上颌第一恒磨牙髓室底及根尖孔的观察

目的 研究上颌第一恒磨牙的髓室底形态,根管口的形态,根管口及根尖孔的数目和位置分布。方法 106颗离体上颌第一恒磨牙,暴露其髓室底,并用苏木素将根尖区染色,用肉眼观察法结合用光滑髓针、15号根管扩大器等探查以明确根管口数,根尖孔数及其位置分布。结果 上颌第一恒磨牙的髓室类似一个底在颊侧的三角形,38.68%为三根管口,61.32%为四根管口,左右分布无差异,四根管口者含一个远中颊侧根管口,一个腭侧根管口,近中颊侧根管又分偏颊、偏腭侧两根管口;远中颊、腭根的根尖均为单孔,近中颊根的双根尖孔率为51.8%,61.54%的根尖孔为侧方开口。结论 上颌第一恒磨牙的开髓洞形应为偏向近中的圆三角形,近中颊根的双根管检出率较高。     

上颌磨牙近颊根根管类型及其临床意义

目的：运用透明标本法观察离体上颌第一、二磨牙近颊根根管形态，并进行分类和讨论其临床意义。方法：收集离体上颌第一、二磨牙共275颗，制成透明标本。根管显微镜下观察、记录近颊根的根管数目、走向、融合和分支情况，并进行分类。结果：①上颌磨牙近颊根管形态各异，可概括为八种类型，双根管中以2-1型和2-2型多见；双根管率在第一磨牙和第二磨牙分别为81．48％和49．7％。②近颊根主根管(MB)和近颊根第二根管(MB2)的尖1/3多弯向远中，MB2在近根管口1mm-3mm处有一斜向近中的弯曲点。结论：掌握上颌磨牙近颊根1-2型、2-1-2型和1-2-1型根管形态，是提高上颌磨牙根管治疗技巧和成功率的关键；有效去除根管近中壁部分突起的牙本质，以减小冠1/3处的弯曲度，可望提高MB2根管的探通率。     

中国人群上颌磨牙近中颊根根管形态研究

目的：研究中国人群中上颌磨牙近中颊根根管的解剖形态。方法：选取138颗离体上颌磨牙，截去牙冠，完全暴露髓室底，用08＃号K锉疏通近中颊根MB及MB2至根尖孔，并扩大至15＃号，对单根管但存在两个根尖孔的牙齿，从根尖孔方向用08＃号K锉逆行通畅根管，术前术后分别用数字X线机从近远中方向和颊腭向行诊断丝平行投照。结果：在138颗离体牙中除了2颗因根管钙化近中颊根MB不能完全用08＃号K锉疏通，其余136颗离体牙中近中颊根Ⅰ型根管有47颗（34.6％）、Ⅱ型根管有46颗（33.8％）、Ⅲ型根管有28颗（20.6％）、Ⅳ型根管有9颗（5.8％）、Ⅴ型根管有6颗（4.4％）。结论：中国人群中上颌第一、第二磨牙近中颊根双根管发生率为65.4％。提示上颌磨牙近中颊根MB2发生率很高，因此掌握其解剖形态对临床完善治疗有着重要的意义。     

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。     

再论磨牙髓腔解剖研究及临床意义

目的：恒磨牙髓腔解剖的再研究。方法：通过开髓、根管预备，测量扩大针进入根管角度和根管长度，冠颈横断观察。结果：髓室底形态有４型；根管口分布类型：上颌磨牙有２类５型，下颌磨牙有３类４型；扩大针进入根管角度及根管长度因根而异。结论：成功地进行牙髓、尖周病的治疗，熟悉髓腔解剖十分重要。     

成人上颌第一磨牙根长、根管数目及形状研究

目的：通过对离体上颌第一磨牙测量根长，观察牙根不同部位根管数目和形状，为临床治疗提供参考资料。方法：收集20岁以上人上颌第一恒磨牙，测量根长度后将牙根横切分为3部分：根上1／3、根中1／3和根尖1／3，在体视镜下观察不同部位的根管数目、形状。结果：上颌第一磨牙腭根、近颊根和远颊根长度分别是（13、82±1．51）mm、（13、06±1、12）mm和（11．64±0．85）mm。近颊根管上1／3双根管检出率为51．00％，根中1／3和根尖1／3分别为53．88％、54、09％；远颊根中1／3和根尖1／3偶见双根管。腭侧根管横截面以圆形为主，未见有双根或多根管存在；近颊根和远颊根管形状变异大，形状多样。结论：上颌第一磨牙腭根和远颊根长度相近，腭根比近颊根长约2—3mm；近颊根和远颊根管形状变异大，近颊根双根管约50％以上，偶见多根管。根管上1／3线条形时，根中1／3和根尖1／3多为双根管。     

上颌第二磨牙根管数目的临床研究

目的观察临床治疗中上颌第二磨牙根管数目。方法临床需要根管治疗的上颌第二磨牙166颗,拍X线片,术中配合使用根管显微镜、超声根管锉、小号K锉及17％EDTA溶液,探查并扩通根管,确定根管数目。用镍钛锉进行根管预备,侧方加压技术充填根管。结果166颗上颌第二磨牙中：单根管牙为2颗（1．2％）;双根管牙（颊根根管、腭根根管）5颗（3．0％）;3根管牙（近中颊根根管、远中颊根根管、腭根根管）为117颗（70．5％）;四根管牙为42颗（25．3％）,其中近中颊根第2根管（MB2）发生率23．5％。结论上颌第二磨牙根管变异较大,临床治疗中应多加注意。     

离体上颌磨牙髓室底形态的比较研究

目的通过对上海地区成年男女上颌第一磨牙和第二磨牙髓室底形态的观察及根管口距离的测量．用相对直观的方法确定根管口的基本位置。并对所测上颌第一磨牙和第二磨牙的数据进行统计学分析和比较，为临床医生在根管治疗时提供更为丰富的解剖学资料。旨在提高临床根管治疗的成功率。方法取上海地区成年人离体牙：上颌第一磨牙38颗。上颌第二磨牙39颗，以釉牙骨质界为基准横截牙颈部且完整暴露根管口在放大镜下观察其髓室底的形态并测量根管口间的距离。结果“Y”形髓室底沟：上颌第一磨牙占50．00％，上颌第二磨牙占58．97％；“7”型分别为：36．84％和25．64％；根管口的间距：腭根管口至近中颊根管口和远中颊根管口的距离上颌第一磨牙为4．92和3．96，上颌第二磨牙为3．53和2．92；近远中根管口的距离分别为2．01和1．68。结论临床可沿髓室底沟根据腭侧根管口和颊侧根管口的间距寻找上颌磨牙的根管．进行有效的根管治疗。     

上颌磨牙近中颊根的寻找和扩通

目的：寻找并尽量扩通上颌磨牙近中颊根第二根管，统计其发生率及通畅率。方法：离体上颌磨牙11颗，开髓、拔髓，寻找并尽量扩通近中颊根第二根管即MB2，根管预备、充填，拍片。统计其发生及发现率。临床上对146颗上颌磨牙开髓、拔髓，寻找并尽量扩通近中颊根第二根管即MB2，根管预备，充填，拍片。结果：离体牙10颗，上颌第一磨牙近中颊根第二根管发现率为60％，通畅率为50％。94颗上颌第一磨牙，近中颊根第二根管发现率为44.68％.通畅率为29.78％，52颗上颌第二磨牙，发现率为11.53％，通畅率为7.69％。结论：上颌第一磨牙近中颊根第二根管的发生率较高，其寻找、定位及扩通尽管有一定的困难，临床医生仍应注意寻找，以提高上颌磨牙根管治疗的成功率。     

上颌第一磨牙近中颊根MB2根管研究

目的：观测上颌第一磨牙近中颊根MB2的存在率,根管口的位置及形态。方法：采用牙体硬组织切片机对拔除的上颌第一磨牙进行连续横断切片,并在显微镜下观测其近中颊根第二根管存在情况,根管口位置及根管形态。结果：220个上颌第一磨牙中有81个存在近中颊根第二根管,存在率为36．81％,近颊根第二根管口横切面形态为圆形或卵圆形,近颊第二根管口与近颊第一根管口,远颊根管口和腭根管口的位置关系呈斜四边形。结论：上颌第一磨牙近中颊根第二根管存在率较高,其开髓形状应为斜四边形。     

锥形束CT结合手术显微镜在上颌磨牙颊侧根管口下方分叉患牙治疗中的应用

目的 探讨锥形束CT检查结合显微根管技术治疗上颌磨牙颊侧根管口下方分叉病例的临床效果.方法 选取需进行根管治疗的上颌磨牙304颗(上颌第一磨牙159颗,上颌第二磨牙145颗),开髓后记录髓室底根管口数目及位置,对术前X线片怀疑为颊侧根管口下方分叉的患牙,先在肉眼下探杳疏通根管,再根据牙科锥形束CT结果 在根管显微镜下在...     

The root and root canal anatomy of maxillary molars in a Chinese population

Abstract The purpose of this investigation was to study the prevalence of fused roots, C-shaped roots, C-shaped root canal orifices and C-shaped root canals in the maxillary molars of a Chinese population. A total of 305 first molars and 309 second molars were collected in Taiwan. The teeth were demineralized and placed in methyl salicylate to make them transparent. Root fusion was examined and the pulp chamber floor was checked for C-shaped orifices. Chinese ink was then injected into the root canal system to demonstrate possible C-shaped canals. The maxillary first molars had the palatal root fused with the mesiobuccal root in 0.3% of the cases, and with the distobuccal root in 2.0%. Teeth with C-shaped roots existed in only 0.3% of maxillary first molars, while 6.2% of the maxillary first molars and 40.1% of the maxillary second molars had fused roots. The maxillary second molars had the palatal root fused with the mesiobuccal root in 18.1% and with the distobuccal root in 2.6%; the palatal root was fused with the mesiobuccal and distobuccal root in 8.1% of the material. The maxillary second molars had a C-shaped root in 4.5% and C-shaped root canal orifices with C-shaped root canals in 4.9% of the cases. Fused roots or incompletely separated roots are common in the maxillary second molars amongst Chinese people, while C-shaped roots and root canals in maxillary molars are not frequently seen.     

上颌第二乳磨牙根管数目的临床研究

目的 观察临床治疗中上颌第二乳磨牙根管数目.方法 选取需行上颌第二乳磨牙根管治疗的3~8岁患儿204例,共216颗患牙.常规方法开髓、制备开髓洞型,使髓室底完全暴露,用小号锉结合17%乙二胺四乙酸(ethylene diamine tetraacetic acid,EDTA)溶液探查各根管口的位置,确定并记录根管数目,根管预备完成后采用碘仿氧化锌糊剂进行根管充填.结果 216颗上颌第二乳磨牙中,122颗为3根管(占56.5%);94颗为4根管(占43.5%),根管数目变异以近中颊根第二根管(second mesiobuccal canal,MB2)出现频率较高,占比41.2%.上颌第二乳磨牙MB2的发现率在性别(X2=1.004,P=0.316)及牙位方面的差异(X2=0.072,P=0.788)没有统计学意义.结论 上颌第二乳磨牙根管数目存在较多变异,MB2发现率较高.     

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     

The MB3 canal in maxillary molars: a micro-CT study

Objectives

To assess the internal and external morphologies of the mesiobuccal (MB) root of maxillary molars presenting a third root canal (MB3), using micro-computed tomography (micro-CT).

Material and methods

Two-hundred and sixty-five extracted maxillary first and second molars with different root configurations were imaged in a micro-CT scanner at 19.6-μm pixel size. Sixteen teeth presenting MB3 canal were selected and evaluated regarding root configuration, minimal dentine thickness 2 mm under the furcation area, canal configuration of the MB root, MB3 canal morphology (location, independent or confluent orifice, and anatomy types), and the apical anatomy (aspect ratio, number of accessory canals and foramina, presence of isthmus, and independent MB3 foramen).

Results

Overall, a high variability in canal configuration was detected in the MB root. MB3 canal was observed in 10 maxillary first molars and 6 maxillary second molars (n = 16). Minimal dentine thickness related to the MB3 canal at the coronal third was smaller than that of the MB1 canal. A complex internal anatomy comprising 13 different root canal configurations was observed. A high number of independent MB3 orifices at the pulp chamber floor was observed in the first molars (7 out of 10 teeth), while most of the specimens (n = 14) showed a confluent anatomy of the MB3 canal. A varied number of accessory canals and foramina were observed. At the apical third, isthmus could be observed in 6 specimens, while an independent MB3 foramen was present in 37.5% of the MB roots.

Conclusions

MB3 canal is a rare anatomical variation present in maxillary first and second molars. Its presence can be associated to a complex internal anatomy of the MB root which includes the presence of isthmuses and multiple accessory canals and foramina at the apical third, but also a thin dentine thickness at the coronal third and a confluent anatomy of the MB3 with the other main canals.

     

Evaluating the potential key factors in assessing the morphology of mesiobuccal canal in maxillary first and second molars

The purpose of this study was to provide further information on the morphology of the root canals and pulp chambers of 100 maxillary first and 100 maxillary second molars, with particular reference to the anatomical relationship of the root canal patterns and the distance between mesiobuccal (MB) and mesiolingual (ML) orifices. Each transverse section was digitally imaged to measure the interorificial distance using a stereomicroscope. The angles of primary curvatures were determined in both buccolingual (clinic view, CV) and mesiodistal (proximal view, PV) directions and the canal configuration of the MB root was classified according to the Weine classification. The rhomboidal pulp chamber floor morphology predominated in each tooth type. The mean interorificial distance in both maxillary first and second molars was significantly shorter in type II compared with type III (P < 0.05). The interorificial distance was correlated with the primary curvature of MB canal in PV in maxillary first molars (P < 0.05), whereas the primary curvature of ML canal in CV was correlated with the primary curvature of ML canal in PV in maxillary second molars (P < 0.01). The evaluation of interorificial distance in both types of maxillary molars and the curvature of ML canal in CV in maxillary second molar can give valuable information to the clinician.     

Detection of the second mesiobuccal canal in mesiobuccal roots of maxillary molar teeth ex vivo

AIM: To assess the effectiveness of magnification and dentine removal (troughing) when locating the second mesiobuccal canal in mesiobuccal roots of maxillary molars. METHODOLOGY: A total of 208 extracted human maxillary molars were examined. After crown and pulp removal, the MB1 and 2 canals in the mesiobuccal root were located in three stages that were performed by two undergraduate dental students. Stage 1: canals were located with an endodontic explorer; stage 2: additional canals in the same teeth were located under magnification with a digital microscope (VH-8000, Keyence, Japan); stage 3: additional canals in the same teeth were located by removing dentine (troughing) from the pulp chamber floor within 3 mm from MB1 canal towards the palatal canal with an Enac ultrasonic tip (ST 21, Osada, Japan). In each group, the canals were prepared with Gates Glidden burs and K-files. The distal and palatal roots were then removed, and Indian ink was injected into the canal system within the mesio-buccal root. The root surfaces were washed with 6% NaOCl, and then rendered transparent to observe canal morphology. The root canal configurations were classified into five categories following the modified Weine's classification. RESULTS: More than one canal in the mesio-buccal root was observed in 48% of specimens. Detection rates of multiple canals were 7, 18 and 42% following stages 1, 2 and 3, respectively. There was a significant difference between the stages for detecting the MB2 canal (P < 0.05, Friedman test). CONCLUSIONS: Both magnification (stage 2) and dentine removal under magnification (stage 3) were effective in detecting the presence of the MB2 canal. However, MB2 canals could not be detected in 13% of the teeth because of canal calcification or branching located more apically.     

218颗上颌第一恒磨牙根管的临床观察

作者通过临床治疗对２１８颗上颌第一恒磨牙的根管系统、根管数目、工作长度、根管口分布位置的规律进行观察分析，２１８颗患牙中男性９７颗，女性１２１颗。患者年龄１３～７６岁。近中颊根有２个根管的２８颗，占１２．８４％；根管数目与性别和牙位无显著关系，且随着年龄增长有所减少。从而提出对上颌第一恒磨牙进行牙髓治疗时，应注意根管系统的变异；改进开髓洞形，掌握查找近中颊根第二根管方法，以免遗漏根管。