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.     

上中切牙短根畸形患者骨性错[牙合]和轴倾度的临床分析

目的探讨昆明市人群中非综合征型短根畸形(short root anomaly,SRA)的患病率及与骨性错[牙合]和上中切牙轴倾度分布的关系,为SRA患者的正畸临床诊疗提供一定参考。方法回顾性分析2011年1月~2019年7月笔者所在医院收治患者CBCT数据库并随机抽样选取1000例,诊断出SRA患者27例(SRA组);对照组,为非SRA患者中随机选取的100例患者,根据其临床资料以及头影测量数据,将骨性错[牙合]分为I类骨性错,Ⅱ类骨性错[牙合],Ⅲ类骨性错[牙合]3个亚组,将中切牙轴倾度分为唇倾型、腭倾型和正常唇倾度型3个亚组,分析SRA组和对照组的性别、骨性错[牙合]以及上中切牙轴倾度分布情况。结果本研究所选人群中SRA的患病率为2.7%,女性的SRA患病率为3.67%(21/572),高于男性患病率1.4%(6/428),SRA患病率的性别差异具有统计学意义(χ^2=4.562,P=0.033)。SRA患者与对照组骨性错[牙合]构成比差异具有统计学意义(χ^2=8.710,P=0.013)。SRA患者骨性错以Ⅲ类骨性错[牙合]为主。SRA患者与对照组上中切牙轴倾度型构成比不同,差异具有统计学意义(χ^2=16.75,P<0.001)。SRA患者上中切牙轴倾度以腭倾型为主。结论SRA与Ⅲ类骨性错[牙合]及前牙腭倾型轴倾度有关,正畸治疗前需对此类患者的冠根比和根形进行评估。     

两种方法矫治不同年龄组安氏Ⅱ^2错[牙合]畸形的临床研究

目的研究两种不同矫治方法唇倾、压低青少年及成人安氏Ⅱ类2分类错[牙合]畸形的上中切牙的临床疗效。方法选择安氏Ⅱ类2分类的患者41例,根据年龄分为青少年组(A)和成人组(B),每组患者随机分为两组,分别用种植钉、摇椅弓唇倾压低上中切牙。治疗前后拍摄CBCT,测量分析治疗前后上中切牙的位置及牙槽骨的改变。结果治疗完成时41例患者均达到正常覆[牙合]、覆盖,上中切牙均有唇倾,差异具有统计学意义,P<0.05;阻抗中心点种植钉组压低,差异有统计学意义,P<0.05;牙槽缘点压低,差异有统计学意义,P<0.05;唇侧根尖水平牙槽骨厚度(b3)增加,腭侧根中、根尖水平牙槽骨厚度(p2,p3)减少,差异有统计学意义,P<0.05,治疗前后相关测量项目在青少年与成人之间没有显著差异。结论种植体支抗可以有效地矫治安氏Ⅱ类2分类舌倾的上中切牙,并且可以真性压低上中切牙,青少年与成人之间矫治前后上中切牙变化没有明显差异。     

乳切牙外伤与恒中切牙发育畸形埋伏阻生的关系

恒牙埋伏阻生是口腔正畸临床常见的错畸形 ,其中以上下尖牙和上切牙为常见。据报道尖牙埋伏阻生发生率为 0 .92 - 3.3%不等 ,恒切牙埋伏阻生的发生率未见报道 ,Ｗｉｌｌｉａｍ等认为较尖牙发生率为少 ,而房伯君等报道恒切牙埋伏阻生多于尖牙。恒牙埋伏阻生的原因至今还不十分明确 ,上中切牙埋伏阻生的原因之一是乳切牙早期外伤乳牙根伤及恒牙胚所致 ,本文报告三例上中切牙埋伏阻生发育畸形的临床病例 ,并从其诊断及处理进行分析讨论。病例一周某 ,男 ,10岁 ,替牙主诉 :2 1|未萌 ,要求矫治现病史 :患者四岁时因摔跤而致乳切牙外伤临床检…     

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目的    评价上中切牙正畸治疗后根吸收状况，探讨影响根吸收的相关因素。方法    从大连大学附属口腔医院正畸科2名资深医生2007年5月至2009年12月所完成的正畸病例中，随机选择233例（男85例，女148例）。分为成人组90例，平均年龄（21.73 ± 3.68）岁；青少年组143例，平均年龄（13.37 ± 1.81）岁。通过分析治疗前后的头颅侧位片观察上中切牙牙根形态与长度变化，评价上中切牙根吸收状况。结果    233例患者中的13例上中切牙发生了不同程度的根吸收，根吸收发生率为5.58%。成人女性拔牙矫治组的上中切牙根吸收程度高于青少年女性拔牙矫治组，差异有统计学意义（P < 0.05）。青少年组中，女性拔牙矫治患者的根吸收程度较男性拔牙矫治患者明显，差异有统计学意义（P < 0.05）。而是否拔牙，其上中切牙根吸收程度差异无统计学意义（P > 0.05）。结论    女性拔牙矫治患者治疗后的上中切牙根吸收发生率较高。正畸根吸收原因复杂，治疗前应详细分析各种根吸收易发因素，以减小正畸根吸收的发生和程度，维持正畸牙齿的健康。     

上颌中切牙双根双根管1例报道

患者 ,女 ,70岁。右上中切牙为孤立牙 ,牙冠形态正常 ,近中牙颈部深龋 ,因修复需要局麻下拔除 ,发现为唇舌向分根牙 ,根分叉位于根尖 1/ 3处 ,经舌面开髓后插入光滑髓针 ,摄X线牙片显示为双根管 (见图 1)。上中切牙有双根与双根管畸形的可能 ,由于为唇舌向分根并重叠 ,常规X线片很难发现 ,临床上对于上颌中切牙根管治疗后出现疼痛或慢性瘘管等表现时 ,在排除其他原因的情况下 ,应考虑是否有分根畸形而遗漏根管未作治疗的可能。　　图 1　上中切牙双根双根管畸形上颌中切牙双根双根管1例报道@郭家平$广州军区武汉总医院口腔科!湖北武汉43007…     

上颌切牙腭窝根面沟畸形与牙周病、牙髓病的关系

<正> 上颌切牙腭窝根面沟畸形为畸形腭侧窝的一种特殊类型(又称切牙根发育畸形或根面舌沟畸形、腭龈沟畸形)。其特征为腭窝深陷且形成一纵形沟裂,越过舌隆突延伸至根面。文献中早有关于上颌切牙腭窝根面沟畸形的报道。Frank.G.于1972年对625只上颌侧切牙进行检查,发现有该种畸形的18只占2.88%。本文检查了686只因各种原因被拔除的上颌切牙(侧切牙183只,中切牙493只)其中5只侧切牙(2.73%),2只中切牙(0.41%)有该类畸     

氢氧化钙制剂诱导根尖形成的探讨

临床上儿童前牙因外伤冠折、双尖牙畸形中央尖 ,引起一系列病变 ,影响了牙根发育。近二年来 ,我们采用控制感染及药物诱导的方法进行治疗 ,获得了满意效果。　　作者单位 :330 0 0 6南昌 ,江西医学院第二附属医院口腔科　　一、材料和方法患儿共 18例 ,年龄 8～ 14岁 ;男性 10例 ,女性 8例。上中切牙 11颗 ,侧切牙 3颗 ,下双尖牙 4颗 ,上中切牙、侧切牙为外伤性冠折牙。牙本质折断未露髓患牙 9颗。露髓患牙5颗 ,双尖牙均为畸形中央尖折断后牙髓感染。牙髓急性炎症者 6例 ,牙髓慢性炎症者 12例 ,这些患牙均无根尖病变。彻底清理根管 ,去尽感…     

上中切牙牙冠矢状向正畸安全移动范围函数研究

目的 利用影像学资料拟合上中切牙牙冠矢状向正畸安全移动范围函数。方法 以眶耳平面（FH平面）为x轴,垂直于FH平面为y轴,治疗前上中切牙切缘点为原点建立坐标系。根据上中切牙平移和旋转2种形式在坐标轴中描绘其正畸移动轨迹,以根颈1/3外侧缘触及骨皮质为平移界限,以根颈1/3为中心进行旋转的∠U1-FH（上中切牙长轴与眶耳平面相交的下内角）在105.5～116.5°范围内为旋转界限,构建上中切牙牙冠矢状向正畸安全移动范围函数,并采用Matlab设计函数表达。选取2020年9月至2021年9月就诊于山西医科大学第五临床医学院口腔正畸科的成人患者30例,通过函数计算上中切牙安全移动距离,再结合Downs分析法确定目标移动量。分析患者治疗后上中切牙的实际移动量及倾斜度变化,以及是否发生牙根吸收、骨开窗及骨开裂等并发症。结果 根据治疗前的∠U1-FH,分别拟合了105.5°<∠U1-FH <116.5°、∠U1-FH≥116.5°和∠U1-FH≤105.5°3种条件下的内收运动函数和外展运动函数,通过治疗前∠U1-FH、上中切牙1/3根长与冠长之和、颊侧和腭侧牙槽骨厚度的测量可计算得出...     

儿童上颌中切牙间隙的病因分析及矫治

上颌中切牙间隙是儿童较为常见的错畸形。作者通过对北京儿童医院正畸门诊收治的118例上中切牙间隙病例的临床分析,发现其发生原因是复杂多样的,本文旨在通过对上中切牙间隙病因的分析,提出矫治时机和矫治方法的选择,为临床医生对上颌中切牙间隙的认识、诊断、治疗提供参考。     

唇腭裂患者上颌前部牙槽骨厚度及骨开窗、骨开裂的三维评价研究

目的　利用锥形束CT（cone-beam CT,CBCT）评价不同类型唇腭裂患者上颌前部牙槽骨厚度和形态,以及上前牙骨开窗、骨开裂情况。方法　选择016年8月至019年10月间在南京医科大学附属口腔医院就诊拟行口腔正畸治疗的唇腭裂患者85例（男51例,女34例,平均年龄（14.65±4.95）岁）,其中单侧唇裂伴牙槽突裂（unilateral cleft lip and alveolus,UCLA）患者19例,单侧完全性唇腭裂（unilateral complete cleft lip and palate,UCLP）患者5例,双侧完全性唇腭裂（bilateral complete cleft lip and palate,BCLP）患者14例。在正畸治疗开始前均予以拍摄颌面部CBCT,应用Image J软件测量其上前牙唇腭侧牙槽骨厚度（alveolar bone thickness,ABT）,计算骨开窗、骨开裂发生率,并比较不同唇腭裂类型患者上颌前部ABT及上前牙骨开窗、骨开裂发生率的差异。结果　UCLP、UCLA患侧上前牙骨开裂发生率（34.9%、4.9%）显著高于其健侧（10.7%、11.1%）,但骨开窗发生率无统计学差异。UCLP健侧上中切牙（5.9%）、侧切牙（9.7%）骨开裂发生率低于UCLA。UCLA、UCLP、BCLP三组间患侧上前牙骨开裂及骨开窗发生率均无统计学差异。UCLP、UCLA患侧上前牙ABT在多部位小于其健侧。除UCLP/UCLA患侧侧切牙外,UCLA、UCLP、BCLP各类型上前牙唇侧平均ABT均小于腭侧。UCLA、UCLP、BCLP三组间患侧上前牙唇腭侧平均ABT无统计学差异。UCLP患侧上侧切牙、尖牙分别在唇侧和腭侧根颈处ABT大于UCLA。结论　单侧唇腭裂患者患侧上前牙骨开裂发生率高于健侧,ABT则在多部位小于其健侧;而三种类型患者上前牙唇侧ABT均小于其腭侧。单侧唇裂伴牙槽突裂与单侧完全性唇腭裂患者健侧上中切牙、侧切牙骨开裂发生率及患侧侧切牙、尖牙根颈处牙槽骨厚度存在差异;单侧与双侧完全性唇腭裂间上前牙骨开窗、骨开裂发生率及牙槽骨厚度则无差异。     

A survey of approximal root concavities in an ethnic Chinese population

Eight hundred and forty teeth were surveyed, 60 approximal surfaces for each tooth type being studied. Approximal root concavities were completely absent in maxillary central incisors, in contrast with mandibular central incisors of which 73% had concavities on mesial surfaces and 93% on distal surfaces. Similarly, a markedly higher prevalence was found for mandibular lateral incisors and canines. However, mandibular first and second molars had fewer approximal concavities than their maxillary counterparts. In maxillary teeth, concavities were more frequent on distal surfaces, while for mandibular teeth no definite pattern was seen. In both maxillary and mandibular teeth, approximal concavities often started in enamel, extending down to the root surface. There were differences in the approximal root topography of Chinese teeth in comparison with other populations.     

Stress distribution pattern in a root of maxillary central incisor having various root morphologies

Abstract Objective: To investigate stress distribution in the roots of maxillary central incisors bearing various types of root morphologies with regard to application of different types of orthodontic forces using the finite element model (FEM). Materials and Methods: FEMs of maxillary central incisors with different root morphologies (normal, short, blunt, dilacerated, and pipette) were constructed, and orthodontic forces in various directions (intrusion, extrusion, tipping, and rotational) were applied to the tooth axis at the bracket level. Result: On application of various forces, significantly increased stress was seen at the apex of the root with dilacerated morphology and at the cervical one-third region of the tooth with the short root. Increased stress was observed at the middle one-third region in the tooth with the pipette-shaped root during intrusion and extrusion. Conclusions: In the present study, the stress distribution pattern indicates that the maxillary central incisors with deviated root morphology are at higher risk of root resorption.     

In vitro study of the incidence of radicular grooves in maxillary incisors.

The purpose of this investigation was to determine the prevalence of radicular grooves in 500 central and 421 lateral extracted maxillary incisors. Radicular grooves were present in 2.0% of the central and 2.6% of the lateral maxillary incisors. The majority of radicular grooves in central maxillary incisors were detected on the buccal root surface (1.6%), and fewer on the lingual root surface (0.4%). In lateral maxillary incisors, the radicular grooves were always observed on the lingual surface.     

Stress distribution pattern in a root of maxillary central incisor having various root morphologies: A finite element study

Objective:To investigate stress distribution in the roots of maxillary central incisors bearing various types of root morphologies with regard to application of different types of orthodontic forces using the finite element model (FEM).Materials and Methods:FEMs of maxillary central incisors with different root morphologies (normal, short, blunt, dilacerated, and pipette) were constructed, and orthodontic forces in various directions (intrusion, extrusion, tipping, and rotational) were applied to the tooth axis at the bracket level.Result:On application of various forces, significantly increased stress was seen at the apex of the root with dilacerated morphology and at the cervical one-third region of the tooth with the short root. Increased stress was observed at the middle one-third region in the tooth with the pipette-shaped root during intrusion and extrusion.Conclusions:In the present study, the stress distribution pattern indicates that the maxillary central incisors with deviated root morphology are at higher risk of root resorption.     

微种植体支抗辅助内收上切牙后牙槽骨改建的锥形束CT研究

目的:探索运用微种植体支抗结合高位牵引钩大量内收上颌切牙后牙槽骨的改建情况。方法:以22例青少年上颌前突拔牙矫治患者,上颌切牙内收前、内收完成后的锥形束CT（cone-beam CT,CBCT）为研究样本,应用Mimics 15.0行CBCT影像三维重建,明确上颌切牙移动方式,利用Invivo5.0三维定点测量唇、腭侧牙槽骨厚度和高度变化。采用SPSS19.0 软件包对测量数据进行配对t 检验。结果:上颌切牙切缘与根尖均发生水平舌侧移动,但切缘的移动距离大于根尖;切缘点发生向下移动,根尖点出现明显的向上移动。上切牙腭侧牙槽骨厚度及唇腭侧总厚度在根颈1/3和根中1/3均显著减小（P<0.05）,而根尖1/3显著增加（P<0.05）,腭侧牙槽骨高度显著降低（P<0.05）。结论:青少年上颌前突患者微种植体支抗结合高位牵引钩可以实现受控制的倾斜移动。大量内收上颌切牙后,其腭侧牙槽骨吸收远大于唇侧增生,牙槽骨并没有完全跟随牙的移动而改建,提示正畸矫治时不宜过度内收前牙。     

三种矫治器治疗安氏Ⅱ类2分类对切牙牙根吸收的影响

目的 比较不同矫治器治疗安氏Ⅱ类2分类错牙合畸形患者切牙牙根的吸收状况。方法 选择使用不同矫治器的安氏Ⅱ类2分类成年患者30例,其中传统MBT托槽、自锁托槽以及无托槽隐形矫治器的患者各10例,共计240颗切牙。收集患者治疗前后的锥形束CT(CBCT)影像学资料,并导入Dolphin Imaging软件,Mimics软件以及3-Matics软件测量分析治疗前后切牙牙根吸收情况。结果 传统MBT托槽组和自锁托槽组的上下颌中切牙以及侧切牙的牙齿长度(L)与无托槽隐形矫治器组上下颌中切牙及上颌侧切牙的牙齿长度治疗后较治疗前显著减小,差异具有统计学意义。使用无托槽隐形矫治器的患者下颌侧切牙治疗前后的牙齿长度无显著变化。而三组之间的对比,上下颌中切牙牙齿长度变化无显著统计学差异。无托槽隐形矫治器组上下颌侧切牙的牙齿长度减少量相对更低,差异具有统计学意义(P＜0.05)。此外,无托槽隐形矫治器组平均牙齿长度变化为(-0.37±0.11)mm,显著小于传统MBT托槽组(-1.32±0.47)mm及自锁托槽组(-1.05±0.38)mm。在牙根吸收区域的比较上,各组均表现为腭侧吸收多于唇侧吸收,近中吸收多于远中吸收。结论 无托槽隐形矫治器治疗安氏Ⅱ类2分类错牙合畸形可有效降低切牙牙根吸收严重程度。     

Growth hormone receptor gene is related to root length and tooth length in human teeth

Objectives:To examine the relationship between tooth length and growth hormone receptor (GHR) gene variants in a healthy Japanese population.Materials and Methods:The subjects consisted of 193 Japanese adults (69 men, 124 women), aged 13 to 56 years. Genomic DNA was extracted from saliva and genotyped GHR rs6184 and rs6180 variants using the Taqman genotyping. Computed tomography (CT) images were acquired using a dental cone-beam CT scanner and reconstructed using open-source OsiriX medical image processing software. The maxillary (upper; U) and mandibular (lower, L) central incisors (1), lateral incisors (2), canines (3), first premolars (4), second premolars (5), first molars (6), and second premolars (7) were evaluated. Teeth were assessed for crown height (CH), root length (RL), overall tooth length (C+R), and crown to root ratio (C/R). The relationships between GHR variants and CH, RL, C+R, and C/R were statistically examined.Results:The GHR variant rs6184 was associated with the root lengths and tooth length for the upper and lower lateral incisors and upper canines (U2 RL; U3 RL, C+R; L2 RL [P < .05]).Conclusions:The results indicate that the GHR rs6184 variant is associated with tooth length and ratio dimensions in a Japanese cohort. Further studies utilizing a larger sample size are needed to confirm this finding.     

Intraoral distribution of Actinobacillus actinomycetemcomitans in young adults with minimal periodontal disease

The aim of the present study was to investigate the intraoral distribution of Actinobacillus actinomycetemcomitans in young adults with minor signs of periodontal disease but harboring the organisms in the oral cavity. 17 healthy volunteers, 20 to 27 years of age, participated. Samples from mucosal surfaces of the oro-pharyngeal cavity and saliva (n = 221) as well as subgingival plaque from every tooth (n =477) were selectively cultivated for A. actinomycetemcomitans. Species identity and presence of the leukotoxin encoding gene, ltxA, were checked by multiplex polymerase chain reaction. Moreover, the leukotoxin promoter region was analyzed. No isolate harbored a 530 bp deletion in the promoter region of the leukotoxin gene, signaling minimally toxic strains. 42.1 +/- 30.4% extracrevicular and 34.4 +/- 29.5% subgingival samples were culture-positive. In extracrevicular samples, the organism could easily be recovered from cheek mucosa (62%), saliva (59%) and the palatal tonsils (41%). Mean log-transformed numbers of A. actinomycetecomitans colony forming units (CFU/ml) in culture-positive material ranged between 1.8 from the hard palate and 2.3 from 10 microl saliva. The highest prevalence in subgingival plaque was observed at maxillary 3rd molars (55%) followed by maxillary lateral incisors (50%) and mandibular 3rd molars (41%). Mean log-transformed counts of CFU/ml ranged between 2.2 at maxillary 3rd molars and 3.4 at upper central incisors. When adjusted for jaw, site and tooth type, the odds of isolating higher numbers of the organism were increased with every mm probing depth by a factor of 1.35 (p <0.05). The odds ratio for bleeding on probing was 1.38. Thus, in this young adult population with minor periodontal disease, A. actinomyetemcomitans was mainly associated with some deviation from gingival health. Of concern might be a minority of subjects (29%) with an extremely wide distribution of the organism in the oral cavity.