上颌第三磨牙牙冠最大周径、牙尖与牙根相互关系的探讨

目的 通过上颌第三磨牙牙冠最大周径与牙尖型推断牙根型。方法 观察100颗离体上颌第三磨牙的牙冠最大周径、牙尖型和牙根型,列表总结并作统计学处理。结果1.上颌第三磨牙的牙冠最大周径均值为32.21mm,牙尖以三尖型占多数（48％）,牙根以融合根型或单根型占多数（52％）;2 影响上颌第三磨牙牙根型的主要因素是牙冠最大周径,而不是牙尖型;牙尖型与牙根型的关系属间接联系。结论 建议临床通过上颌第三磨牙的牙冠最大周径并同时参考牙尖型推断牙根型。     

上颌第三磨牙牙尖与牙根的关系的探讨

本文对４２０颗上颌第三磨牙Ｈｅ面牙尖与牙根关系进行了探讨。结果表明：Ｈｅ面牙尖呈四型，依次为三尖型（５２．３８％），四尖型（３４．５３％），双尖型（９．５２％）和五尖型（３．５７％）。牙根呈三型，依次为融合根（４８．５７％），双根３２．８６％）和三根（１８．８６％）。Ｈｅ面牙尖为二尖型和三类型的上颌第三磨牙，其牙根多为融合根，占６８％，而多根占３２％（其中双根为２５％，三根为７％）；Ｈｅ面牙尖为四     

汉族下颌第三磨牙牙尖与牙根的关系

本文对342颗下颌第三磨牙(牙合)面牙尖与牙根的关系以及阻生的临床类型与牙根数目之间的关系进行了探讨。结果表明:(牙合)面牙尖呈四型,分别是四尖型、五尖型、六尖型和八尖型。牙根呈三型,分别是融合根型、双根型和三根型。(牙合)面牙尖为四尖型,其融合根比例高达71.01％,五尖型融合根比例降为27.97％,双根比例升为61.91％。六尖型没有融合根,双根约占3/4(74.19％),三根约占1/4(25.81％)。八尖型都是三根。 阻生类型中水平位和颊向位融合根的比例大,分别为85.714％和56.43％。近中位、舌向位和垂直位则双根的比例高,分别为60.417％、58.334％和47.619％。以垂直位和远中位三根比例最高,分别为25.397％和25.0％,其余各类型中三根的比例均不足9％。     

上颌第三磨牙根管形态的显微研究

目的研究上颌第三磨牙根管的解剖形态并寻找牙根与根管之间的对应关系。方法从150颗患者被拔除的上颌第三磨牙中,筛选牙体较完整的融合根30颗和分叉根17颗,利用显微cT扫描后行三维重建,观察其根管全貌,并对根管类型进行统计分析。结果17颗分叉根的根管形态全部为3管型或4管型,其中15颗根管数目与牙根数目一致;30颗融合根则出现了多种根管形态,其根管数目为1～4个不等。结论上颌第三磨牙根管形态变异大,但分叉根的根管形态相对简单,而融合根的根管形态反而复杂,牙根和根管数目往往不一致。     

上颌第三磨牙根管形态的CBCT研究

目的：应用锥形束CT（cone?beam computed tomography ,CBCT）技术研究上颌第三磨牙的根管形态,为临床治疗提供解剖学依据。方法随机调取397颗上颌第三磨牙的CBCT资料,分析上颌第三磨牙的牙根数目、根管数目、根管分类等。结果397颗上颌第三磨牙中,三根牙最多,占43.07%;融合根牙次之,占40.30%。分析根管数目显示,三根管最多,占47.86%;单根管次之,占28.21%。根据Vertucci根管分类,89.6%的牙根以Ⅰ型根管为主,但仍会出现根管治疗时较难操作的Ⅱ型、Ⅲ型、Ⅴ型、其他型等根管。结论上颌第三磨牙根管解剖形态多样,根管系统复杂、变异大。     

下颌第三靡牙牙尖、阻生类型与牙根的相关关系

目的：本文对1090颗下颌阻生第三磨牙H面牙尖、阻生类型与牙根的相互关系进行了探讨。结果：He面牙尖呈六型，分别是三尖型（0．55％）、四尖型（26．42％）、五尖型（53．58％）、六尖型（18．16％）、七尖型（0．83％）和八尖型（0．46％）。牙根呈四型，分别是融合根型（35．14％）、双根型（57．34％）、三根型（7．34％）和四根型（0．18％）。He面牙尖数目少，融合根比例高，三尖主要是融合根型；牙尖根数目增加，双根和三根比例上升。七尖型、八尖型没有融合根型。阻生尖型以近中位最多见（31．62％），垂直位（29．085），颊向位（16．88％），远中位、舌向位和水平位均不足9％，远中位融合根比例高达47．06％；近中位、垂直位水平位双根比例高，分别为64．35％、58．04％和57．73％；颊向位垂直位三根比例高，分别达13．04％和11．35％，其余各类型中三根的比例均不足9．5％，结论：各阻生类型均符合He面牙尖数少数少融合根比例高，He面牙尖数多，双根和三根的比例高的规律。     

下颌第三磨牙的解剖形态观察

目的：探讨下颌第三磨牙的解剖外形及其根管口的形态特点,为牙体牙髓病的临床治疗提供理论依据.方法：收集临床拔除的下颌第三磨牙159颗,观察牙尖和牙根数目,测量牙体长度、牙冠最大近远中径和最大颊舌径;拍摄颊舌向和近远中向X线初始片;开髓、拔髓、疏通根管,体视显微镜测量各根管口之间的距离.结果：外形上,下颌第三磨牙根长大于冠长,近远中径大于颊舌径.单根居多,占54.09%,其次是两根,占40.51%.下颌第三磨牙的根管数目1～4,以两根管（55.35%）居多.S型根管14例,C型根管36例（22.80%）,其中Ⅰ型50.0%,Ⅱ型36.1%,Ⅲ型13.9%.多根管牙的各根管口之间的距离最小0.35 mm,最大5.00mm;均值2.13～3.95.结论：下颌第三磨牙根管系统较为复杂,可以出现C型、S型及弯曲根管.     

青海地区人群下颌第三磨牙的形态研究

目的:研究青海地区人群下颌第三磨牙形态特征,为临床诊疗提供科学依据.方法:收集122个青海地区人群下颌第三磨牙,测量牙齿的全长、冠长、根长、近中远中径、颊舌径、牙尖数目和牙根数目等并进行统计学分析.结果:青海地区人群中下颌第三磨牙全长、冠长及颊舌径男女之间有统计学差异(P＜0.05),牙尖型和牙根型存在正相关关系.结论...     

新疆地区人群上颌第二磨牙牙根和根管形态的CBCT研究

目的 采用锥形束CT研究新疆地区人群上颌第二磨牙的牙根和根管形态，为本地区口腔临床诊疗提供参考依据。方法 对纳入研究的539例新疆地区人群的上颌第二磨牙，利用CBCT对其牙根形态、数目，根管形态、数目和弯曲度，牙冠颊舌径和近远中径以及对称性进行观察、分析和统计。结果 在1017颗上颌第二磨牙中，三根牙的检出率最高为85.2%，四根牙检出率最低为3.2%，不同牙位和性别在牙根形态上的分布存在统计学差异；MB2的检出率与年龄无统计学差异；56岁及以上年龄组的四根牙检出率最高。颊舌径、近远中径的平均测量值越大，其对应的根管数目越多。上颌第二磨牙的牙根数目和形态对称、根管形态及四种特征均对称方面较高，上颌第二磨牙近颊根管和远颊根管68%为重度弯曲，弯曲位于根中1/3较多。结论 新疆地区人群上颌第二磨牙以三根牙为主，对称率较高，弯曲程度大，但存在一些牙根和根管的变异，临床上可以运用CBCT来指导诊疗。     

上颌前磨牙牙根及根管系统及其与上颌窦关系的锥形束CT研究

目的:采用锥形束CT (CBCT)方法研究上颌前磨牙牙根及根管系统及其与上颌窦之间的关系,以期为临床应用提供数据性参考。方法:收集866例上颌前磨牙的CBCT影像学资料(上颌第一、二前磨牙各1732颗),按照性别分组,应用NNTviewer软件观察牙根长度、牙根及根管数目、根管构型、上颌前磨牙牙根与上颌窦的关系及与性别变化的关系。结果:上颌前磨牙以单根最为多见,单根牙具有更多样的根管构型,大多数双根上颌前磨牙表现为Ⅳ型构型(96.3%),Ⅷ型根管仅在三根上颌前磨牙中出现。16.5%的上颌前磨牙牙根与上颌窦相贴或突入其中。结论:上颌前磨牙根管系统复杂多样,单根牙根管变异发生最多,牙根与上颌窦垂直关系密切。     

上颌第三磨牙根形态与根管形态的研究

目的：寻找上颌第三磨牙根形态及根管形态的规律。方法：使用传统的牙透明技术,充分显露该牙髓腔外形,在体式显微镜下读取根管系统的形态,并统计分类。结果：103颗上颌第三磨牙,融合根占72%,分叉根占28%;完全融合型牙根单根管（1-1型）多见,不完全融合牙根中双根管（2-2）和三根管（3-2;3-3）为主;分叉根型中近中颊根分为双管型常见;根尖分歧和根管侧枝在各型根管中均可见到。结论：上颌第三磨牙融合根常见,但根管形态多样。     

上颌第一、第二恒磨牙牙根和根管系统的锥形束CT研究

目的：运用锥形束CT（CBCT）观察中国人群双侧上颌第一、第二磨牙的牙根和根管系统的解剖形态,为临床根管治疗提供依据。方法：选择200名患者的双侧上颌第一、第二恒磨牙（上颌第一恒磨牙354颗、上颌第二恒磨牙360颗）的CBCT扫描数据,使用NNT软件分析上颌第一、第二恒磨牙的牙根数、根管数、根管分型以及双侧对称情况。结果：上颌第一、第二磨牙主要为三根（99.44%和84.44%）。上颌第二磨牙的单根和双根较多见（15.28%）,其根管系统形态复杂,在根尖区有融合趋势。上颌第一磨牙的根管系统主要为3根四根管（78.97%）。上颌第二磨牙的三根管和四根管发现率接近（分别为47.37%和51.64%）。上颌第一磨牙的近颊根管系统主要根管分型为：Ⅳ型（57.79%）、Ⅱ型（19.83%）和Ⅰ型（15.58%）。上颌第二磨牙的近颊根管系统主要根管分型为：Ⅰ型（48.14%）、Ⅳ型（30.43%）和Ⅱ型（17.39%）。上颌第一、第二磨牙的远颊根和腭根主要为单根单根管,存在少量和罕见的变异。上颌第一、第二磨牙近颊根的根管数目和根管分型左右对称。结论：上颌第一磨牙近颊根管系统变异普遍存在,MB2根管为其主要的变异形式。上颌第二磨牙牙根数目和根管形态变异类型多,单根牙和双根牙的根管走向复杂多变。CBCT可以为识别根管形态提供准确依据。     

Root and canal morphology of Thai maxillary molars

AIM: To investigate the root and canal morphology of 268 maxillary permanent molars collected from an indigenous Thai population. METHODOLOGY: The cleaned teeth were accessed, the pulp dissolved by sodium hypochlorite under ultrasonication, and the pulp system injected with Indian ink. The teeth were rendered clear by demineralization and immersion in methyl salicylate. The following observations were made: (i) number of roots and their morphology; (ii) number of root canals per root; (iii) root-canal configuration in each root using Vertucci's classification with additional modifications; and (iv) presence and location of lateral canals and intercanal communications. RESULTS: All the maxillary first and second molars had three separate roots. Only, half (51%) of the maxillary third molars had three separate roots; the other half had fused or conical roots. The majority of the distobuccal (98.1-100%) and palatal (100%) roots had type I canals. Over half of the mesiobuccal roots of first (65%) and second (55%) molars had two canals. The most common (44.2%) canal configuration in mesiobuccal roots of first molars was type IV (two canals, two foramina). A variety of canal types were found in the mesiobuccal roots of second molars. Maxillary third molars showed the greatest diversity of canal morphology. There was an increase in the prevalence of lateral canals towards the apical part of the roots and intercanal communications were present in 16% of each of first, second and third Thai maxillary molars. CONCLUSIONS: The mesiobuccal roots of Thai maxillary molars possessed a variety of canal system types. Over 50% of the first molars had a second mesiobuccal canal. The palatal and distobuccal canals mainly had type I canals. Only, a small proportion (7.3-13.3%) of the roots exhibited lateral canals which were the most common in the apical third     

Root canal morphology of human maxillary and mandibular third molars

The anatomy of third molars has been described as unpredictable. However restorative, prosthetic, and orthodontic considerations often require endodontic treatment of third molars in order for them to be retained as functional components of the dental arch. The purpose of this study was to investigate and characterize the anatomy of maxillary and mandibular third molars. One hundred fifty maxillary and 150 mandibular extracted third molars were vacuum-injected with dye, decalcified, and made transparent. The anatomy of the root canal system was then recorded. Seventeen percent of mandibular molars had one root (40% of which contained two canals), 77% had two roots, 5% had three roots, and 1% had four roots. Teeth with two roots exhibited highly variable canal morphology, containing from one to six canals, including 2.2% that were "C-shaped." Fifteen percent of maxillary molars had one root, 32% had two roots, 45% had three roots, and 7% had four roots. Teeth with one root demonstrated the most unusual morphology, with the number of canals varying from one to six. An in vivo study of the canal morphology of treated third molars is suggested to provide the practitioner with an understanding of the clinical implications of third molar root anatomy.     

Root and canal morphology of Burmese maxillary molars

AIM: To investigate the root and canal morphology of Burmese maxillary molars using a canal staining and tooth clearing technique. METHODOLOGY: Maxillary molars (239) were collected from indigenous Burmese patients and designated; first (90), second (77), third (72) molars. Following pulp tissue removal and canal system staining with Indian ink, the teeth were decalcified with 10% nitric acid, dehydrated and cleared with methyl salicylate. The following features were evaluated: (i) number of roots and morphology; (ii) number of canals per root: (iii) root canal configuration (Vertucci's classification); (iv) number of apical foramina per root; (v) number and location of lateral canals; and (vi) the presence of intercanal communications. RESULTS: All first and second molars had three separate roots, whilst third molars had one of five different root forms, of which three separate (25%) or fused (31%) roots were most prevalent. The majority of palatal (100%) and disto-buccal (96%) roots possessed one canal (type I). The prevalence of mesio-buccal roots with two canals decreased from first to third molars (68%, 49%, 39%, respectively); type II (two orifices, one apical foramen) and IV (two orifices, two apical foramina) configurations were the most common. Single/fused rooted third molars had a range of number and type of canals. Most roots in all molars had one apical foramen, those with four apical foramina were confined to third molars. Intercanal communications were most prevalent in mesio-buccal roots and two/three fused rooted third molars. Lateral canals were most prevalent in the apical third of the roots of all molars. CONCLUSIONS: The mesio-buccal roots of Burmese maxillary molars possessed a variety of canal system types. Over 50% of the first and second molars had a second mesio-buccal canal, of which over 20% had intercanal communications. The palatal and disto-buccal canals mainly had type I canals. Lateral canals were equally prevalent in all tooth types but were most common in the apical third.     

Evaluation of root canal morphology of human primary molars by using CBCT and comprehensive review of the literature

Objective Knowledge of primary tooth morphology is essential for clinical dentistry, especially for root canal treatment and dental traumatology. However, this has not been well documented to date with a large sample. This study was carried out to investigate the variation in number and morphology of the root canals of the primary molars, to study the applicability of cone beam computerized tomography (CBCT) in assessing the same and to provide a comprehensive review of the literature. Materials and methods A total of 343 primary molars, without any root resorption, were divided into four main groups including the maxillary first molars, maxillary second molars, mandibular first molars and mandibular second molars. All of them were analysed in CBCT images in the axial, sagittal and coronal planes. Various parameters such as the number of roots, number of canals, the root canal type, diameter of root and root canal and root canal curvature were studied. Results Primary molars in all four groups showed variability in the number of roots and root canals. As far as length of the roots was concerned, the palatal root of the maxillary molar was found to be longest, while the distobuccal root was shortest. In mandibular molars, the mesial root was longer than the distal root. The length of distobuccal root canal of the maxillary molars and the distolingual canal of the mandibular molars was found to be shortest. The number of roots and root canals varied from two to four and three to four, respectively. The maxillary molars exhibited more one-canal than two-canal roots. Conclusion The present study provides comprehensive information to the existing literature concerning the variation in root canal morphology of the maxillary and mandibular primary molar teeth. These data may help clinicians in the root canal treatment of these teeth.     

Evaluation of Root Canal Configuration of Maxillary Molars in a Brazilian Population Using Cone-beam Computed Tomographic Imaging: An In Vivo Study

Introduction

The aim of this study was to analyze and characterize root canal morphology of maxillary molars of the Brazilian population using cone-beam computed tomographic (CBCT) imaging.

Methods

Patients referred for a CBCT radiographic examination for accurate diagnosis and treatment planning were enrolled in the study. A total of 620 healthy, untreated, fully developed maxillary first and second molars were included (314 first molars and 306 second molars). The following observations were recorded: (1) number of roots and their morphology, (2) number of canals per root, (3) fused roots, and (4) primary variations in the morphology of the root canal systems.

Results

First and second molars showed a higher prevalence of 3 separate roots, mesiobuccal, distobuccal, and palatal, with 1 canal in each root (52.87% and 45.09%, respectively). Two canals in the mesiobuccal roots represented 42.63% of teeth, whereas mesiobuccal roots of second molars presented 2 canals in 34.32%. The most common anatomic variation in the maxillary first molar was related to the root canal configuration of the mesiobuccal root, whereas the root canal system of the maxillary second molar teeth showed more anatomic variables.

Conclusions

Mesiobuccal roots of maxillary molar teeth had more variation in their canal system than the distobuccal or palatal roots. The root canal configuration of the maxillary second molars was more variable than the first molars in a Brazilian population. CBCT imaging is a clinically useful tool for endodontic diagnosis and treatment planning.