上颌阻生尖牙引起中切牙严重根吸收后自体修复1例

上颌尖牙阻生在正畸临床较为常见,腭侧阻生比例远高于唇侧(3∶1),且与乳尖牙滞留、侧切牙先天缺失或牙根短小、牙量-牙弓长度不调、外伤及特发性因素(包括萌出初期失败)等有关[1-2]。尖牙阻生可导致邻牙牙根内、外吸收等严重后果。本文报道1例上颌阻生尖牙引起同侧中切牙严重根吸收、锥形侧切牙易位迟萌及乳尖牙滞留,经拔     

上颌尖牙-侧切牙唇侧易位的三维影像研究

目的应用锥形束CT(CBCT)研究上颌尖牙-侧切牙唇侧易位的三维特征。方法选取在南京医科大学附属口腔医院正畸科就诊并由CBCT三维影像诊断为上颌尖牙-侧切牙唇侧易位的患者40例,共计涉及46颗尖牙,在三维图像上分析易位尖牙与邻牙的关系、易位的特征,将易位尖牙分成5类。结果唇侧易位上颌尖牙均为冠唇向倾斜,近远中向以近中倾斜(80.4%)为主。在相邻中切牙、侧切牙中,10颗(21.7%)中切牙发生牙根吸收,且均累及根中1/3,8颗(17.4%)侧切牙发生重度牙根吸收。易位尖牙以Ⅲ、Ⅳ类多见,分别占总数的23.9%、39.1%。尖牙长轴越接近水平,尖牙牙尖距离正中矢状面越近,距离牙合平面越远,中切牙的牙根吸收率也越高。结论 CBCT三维定位有助于准确判断易位尖牙的位置以及与邻牙的关系,为制定治疗方案提供指导。     

上颌尖牙埋伏阻生患者上颌切牙牙齿宽度改变的研究

目的探讨中国人上颌切牙宽度与尖牙阻生是否存在内在的联系.方法选择103名上颌尖牙埋伏阻生患者,分为46名腭侧阻生组和57名唇侧阻生组.选择年龄、性别匹配,上颌尖牙正常萌出的患者60名,作为对照组.测量这些患者的上颌切牙近远中宽度,并进行统计学分析.结果尖牙阻生患者的左右侧中切牙及侧切牙的近远中宽度基本一致,无统计学差异.尖牙唇侧阻生患者的侧切牙宽度大于对照组,腭侧阻生患者的侧切牙宽度小于对照组,均有统计学差异.唇腭侧阻生患者的侧切牙宽度有显著性差异.结论尖牙埋伏阻生患者的上颌切牙宽度变化和尖牙阻生的位置有着高度的相关性.     

上颌阻生尖牙牵引治疗后邻近切牙牙根吸收情况的研究

目的 分析上颌阻生尖牙正畸牵引治疗后邻近切牙的牙根吸收情况及可能的相关因素。方法 选取上颌尖牙阻生且符合标准的43例患者,年龄10～23岁,共60颗上颌埋伏阻生尖牙。上颌阻生尖牙正畸牵引治疗前后分别拍摄锥形束CT,分析阻生尖牙邻近切牙的牙根吸收程度,并对可能存在的相关因素进行分析。结果 上颌阻生尖牙正畸牵引治疗后,上颌中切牙发生轻、中、重度牙根吸收的概率分别为71.7%、15.0%、13.3%,上颌侧切牙发生轻、中、重度牙根吸收的概率分别为48.3%、36.7%、15.0%,上颌中切牙与侧切牙牙根吸收严重程度存在差异(P<0.05)。位于腭侧及颌骨内、低位且靠近面中线的阻生尖牙,在正畸牵引治疗后,侧切牙牙根吸收程度较重(P<0.05)。低位阻生尖牙牵引治疗后,中切牙牙根吸收较重(P<0.05)。牵引时间较长时,中切牙牙根吸收程度较重(P<0.05)。治疗前已发生牙根吸收的切牙,在阻生尖牙牵引治疗后发生的牙根吸收程度较重(P<0.05)。结论 上颌侧切牙在阻生尖牙正畸牵引治疗后,发生的牙根吸收程度较重。上颌阻生尖牙正畸牵引治疗后,邻近切牙牙根吸收情况与阻生尖...     

阻生尖牙牵引治疗前后上颌切牙牙根外吸收的锥形束CT分析

目的通过锥形束CT测量探讨阻生尖牙牵引治疗前后上颌切牙牙根外吸收的变化。方法选取2011年7月至2019年1月于南京医科大学附属口腔医院正畸科就诊的上颌尖牙阻生致切牙牙根外吸收的患者24例, 年龄(12.3±1.6)岁(10～14岁), 其中男性11例, 女性14例。将治疗前牙根发生外吸收的上颌切牙纳入吸收组(中切牙21颗, 侧切牙22颗), 以牙根未发生外吸收的同名上颌切牙为对照组(中切牙26颗, 侧切牙21颗)。对正畸治疗全部完成满1年的患者进行随访并拍摄锥形束CT, 随访到患者15例, 其中吸收组中切牙10颗、侧切牙12颗, 对照组中切牙16颗、侧切牙12颗。测量分析上颌切牙在牵引前(治疗前)、牵引后(阻生尖牙牵引到位时)及随访时(正畸治疗全部完成后1年)的牙根长度及牙体体积, 同时分析尖牙牵引期间(牵引前-牵引后)及随访期间(牵引后-随访时)牙根长度及牙体体积的变化量。结果牵引后吸收组和对照组中切牙和侧切牙牙根长度及牙体体积均显著小于同组牵引前(P<0.05)。除吸收组侧切牙牙体体积外, 随访时吸收组和对照组切牙牙根长度及牙体体积均显著小于同组牵引后(P<0.05)...     

上颌尖牙腭侧埋伏阻生的锥形束CT定位诊断

目的应用锥形束CT（CBCT）探讨上颌腭侧埋伏阻生尖牙的埋伏特征及邻牙牙根吸收情况。方法选取南京医科大学附属口腔医院正畸科就诊的上颌尖牙腭侧埋伏阻生的青少年患者22例,获取CBCT三维数据,应用Dolphin imaging 11.0软件,分析腭侧埋伏尖牙的埋伏状况、与邻牙位置关系并分类,观察邻牙牙根的吸收情况。结果上颌腭侧埋伏尖牙大多近中、腭向倾斜阻生,近中异位以Ⅰ类和Ⅳ类较为多见,分别占30.8%和38.5%;近中倾斜角度多在53.8°~68.5°,腭侧异位距正中矢状面多在5.4~8.4 mm。年龄越大,上颌腭侧埋伏尖牙近中腭向异位越远,近中倾斜角度越大。84.6%的相邻侧切牙及19.2%的中切牙牙根与埋伏尖牙接触;50%的相邻侧切牙及15.4%的邻中切牙牙根吸收,相邻侧切牙吸收多位于根尖1/3,而相邻中切牙吸收多位于根中1/3;相邻切牙牙根吸收概率与腭侧埋伏尖牙与切牙间的最小距离呈反比关系。结论CBCT能在三维方向诊断上颌尖牙埋伏状况及与邻近组织的关系,准确判断邻牙根吸收情况,准确测量埋伏尖牙倾斜度及埋伏深度,为上颌腭侧埋伏尖牙的治疗提供指导。     

单侧上颌尖牙阻生对牙颌三维结构的影响

目的: 采用锥形束CT（CBCT）研究单侧尖牙阻生病例牙颌的三维结构特征,评估发生上颌尖牙阻生的相关风险因素,为正畸临床早期干预提供依据。方法: 选取30例单侧上颌尖牙阻生患者的CBCT,利用Romexis软件进行三维重建,测量、比较两侧牙颌三维结构特征指标,采用SPSS17.0软件包进行配对t检验和相关数据的回归分析。结果: 阻生侧尖牙和侧切牙倾斜度明显增大,尖牙牙冠更向近中、侧切牙向远中倾斜（P<0.001）;阻生侧尖牙体积更大、侧切牙体积更小（P<0.05）,当尖牙体积增大或侧切牙体积减小时,上颌尖牙的阻生概率增加;阻生侧牙弓弧形长度更短,牙弓宽度在尖牙区和前磨牙区更短（P<0.001）,而宽度在磨牙区无显著差异（P>0.05）,两侧牙弓长度在尖牙区、前磨牙区和磨牙区无显著差异（P>0.05）。结论: 上颌尖牙阻生伴随或导致同侧牙及牙槽骨三维方向发育异常,上颌尖牙阻生的严重程度与周围牙颌结构异常密切相关,提示上颌尖牙阻生可以早期预判、诊断,且可以实施有效的早期干预。     

上颌侧切牙与尖牙不完全易位的早期矫治

目的：探讨上颌侧切牙与尖牙不完全易位的早期矫治方法。方法：替牙期上颌侧切牙与尖牙不完全易位病例8例,采用＂2×4＂矫治技术,切开翻瓣术,辅弓牵引尖牙、侧切牙复位。结果：8例上颌侧切牙与尖牙不完全易位者经过8～12个月的治疗,易位的上颌尖牙与侧切牙排列到正常位置。结论：上颌尖牙与侧切牙不完全易位,应早期矫治,以避免上颌侧切牙牙根吸收及完全易位的发生,矫治中的关键是减少尖牙与侧切牙间的移动阻力。     

曲面断层片和锥形束CT对上颌阻生尖牙的定位分析

目的:通过对曲面断层片中上颌阻生尖牙近远中向和垂直向的影像学分区,判定其与锥形束CT (cone-beam computed tomography, CBCT)中相应尖牙唇腭侧位及相邻恒切牙根吸收之间的关系。方法:对68例患者的94颗上颌阻生尖牙进行曲面断层片的拍摄和CBCT扫描。将曲面断层片中上颌阻生尖牙近远中向牙尖所处的位置分为5区(Ⅰ区-Ⅴ区),将牙冠所处的垂直向高度分为3部分(牙冠段,根中段,根尖段),其唇腭侧位置和相邻恒切牙的根吸收情况则由CBCT判定。结果:曲面断层片中上颌阻生尖牙近远中向的区域定位与CBCT中相应阻生牙的唇腭侧位之间有显著相关(P＜0.001),唇侧阻生的尖牙常出现在曲面断层片中的Ⅰ、Ⅱ、Ⅲ区域,正中牙槽阻生的多在Ⅳ区域,腭侧阻生的常在Ⅴ区域,而垂直向的分段与之无显著相关。CBCT中相邻恒切牙的根吸收常发生在Ⅳ、Ⅴ区域和根中段、根尖段。曲面断层片中阻生尖牙近远中向和垂直向的区域划分均与CBCT中相邻恒切牙的根吸收之间有统计学意义(P＜0.05)结论:利用曲面断层片中上颌阻生尖牙近远中向的区域定位可以预测其唇腭侧位和相邻恒切牙的根吸收,垂直向的分段可用来判断相邻恒切牙的根吸收,而不可推测其唇腭侧阻生情况。     

上颌腭侧埋伏阻生尖牙 CBCT 导引下的牵引治疗

目的:探讨锥形束CT(CBCT)三维(3D)重建在上颌腭侧埋伏阻生尖牙牵引治疗中的指导作用。方法:对22例上颌尖牙(共26颗)腭侧埋伏阻生的青少年患者行CBCT检查。CBCT三维重建观察尖牙形态、腭侧埋伏状况,测量分析与邻近组织的位置关系及相邻切牙牙根吸收情况。结果:CBCT能够真实再现颌骨内埋伏的上颌尖牙。埋伏尖牙均近中倾斜,与平面平均成角61.1°±18.1°,近中异位分别为Ⅰ类埋伏尖牙8颗、Ⅱ类5颗、Ⅲ类3颗、Ⅳ类10颗。3颗相邻侧切牙及2颗中切牙因严重牙根吸收而拔除;26颗上颌腭侧埋伏尖牙均成功牵引至平面排入牙弓并建立正常咬合。结论:CBCT能立体再现上颌尖牙腭侧埋伏阻生特征及与邻近牙的关系等,对治疗方案的制定、开窗牵引具有指导作用,可提高疗效。     

Maxillary incisor impaction and its relationship to canine displacement.

This study aimed to examine the eruption status of unerupted maxillary permanent canines in patients who also had an impacted central incisor. Seventy-five unilateral cases of the incisor anomaly were retrospectively examined. Using the initial panoramic films, we assessed the positions of the ipsilateral and contralateral canines and the lateral incisors and the timing (eruption progress) of the canines. The final position of the canines was evaluated from patient records and progress photographs. The data showed a significant increase in prevalence and severity of displaced canines in the ipsilateral side (41.3%) compared with the contralateral side (4.7%). Palatally displaced canines occurred in 9.5%, buccally displaced canines in 30.2%, and canine-lateral incisor transposition in 1.6% of the patients. Half of the buccally displaced canines in the ipsilateral side were pseudotransposed with the adjacent lateral incisor. The eruption timing of ipsilateral undisplaced canines was either similar or delayed, relative to the contralateral tooth, but never accelerated. The ipsilateral lateral incisor was strongly angulated because of a more distally located apex (5 mm) rather than a mesially tipped crown. The ipsilateral canine was relatively more superiorly positioned (undererupted). Patients who had trauma had a significantly higher prevalence and severity of canine displacement and more distally displaced lateral incisor apices. Initial height of incisor impaction did not influence the results. These data provide evidence of a significant environmental influence of an impacted maxillary central incisor in delaying and altering the eruption path of the ipsilateral maxillary canine.     

The impacted maxillary canine. Further observations on aetiology, radiographic localization, prevention/interception of impaction, and when to suspect impaction

A bstract — Adjacent anomalous or missing maxillary lateral incisors have been implicated in the aetiology of palatally displaced canines by not providing proper guidance to the canine during its eruption. However, a recent review of the literature suggests that the aetiology of palatally displaced canines is genetic in origin. The aetiology of labially impacted canines differs, being due to inadequate arch space. Vertex occlusal radiographs have been recommended for localization but have limitations, and a case is illustrated where this radiograph is deceptive. The prevention/interception of a palatally displaced canine by the extraction of the deciduous canine is best carried out as early as the displacement is detected, mostly soon after 10 years of age. Usually, prevention/interception will avoid the surgical and orthodontic treatment needed to align a palatally impacted canine and may help prevent resorption of the adjacent incisor root. Suspicions that an impaction could occur or has occurred arise a) before the age of 10 years if there is a familial history and/or the maxillary lateral incisors are anomalous or missing; b) after the age of 10 years if there is asymmetry in palpation or a pronounced difference in eruption of canines between the left and right side; or, the canines cannot be palpated and occlusal development is advanced; or, the lateral incisor is proclined and tipped distally; and, on a panoramic radiograph of the late mixed dentition if the incisal tip of the canine overlaps the root of the lateral incisor.     

上颌埋伏并与侧切牙易位的尖牙的正畸矫治

目的：探讨上颌埋伏并与侧切牙易位的尖牙的正畸矫治。方法：采用带钩的改良Nance弓联合直丝矫治技术治疗了2例替牙期上颌埋伏并和侧切牙易位尖牙病例,首先用改良Nance弓的末端钩在高位水平地牵引尖牙冠向颊侧及后方移动,同时用直丝弓技术使侧切牙排齐、根近中移动、牙体整体腭侧移动,使尖牙冠和侧切牙根在冠状向分开。然后采用“随形弓”,在维持两者在冠状向和垂直向的距离情况下,不断改变“随形弓”置于尖牙托槽上弓丝水平臂的第二序列弯曲,使两个交叉的易位牙体不断换位。结果：2例患者尖牙及侧切牙恢复正常的排列顺序,牙髓、牙周健康,治疗时间27个月。结论：矫治上颌埋伏并与侧切牙易位的尖牙关键是创造足够的空间,使两个易位牙的牙体换位时无干扰。改良Nance弓联合直丝矫治技术是一种有效的方法。     

Treatment of a transmigrated and an impacted mandibular canine along with missing maxillary central incisor: A case report

IntroductionTreatment of a case with impacted canines is complex and numerous options are available ranging from disimpaction to forced eruption.ObjectiveThe objective of this case report was to describe the treatment of a 19-year-old male, with a skeletal Class II, dental Class II Division 1 malocclusion, prognathic maxilla, proclined maxillary incisors, with missing left maxillary central incisor and bilateral mandibular canine impaction.MethodologyThe orthodontic treatment plan included forced eruption of the impacted canines and conversion of maxillary left lateral incisor to central incisor.ConclusionProper diagnosis and implementation of orthodontic biomechanics can minimize the amount of prosthetic and surgical intervention needed in the management of transmigrated canine and smile designing.     

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??Objective    To evaluate the position of maxillary impacted canines and resorption of neighboring incisors with cone beam computed tomography ??CBCT??. Methods    Impacted maxillary canines in sixty-seven patients were selected and scanned by the Planmeca ProMax 3D at Stomatological Hospital of Jilin University from Dec.2015 to Jan.2017. The three-dimensional images were obtained by Invivo 5.4.5 software. Each impacted canine was positioned and the root resorption of adjacent incisors was observed in sagittal??coronal and axial views. Results    In sagittal plane view??except 10 horizontal impacted canines ??12.0%?? and 1 inverted impacted canine ??1.2%????33.7% of impactions were labial??30.1% were palatal??and 22.9% were middle. In coronal plane view??12.0% of the cusp tips of maxillary impacted canines were near the crown of the adjacent incisor??42.2% were near cervical third of the root of the adjacent incisor??24.1% were near middle third of the root of the adjacent incisor??9.6% were near apical third of the root of the adjacent incisor??and 12.0% were near the root tip of the adjacent incisor.In axial plane view??65.1% of impactions were mesial??12.0% of impactions were distal??and 9.6% were middle. About 17.9% lateral incisors had root resorption??and 9.7% central incisors ??13?? had root resorption??the difference being statistical ??P < 0.05??. Conclusion    CBCT is a better way in the diagnosis and analysis of the position and root resorption of maxillary impacted canines??which provides guidance to the treatment.     

上颌埋伏阻生中切牙的影像学分类

目的:探讨上颌埋伏阻生中切牙的三维图像分类特征。方法:根据103例上颌中切牙埋伏阻生患者螺旋CT的Dicom原始数据,应用Mimics10.0软件重建出上颌埋伏阻生中切牙的三维图像,分析上颌埋伏阻生中切牙的阻生特点,并对其进行分类。结果:共有埋伏牙106颗。74颗牙为唇侧阻生,倒置阻生33颗,水平阻生28颗,倾斜阻生13颗;20颗为腭侧阻生,倾斜阻生11颗,水平阻生9颗;12颗为垂直阻生。上颌埋伏阻生中切牙根据牙冠的位置在垂直向、冠状向、矢状向可分为3类,即①唇侧埋伏阻生型,包括唇侧倾斜埋伏阻生型、唇侧前后水平埋伏阻生型、唇侧倒置埋伏阻生型;②腭侧埋伏阻生型,包括腭侧倾斜埋伏阻生型、腭侧后前水平埋伏阻生型;③垂直埋伏阻生型。结论:上颌埋伏阻生中切牙从三维方向上可分为3类,每一类又可分多个亚型,包括唇侧(倾斜、前后水平、倒置)埋伏阻生、腭侧(倾斜、后前水平)埋伏阻生和垂直埋伏阻生。     

Prediction of maxillary canine impaction using eruption pathway and angular measurement on panoramic radiographs

ObjectivesTo compare the normal eruption pattern and angulation in impacted maxillary canines using panoramic radiographs to predict maxillary canine impaction.Materials and MethodsPatients aged 6 to 15 years were classified into the normal eruption group (n = 229) and the impaction group (n = 191). At least two panoramic radiographs were taken in the normal eruption group during the eruption process of the maxillary canine. The growth pattern of the maxillary canine was analyzed using an XY coordinate system, with the tip of the maxillary lateral incisor as the origin and the tooth''s long axis as the Y-axis and measurement of the relative position of the crown tip and angulation of the maxillary canine.ResultsThe crown tips of normally erupted maxillary canines were intensively distributed along the distal surface of the maxillary lateral incisor, while those of impacted canines were widely distributed. The angulations of the normally erupted canines increased as eruption increased along the lateral incisor and then decreased at the cervical point of the lateral incisor. The angulations of the impacted canines were scattered, with no uniform pattern.ConclusionsWhile using the normal eruption path of the maxillary canine and the pattern of change in angulation based on the distal surface of the maxillary lateral incisor, early intervention or regular follow-up is needed to prevent maxillary canine impaction.