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。     

上颌磨牙近中颊根根管截面形态的研究

目的：研究国人离体上颌第一、二磨牙近中颊根根管的内径和截面形态，为临床进行上颌磨牙根管治疗提供理论参考。方法：收集离体上颌第一磨牙108个，上颌第二磨牙167个。自根管口水平截取近中颊根，包埋。自根尖面开始每隔1mm横切牙根至距根尖6mm处，第7个横切面平近中颊根的根管口水平面。根管显微镜（DOM）下观察、拍摄每个牙根的7个切片的冠面，记录每个冠面含有的根管数，测量各截面各根管的颊舌径和近远中径，并按标准记录根管截面形状。结果：上颌第一磨牙共截取756个切片，均见近中颊根主根管（MB），464个切片中可观察到近中颊根第二根管（MB2）；上颌第二磨牙共截取1169个切片，含MB共1169个，MB2共442个；含MB2的标本数在上颌第一磨牙和第二磨牙分别为96个和90个，占88．89％和53．89％。近中颊根主根管（MB）的颊舌径多大于近远中径，截面形状以扁形和椭圆形多见，但愈近根尖，两径间的差距愈小，即MB愈近根尖，愈趋向成圆形：近中颊根第二根管（MB2）的颊舌径和近远中径间的差距变化不大，截面形状以圆形最多，椭圆形次之，扁形最少。结论：上颌第一、二磨牙近中颊根的根管截面形态复杂，提示临床上需配合有效的清理和成形技术以提高该牙位的根管治疗成功率。     

上颌第二磨牙近颊根根管形态的研究

目的:运用透明牙技术研究上颌第二磨牙近颊根根管形态。方法:收集离体上颌第二磨牙70颗,先去除牙髓,根管内注入印度墨水,经10%硝酸脱钙,酒精梯度脱水,于99%水杨酸甲酯中透明,在放大镜下观察根管形态,按Vertucci标准对根管分类。结果:70颗上颌第二磨牙中67颗为三根牙,占95.71%。67颗三根牙的腭根和远颊根均为单根管,近颊根单根管率为55.22%。70颗上颌第二磨牙中,近颊第二根管(MB2)的发生率为42.86%,其根管类型以Ⅱ型(2-1)和Ⅳ型(2-2)为主。结论:上颌第二磨牙近颊根根管形态复杂,对其解剖形态熟练掌握,能够提高该牙根管治疗的成功率。     

蒙古族上颌磨牙近中颊根根管分型及其临床意义

目的：运用透明牙标本技术研究蒙古族人离体上颌第一、二磨牙近中颊根（MBR）的根管分型。方法：收集蒙古族人离体上颌第一磨牙55例和第二磨牙61例,制成透明牙标本,观察蒙古族上颌磨牙MBR的根管分型情况。结果：蒙古族上颌第一磨牙MBR的根管分型以2-2型和2-1型为主,在55例中分别占29.09%和25.45%,其次为1-1型占18.18%,而2-1-2型、1-2型、变异型及1-2-1型分别占10.91%、9.09%、5.45%和1.82%;在52例有独立MBR形态的蒙古族上颌第二磨牙中,1-1型和2-1型最多见,分别占32.69%和26.92%,其次为2-2型和2-1-2型,各占13.46%,1-2型及1-2-1型分别占11.54%和1.92%。结论：掌握蒙古族上颌磨牙MBR的2-1-2型和1-2型根管形态,是提高蒙古族上颌磨牙根管治疗成功率的关键。     

锥体束CT对上颌第一磨牙近中颊根管形态的研究

目的：通过锥体束CT（cone--beam computed tomography,CBCT）成像系统分析上颌第一磨牙近中颊根根管形态及第二（second mesiobuccal,MB2）根管的发生率。方法：选择95名进行CBCT扫描的患者,共计180颗上颌第一磨牙,观察近颊根根管形态、MB2根管的发生率、左右侧发生比率及男女发生比率差异。结果：上颌第一磨牙近颊根管形态以Ⅲ型为主,MB2根管发生率为79．4％,左右侧发生比率无统计学差异（P=0．846）,男性发生率明显高于女性（P=0．043）。结论：上颌第一磨牙近颊根MB2根管的发生率较高,可通过CBCT有效的发现MB2根管,为临床诊疗提供依据。     

上颌第一磨牙近中颊侧第二根管的诊断及治疗

目的探讨上颌第一磨牙近中颊侧第二根管的临床发现及治疗效果。方法选择有近中颊侧第二根管的上颌第一磨牙根尖周炎、牙髓炎患者共20例，通过X线片及临床经验寻找并确诊近中颊侧第二根管。采用常规逐步后退法预备根管，侧方加压充填根管。结果20颗患牙经完善的根管治疗后6、12个月复诊，患者无主观症状，咀嚼功能良好，X线检查原有根尖阴影明显缩小，或未见新的根尖病变发生，临床疗效均为成功。结论术前、术中、术后的X线片对上颌第一磨牙近中颊侧第二根管的诊断及治疗有较大帮助。     

上颌磨牙近中颊根第二根管定位与扩通的研究

上颌磨牙常因近中颊根第二根管(the second mesiobuccal canal,MB2)的遗漏而导致上颌磨牙根管治疗失败.因而如何通过有效辅助手段发现、定位及扩通MB2成为临床医师所关注的问题.本文就上颌磨牙MB2的研究现状及根管显微镜在定位与扩通上颌磨牙MB2中的辅助作用作一综述.     

使用手术显微镜对上颌第一磨牙近中颊侧第二根管应用解剖的研究

目的：使用手术显微镜（operating microscope,OM）研究上颌第一磨牙近中颊侧第二根管口（MB2）形态和解剖位置关系，为根管治疗时寻找根管口提供解剖学依据。方法：采用UNIVERSA300/FS2012手术显微镜，观察110个上颌第一磨牙的MB2根管口形态及其发生率。结果：上颌第一磨牙的MB2出现率为38%；根管口的形态为圆形和卵圆形。结论：使用手术显微镜可以有效地发现MB2。     

上颌第一磨牙近中颊根的解剖形态研究

目的：研究上颌第一磨牙（16、26）近中颊根的解剖形态，为临床治疗提供参考。方法：使用透明标本法，将132个离体16、26制成透明牙，观察其近中颊根的牙根外形与根管形态，比较并分析两者间的关系。结果：16、26近中颊根的牙根外形按照融合角度和分叉情况的不同分为4型：Ⅰ～Ⅳ型牙根的百分比依次为40.91％、23．48％、23．48%和12．12％。根管形态按Weine法分为4型：1-1型、2—1型、1—2型、2—2型，发生率依次为32．58％、17．42％、12．12％和37．88％。并对根管的锥度和弯曲角度进行了探讨。结论：16、26近中颊根的牙根外形与根管形态间有着密切的关系，掌握其形态学规律具有重要的临床意义。     

Canal configuration in the mesiobuccal root of the maxillary first molar: a descriptive study

This study investigated the morphology of the mesiobuccal root of the maxillary first molar. One hundred ten extracted maxillary first molars were accessed. The first and second mesiobuccal canals were exposed, soaked in black India ink, decalcified, dehydrated, and made transparent. The configurations of the root canals in the mesiobuccal root were studied under magnification (2.6x) and classified according to Weine's four types of root canal configurations. Under the conditions of this study, a high percentage of second mesiobuccal canals were revealed.     

Canal configuration of the mesiobuccal root of the maxillary first molar of a Japanese sub-population

AIM: The aim of this study was to determine the percentage of anatomical canal configurations of the mesiobuccal root of the maxillary first molar in Japanese patients. METHODOLOGY: Three hundred teeth were obtained from general dentists who knew absolutely that they were extracted from Japanese patients. The distobuccal and palatal roots were amputated for radiographic convenience. Preoperative radiographs were taken of the remaining crown and mesiobuccal root (MBR) from mesiodistal and buccopalatal directions for each tooth. Routine endodontic access cavities were prepared and size 08 files were placed through the orifice into the MBR until they were seen at the apex. In some cases preparation of the canal orifice with a long shank round burr was necessary to gain access. In seven teeth, no access to the apex was possible and these teeth were eliminated. In the other 293 teeth, the MBR canal(s) was (were) enlarged up to size 15 file. If another canal opening was found at the apex a 08 file was inserted into the second opening and passed coronally. Postoperative radiographs with file(s) in place were taken from the two directions, as before. RESULTS: Of the 293 teeth, 123 (42.0%) were Type II, 89 (30.4%) showed Type III systems and 10 (3.4%) were Type IV. Suggestions for identification and treatment of the second canal in the MBR are presented. CONCLUSIONS: The proportion of cases with two canals in the mesiobuccal root of maxillary first molars from Japanese patients was high and similar to that described from studies of other ethnic populations.     

Canal configuration of the mesiobuccal root of the maxillary first molar: conventional and surgical approaches

One of the primary causes of endodontic failure is the presence of untreated canals. Although the maxillary first molar has been described as the most endodontically treated tooth, the canal configuration has been the least understood. The purpose of this article is to present, with the aid of several clinical cases, a review of the literature regarding the frequency, the location, and the incidence of the second mesiobuccal canal in relation to the maxillary first molar, both for conventional and surgical approach.     

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。     

Three-dimensional analysis of mesiobuccal root canal of Japanese maxillary first molar using Micro-CT

The objective of this study was to three-dimensionally observe the morphological characteristics of mesiobuccal root canals of Japanese maxillary first molars using microcomputed tomography (Micro-CT) and classify root canal variations. This study used 90 maxillary first molars. Three-dimensional reconstruction was performed using data obtained by Micro-CT, and cross-sections of the root canals were observed. Moreover, the root canal morphology was classified by the configuration and root canal diameter, and was evaluated for occurrence using the classification by Weine et al. (1969) as a reference. Overall, single root canals were observed in 44.4%, incomplete separation root canals in 22.3%, and completely separate root canals (upper and lower separation root canals) in 33.3%. Mesiobuccal root canals often had intricate configurations, and accessory root canals (lateral canals and apical ramifications) were observed in most of the mesiobuccal root canals (76.7%), irrespective of whether there were ramifications of the main root canals. While there were no marked differences in the incidence of root canal ramifications between this study and earlier reports, the incidence of accessory root canals was higher in this study. This result may be explained by the far more superior visualization ability of Micro-CT than conventional methods, which allowed the detection of microscopic apical ramifications previously difficult to observe.     

Three canals in the mesiobuccal root of a maxillary first molar: a case report

This article describes the identification and treatment of a maxillary first molar exhibiting three canals in the mesiobuccal root. An 18-yr-old male patient presented for nonsurgical root canal therapy of tooth #3. After accessing the pulp chamber, and probing with 2.5x magnification, only one canal was located in the mesiobuccal root initially. Subsequent to troughing the groove between the mesiobuccal and palatal canals with a #2 round bur, two additional canals were located. An electronic apex locator was utilized to ensure a perforation of the pulpal floor had not occurred. A working film confirmed the presence of three canals in the mesiobuccal root, and the canals were cleaned, shaped, and obturated.