下颌恒磨牙根管系统形态学比较

目的 了解根管的形态结构。为牙疾病治疗提供解剖学参考。方法 采用透明标本法对460颗下颌磨牙的根管系统进行研究。结果 （1）下颌第1磨牙三根出现率为15.5%，下颌第2、3磨牙融合根的出现率分别为20.5%和63.3%。（2）在下颌磨牙分离根的根管类型中，第1磨牙近中很多为Ⅳ类根管，第2磨牙近中根多为Ⅲ类根管，第3磨牙近中根多为Ⅰ类根管，而下颌磨牙远中根绝大多数为Ⅰ类根管。（3）在融合根中，均出现一定数量的C形根管和多口，多孔类根管。结论 下颌磨牙牙根变异多，融合牙根比分离根有更复杂的根管系统。     

下颌第二磨牙"C"形融合根及其根管形态的观察

目的　观察具有“C”形融合根的离体下颌第二磨牙牙根外形及根管形态。方法　通过牙根水平片切及透明标本的制作 ,观察 4 0颗下颌第二磨牙牙根的形态特点 ,并测量其长度。结果　牙根均在颊侧融合 ,牙根长度较正常牙长且有显著性差异 (P <0 .0 5 )。根管形态变异较多 ,仅 4 0 %呈现根颈到根尖的“C”形 ,3 0 %为“分号”形 ,10 %为“分离”形 ,2 0 %的牙根内各横断面形态可有不同。结论　下颌第二磨牙“C”形融合根的变异较多 ,不利于根管的彻底清理和充填     

下颌第一恒磨牙牙根及根管系统文献回顾(附病理报告)

目的：研究下颌第一恒磨牙牙根及根管系统。方法：报告1例双侧下颌第一恒磨牙近中3根管病例,分析其诊疗经过并复习牙根及根管系统文献。结果：该病例中双侧下领第一恒磨牙根管治疗后进行完善根管充填。结论：下颌第一恒磨牙的牙根及根管系统变异多样,临床治疗中应注意,以提高根管治疗的成功率。     

下颌第二磨牙牙根及根管形态学研究

目的：观察下颌第二磨牙牙根及根管类型。方法：收集临床上拔除的下颌第二磨牙86颗,通过透明牙方法,观察牙根的分类、根管的分型和侧副根管的发生情况。结果：86颗下颌第二磨牙中,有44颗双根牙,36颗融合牙,6颗三根牙。双根牙中,近中根管以2－2型居多,其次为1－1型,远中根管大部分为1－1型根管。36个融合牙中,C型根10个,2例近远中完全融合形成2－1型根管,剩余近远中有独立2根管,24例中近远中根管以1－1型常见。无论牙根形态如何,近中根管均有广泛的根管交通;结论：下颌第二磨牙牙根和根管形态具有多样性,给临床根管治疗带来困难。     

下颌第二磨牙根管的解剖形态研究

目的 了解下颌第二磨牙根管的解剖形态，为根管治疗提供依据。方法 用透明标本法将152个下颌第二磨牙依次作髓腔染色，5％盐酸脱矿，酒精系列脱水，最后置冬青油制成透明牙观察根管形态。结果 下颌第二磨牙双根85例（55．9％），其近中根1－1型根管40例（47．1％），2－1型23例（27．1％），1－2型13例（15．3％），2－2型9例（10．6％）；远中根根管1－1型79例（92．9％）。C形根56例（36．8％），其中仅有24例C形根管（15．8％），完全性C形根管及部分性C形根管各12例。结论 根管形态的多变性及C形根管的存在给下颌第二磨牙的根管治疗带来困难，彻底的根管清理，严密的根管充填是治疗成功的关键。     

下颌第一恒磨牙根管弯曲度的研究

目的：确定下颌第一恒磨牙的根管弯曲程度的情况。方法；收集36个离体的下颌第一恒磨牙，在根管中分别插入15－^#25的根管扩大针，拍摄近远中向（临床）和颊舌向（邻面）的X线片，用Photoshop5.0软件分析根管的弯曲率，根管的构型采用Vertucci分类法。结果：大多数的近中根管在2个观察方向均显示有不同程度的弯曲，弯曲发生处多为根中1／3，近远中向的近中颊要管弯曲度最高（P＜0．05），颊舌向的近中颊，舌根管可在根尖1／3显示第二个弯曲度，弯曲程度均高于同一根管的第一个弯曲度，VertucciⅡ型占近中根的64％。大多数的远中根管无明显的弯曲，且多是单根单根管。结论：下颌第一恒磨牙的近中根管多有不同程度的弯曲，了解根管的弯曲对于成功的牙髓，尖周病治疗是必要的。     

下颌第二磨牙C形根管的研究进展

下颌第二磨牙根管变异中特殊的C形根管，其复杂的根管形态给根管的彻底清理和封闭充填带来较大的困难。这一现象使很多学者将更多的目光投注到对下颌第二磨牙根管系统的结构，尤其是C形根管形态结构的研究上。作者通过回顾近年来对下颌第二磨牙C形根管的大量系统研究，主要阐述了其基本特征、根管变异趋势以及近期的研究进展。     

双侧下颌第一恒磨牙融合根伴C形根管1例

下颌第一恒磨牙的牙根通常为2~3根伴2~4个根管,融合根伴C形根管较罕见。本文报道1例双侧均为融合根伴C型根管的下颌第一恒磨牙患者。     

下颌第二磨牙根管系统的临床诊断和治疗

目的:探讨下颌第二磨牙根管系统的特征及临床诊断和治疗方法。方法:选取患牙髓炎或根尖周炎的下颌第二磨牙 127个,拍摄术前X线片,探查根管,确定根管形态和类型;采用机用镍钛器械Hero642预备根管,热牙胶垂直加压技术充填根管。根据治疗前后的X线片评价根管预备和充填效果。结果:下颌第二磨牙独立 3个根管的发生率为 54. 3%, 独立 2个根管和单一根管的发生率为 11. 0%和 3. 1%,C形根管的发生率为 31. 5%,以Ⅰ、Ⅱ型居多。所有患牙均无根管内并发症发生,治疗效果佳。结论:下颌第二磨牙根管系统以独立的 3个根管为主,其次为C形根管,根管探查结合X线片可诊断C形根管;机用镍钛器械预备根管热牙胶垂直加压技术充填根管可获得良好的治疗效果。     

老年人群下颌第一磨牙根管结构和近中根根面形态研究

目的:使用CBCT观察老年人下颌第一磨牙根管和牙根牙面形态.方法:纳入98名老年患者的98颗下颌第一磨牙CBCT影像,观察根管结构及近中根根面凹陷情况.结果:老年人下颌第一磨牙的近中根根管结构以Ⅳ型为主,占比78.6％;远中根以Ⅰ、Ⅱ型为主,占比分别为44.9％和12.2％;所有的近中根远中面都存在凹陷,56％近远中面...     

Root form and canal anatomy of mandibular first molars in a southern Chinese population

Abstract Racial differences in dental crown morphology have long been recognised, but the diverse aspects of root form and canal anatomy of human teeth have not received the same attention. The majority of books on dental anatomy fail to supply detailed information of the features of root and root canal morphology that occur at particularly high frequency in Mongoloid populations. These features have not been systematically documented and the implications that these variations may have upon clinical endodontics have not been fully reported. In this study 100 mandibular first molars extracted from Hong Kong Chinese patients were examined visually and radiographically. For each tooth, the number of roots, root canals, and apical foramina were noted. Fifteen per cent of the mandibular first molars examined were found to be 3-rooted. Forty-five per cent of the sample displayed 2 distal canals and 28% of the teeth had 2 separate distal apical foramina. The frequency of the second distal canal is higher than the previously reported findings for non-Mongoloid groups.     

Localization of root canal orifices in mandibular second molars in relation to occlusal dimension

Aim  To evaluate the localization and distribution of canal orifices of mandibular second molar teeth in relation to the mesio-distal and bucco-lingual dimensions of coronal tissue.
Methodology  Fifty extracted mandibular second molar teeth were embedded into plaster blocks with their vertical axes aligned perpendicular to the horizontal plane. The teeth were photographed digitally from the occlusal aspect under 12 × magnification. Thereafter, the occlusal halves of crowns were sectioned off to expose the root canal orifices. The teeth were than photographed under the same magnification, after which the pre- and post-sectioning images of each specimen were stacked into a single file. To plot the coordinate of each canal orifice, a 0.5-mm grid analytical plane was mounted digitally on the stack so that the x - and y -axes of the plane were superimposed on the mesiodistal and buccolingual axes (bisectors) of the tooth crowns. Localization and distribution of the coordinates of the canal orifices were evaluated using the chi-square test ( P  = 0.05).
Results  Only one tooth displayed a single root canal orifice, located in the mesiobuccal-distolingual 'centre' of the occlusal surface. The majority of mandibular second molars had three orifices (72%), followed by those with two (16%) and four (10%). The distal canal was located lingual to the centre of the occlusal plane.
Conclusion  The distal canal was located lingual to the centre of the occlusal plane of mandibular second molars. The possibility of observing more divergent localizations and orifice numbers should not be overlooked in clinical practice.     

山东地区人群下颌第二磨牙C形根管系统的发生率

目的研究山东地区人群下颌第二磨牙C形根管系统的发生率。方法应用流行病学调查的方法,选取年满18周岁,自出生以来一直在山东境内居住者的下颌第二磨牙为研究对象,拍摄X线片,根据C形根管系统的X线特征判断其发生率。结果纳入本研究的共有879名调查者、1752颗下颌第二磨牙。其中,具有C形根管系统的有471颗,发生率为26.88%。结论C形根管系统在山东地区人群下颌第二磨牙中具有较高的发生率,对其解剖形态进行研究具有重要的临床意义。     

Root canal anatomy of mandibular first premolars in a southern Chinese population

Abstract Racial differences in dental crown morphology have long been recognized, but the frequency of genetically determined variations in the root canal anatomy of teeth has not been fully established. There is, therefore, a need to study the morphology of non-Caucasoid teeth to establish the existence and prevalence of racially determined root canal variations. In this study 100 mandibular first premolars of Chinese origin were accurately identified and radiographed in vitro to establish the frequency of root canal bifurcation. Thirty-six per cent of the sample presented with more than one canal. The division of these canals occurred at various levels of the root, and in all but one of the teeth the canals remained separate.     

Root and canal morphology of Burmese mandibular molars

AIM: To study the root canal morphology of Burmese mandibular molars using a canal staining and tooth clearing technique. METHODOLOGY: Mandibular molars (331) were collected from indigenous Burmese patients and designated; first (139), second (134), third (58) molars. Following pulp tissue removal and staining of the canal systems with Indian ink, the teeth were decalcified and rendered clear with methyl salicylate. Under magnification (x3), the following features were evaluated: (i) root number 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: Most of the mandibular molars had two separate roots (90% in first molars, 58% in second molars, 53% in third molars) and three-rooted teeth were (10%) confined to first molars. C-shaped roots occurred in 22.4% of mandibular second molars and a further 14.9% had two fused roots. The majority (81-100%) of conical distal roots possessed a simple type I (single canal) configuration. Whilst the canal system of mesial roots was more complex: 52-85% contained two canals, of which type II (two orifices, one foramen) and type IV (two separate canals) were the most prevalent. A broad range of 6.5-70% had intercanal communications. Fused/single-rooted molars had a wide variety of canal system types but intercanal communications were rare except in C-shaped roots (33%) of second molars. The majority of roots of all molars contained one or two apical foramina (91-96%) and the apical third had the highest prevalence of lateral canals. CONCLUSIONS: There was a high prevalence of three-rooted mandibular first molars and C-shaped roots/canals in mandibular second molars from a Burmese population. Conical roots tend to have simple canal systems, whilst flatter/broader roots have more complex canal systems.     

Root complex and root canal system: a correlation analysis using one-rooted mandibular second molars

Abstract – The principal aim of this investigation was to verify an expected, probable correlation between certain variables, which are initially represented in the macrostructure of the root complex corresponding to the cemento-dentin junction, and certain variables that subsequently manifest themselves in the root canal system. A material consisting of 76 one-rooted, permanent mandibular second molars (M2 inf) was used. The specimens were cut at the mid-root level and all observations were made on the coronal root segment using a stereomicroscope. Relevant variables of the root complex were observed. The total macromorphologic variation of the root complex could be subdivided and classified in well-defined, distinguishable types. In accordance with the single root complex type an expected, logically deduced configuration of the root canal system was established. The relevant variables of the canal system were then recorded. Finally, the root complex morphology, as well as the expected and actually observed canal configuration, were compared type by type. In 76.3% of the teeth a good concordance could be shown between the expected and the actual canal configuration, whereas in 23.7% of the specimens there was a divergence. In 42.1% of the investigated teeth, 1 centrally localized main canal with varying cross section images, among them a C-shaped image, was found. In 30.3%, 2 main canals were found, which were often localized mesially and distally. In 23.7%, 3 main canals were observed: 1 mesiofacial, 1 mesiolingual and 1 distal. In the remaining 3.9%, 1 non-independent supernumerary canal was seen in a distolingual position.     

下颌第二磨牙根管显微镜下根管口分型探讨

目的通过显微镜分析下颌第二磨牙根管口的解剖特点及分型。方法选择患牙髓炎或根尖周炎的下颌第二磨牙653个,根管显微镜下观察并记录根管口形态,对其根管口形态分类计数,计算其出现率。结果下颌第二磨牙单根牙Ⅰ-1型47例(7.20%),Ⅰ-2型65例(9.95%),Ⅰ-3型263例(40.27%),Ⅰ-4型22例(3.37%);C形根管256例(39.21%)。完全C形根管及部分C形根管分别占17.31%、21.90%。结论根管显微镜下可以更好地观察下颌第二磨牙根管口形态,提高C形根管诊断率。根管口形态呈C形根管系统较多,不利于根管的彻底清理和充填。     

大量根充糊剂进入下颌管10年观察1例报告

根管治疗是通过机械和化学方法取出根管内的大部分感染物,并通过充填根管、封闭冠部,防止发生根尖周病变或促进已经发生的根尖周病变的愈合[1]。下颌后牙周围解剖结构接近下颌管,在根管治疗过程中,机械性、化学性或热刺激都有损伤下牙槽神经的潜在风险。如根管充填糊剂超出根尖孔,与神经组织接触,有病例报道会产生细胞毒性及机械挤压造成神经敏感性改变[2]。本文报道1例左下第二磨牙行根管治疗,大量根充糊剂进入下颌管10年观察,患者未出现下牙槽神经损伤症状的病例。