类错[牙合]患者正畸治疗前后的头影测量指标进行相关性分析,探讨影响面部软组织侧貌变化的相关因素。方法选取2012年6月至2017年11月于上海交通大学医学院附属第九人民医院口腔颅颌面科就诊的42例已完成正畸治疗的Ⅱ类1分类错[牙合]患者[男性10例,女性32例,年龄(23.8±6.3)岁,平均矫治时间1.9年],拔除4颗第一前磨牙或2颗上颌第一前磨牙后进行正畸治疗纠正磨牙关系,测量矫治前后硬组织及软组织相关头影测量指标30个,包括上下唇突点、颏唇沟点、软硬组织颏前点及颏顶点的矢状向及垂直向距离、鼻唇角及颏唇角等。对矫治前后各指标变化量进行线性回归分析,根据标准化回归系数(Beta)分析影响上下唇、鼻唇角、颏唇角等面部软组织的主要相关因素。结果30个头影测量指标中18个矫治前后差异均有统计学意义(P<0.05),与矫治前相比,矫治后上中切牙点矢状向距离[(63.87±7.14)mm]、上唇突点矢状向距离[(77.73±7.60)mm]显著减小(P<0.05)。14对头影测量指标变化量间存在线性关系,其中上唇突点矢状向变化量与上中切牙点矢状向变化量强正相关(r=0.649,P<0.01),上唇突点垂直向变化量与上中切牙点垂直向变化量中度正相关(r=0.544,P<0.01),软组织颏顶点矢状向变化量与Y轴角变化量中度负相关(r=0.537,P<0.01)。多元逐步后退回归分析显示,上唇突点内收量与上中切牙点内收量、平面角增大量以及上中切牙角增大量均相关,且与上中切牙点内收量相关性最大(Beta=0.79);上唇突点下移量与上中切牙点下移量、上中切牙角减小量、上颌第一磨牙面中点到腭平面距离减小量以及平面角增大量相关,且与上中切牙点下移量及平面角增大量的相关性最大(Beta均为0.59);下唇突点下移量与上、下中切牙点下移量相关,且与上中切牙点下移量相关性更大(Beta=0.36)。结论Ⅱ类1分类错[牙合]矫治后鼻唇颏关系得到一定改善,切牙的矢状向变化对唇突度的影响最大,且下唇矢状向与垂直向移动与上中切牙的位置关系更密切,牙齿移动对颏部的影响有限。     

Root resorption associated with ectopically erupting maxillary permanent canines: a computed tomography study

The aims of this retrospective computed tomography (CT) study were to determine the occurrence of severe root resorption involving the pulpal canal of adjacent permanent teeth associated with ectopically erupting canines, and to verify the existence of related factors. The sample consisted of 255 consecutive patients (159 females and 96 males, mean age 18.4 and 16.8 years, respectively). Three hundred and thirty-four ectopic maxillary canines and adjacent teeth were analysed using CT images. Statistical significance was evaluated with chi-square and Fisher's exact tests. The results showed that severe root resorption of adjacent permanent teeth occurred in 17.7 per cent of ectopic canines and was equally common in females and males. Severe root resorption affected 12.6 per cent of the lateral incisors, 4.8 per cent of the first premolars, and 2.1 per cent of the central incisors. No relationship was found between the type or side of ectopic eruption, inclination of the longitudinal axis of the ectopic canine and the occurrence of severe root resorption. A significant relationship was found between a bucco-lingual position of the ectopic canine and root resorption (P < 0.05). Root resorption mainly occurred in the apical third (57.6 per cent) and apical and middle thirds (27.1 per cent). A significant relationship existed between the occurrence of root resorption and complete loss of space for the erupting canine (P < 0.05). No association was found between alignment of the upper permanent incisor and root resorption. A widened dental follicle occurred in 15 per cent of ectopic canines but did not cause root resorption of the adjacent permanent teeth. Since root resorption is asymptomatic, early detection by radiographic examination is essential for correct diagnosis and treatment.     

三段弓技术与微种植支抗技术压低和内收上切牙效果的对比研究

目的：对比两种不同技术-三段弓技术与微螺钉支抗滑动技术,在正畸治疗过程中产生的牙齿以及骨骼的效应差异。方法：对三段弓技术组的18例患者以及微螺钉支抗组的19例患者均进行切牙的内收和压低,分析测量所有患者的头颅定位侧位片以评估两种技术的差异。在水平和垂直方向上对两组患者上颌第一磨牙的移位和相对骨骼改变进行分析。同时在根尖周X光片上对牙根吸收进行测量。结果：U1-SN（P〈0.05）,覆盖、覆、PP-U1、U1水平移动（P〈0.01）,UL-U1（P〈0.05）,在三段弓组和微螺钉支抗组均有明显减小。然而,在三段弓组,U6角度（P〈0.01）,MP-SN、PP-U6（P〈0.05）和U6水平移动（P〈0.05）,与微螺钉组相比均有显著增加。两组的治疗周期及牙根吸收率无显著性差异。结论：采用反Spee曲线弓丝的微螺钉支抗滑动技术,被证明是有效地的内收并压低上颌前牙的口内支抗增强装置。与三段弓技术相比,微螺钉技术在水平（前后向）或垂直方向均未见支抗丧失。