上颌磨牙近中颊根第二根管的定位与扩通

目的　研究上颌磨牙近中颊根第二根管口 (secondmesiobuccalcanal,MB2 )与近中颊根管口 (mesiobuccalcanal,MB)、腭侧根管口 (palatal,P)的相对位置关系 ;探讨根管显微镜在上颌磨牙MB2治疗中的作用。方法　选取 1 1 3颗上颌磨牙 ,截去牙冠后肉眼寻找并扩通MB2根管 ,然后将未找到MB2或不能扩通的标本利用根管显微镜重复上述操作。对找到MB2根管的标本进行扫描 ,利用Image Proplus 4 .0图像分析软件分析MB2根管口与MB、P根管口的关系。结果　MB MB2距离为(1 47± 0 54)mm ,MB P距离为 (5 77± 0 66)mm ,MB2根管口与MB P连线的垂直距离为 (0 53±0 2 8)mm ,MB P连线与MB MB2连线的夹角 (α)为 2 3 0 7°± 1 3 0 8°。肉眼下有 70颗找到MB2根管口(61 9% ) ,其中 53颗通畅 (46 9% ) ;在根管显微镜下又有 6颗找到MB2 ,其中 4颗MB2根管通畅 ,MB2根管发现率提高 5 4% ;原MB2不通畅的根管又有 2颗通畅 ,MB2根管通畅率提高 5 4%。结论　MB2根管位于MB舌侧 2mm以内及MB P连线近中 1mm以内 ;上颌磨牙MB2发现率为 67 3 % ,其中52 2 %通畅 ;根管显微镜可以提高MB2的发现率及扩通率     

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。     

上颌第一磨牙遗漏近颊第二根管的显微根管再治疗

目的：探讨运用根管显微镜对经治的上颌第一磨牙遗漏近颊第二根管（MB2）的诊治方法。方法：选择需行根管再治疗的上颌第一磨牙64个。依据x线片特征,牙冠与髓底的形态特点判断是否存在MB2。采用斜方形开髓入口,小号K锉探查,必要时使用根管手术显微镜定位MB2根管。镍钛机用根管锉冠向下法预备根管,1％NaOCL冲洗根管系统,冷牙胶侧方加压与热牙胶垂直加压充填根管。记录近颊根根管分型、根管预备过程中并发症的情况,评价疗效。结果：再治疗中共发现MB2根管55个（85．81％）,疏通45个（80％）。近颊根双根管以2—1型、2—2型较常见（76．56％）。治疗过程中未发生器械折断、管壁侧穿等并发症,治疗成功率为95．55％。结论：上颌第一磨牙MB2发生率高,通常狭窄、弯曲、隐蔽,是临床治疗的难点;临床医生有意识地寻找和在显微镜下的可视化操作能提高MB2根管的发现率和治疗的成功率。     

Two canals in mesiobuccal roots of maxillary molars

The purpose of this study was to examine extracted root canal treated maxillary molars cleared for: (i) the presence of a mesiopalatal (MP) canal in both first and second molars, (ii) the extension of MP canal from the pulp to the apical area, and (iii) the incidence of two foramina in the MB root. Seventy-two extracted maxillary molars (42 first and 30 second molars) were root canal treated by graduate students. The mesiobuccal (MB) roots of these samples were rendered transparent using a clearing technique. The results demonstrated that 52.3% of first and 40% of second molars had two canals obturated in the MB root. After clearing the same roots, the presence of MP canals rose to 80.9% and 66.6%, respectively. The MP canals were root canal treated as far as the foramen in 35.2% of first and 35% of second molars. However, after making them transparent, 91.1% and 90% showed the presence of this canal to the anatomical apex. The MB roots of the root canal treated first molars showed the presence of two foramina in 47% of cases but in 88.2% after clearing. The second molars showed 50% and 70%, respectively. The differences between root canal treated teeth before and after clearing were significantly different in almost all comparisons in both first and second molars. The only exception was when the presence of two foramina was compared before and after the clearing process in second molars (McNemar test P < 0.05).     

上颌磨牙近颊第二根管的定位与治疗

目的:探讨上颌磨牙近颊第二根管(second mesiobuccal canal,MB2)的临床发现率、特征及治疗方法.方法:选取患牙髓炎或根尖周炎的上颌第一磨牙106颗、上颌第二磨牙80颗,拍摄术前X线片,探查根管,记录根管数目、形态和类型;采用机动镍钛器械Hero 642进行根管预备,侧向加压充填技术充填根管.结果:上颌第一磨牙、上颌第二磨牙MB2的发现率分别为82.1%和45.0%,多数MB2根管细小,用8或10号锉结合EDTA溶液可通畅根管.根管预备中有1枚器械折断,无其它并发症发生.结论:上颌第一磨牙MB2的发现率高于上颌第二磨牙,多数MB2根管口隐蔽,根管细小;机动镍钛器械预备可获得良好的成形效果.     

上颌磨牙近中颊根第二根管的检出率

目的 探讨上颌磨牙近中颊根第二根管(MB2)的临床检出率以及手术显微镜在提高上颌磨牙临床检出率中的作用.方法 选取进行常规根管治疗的63颗上颌第一磨牙.27颗上颌第二磨牙,以及进行显微根管治疗的55颗上颌第一磨牙,20颗上颌第二磨牙,2颗上颌第三磨牙,分别拍摄术前X线片,探查根管,记录根管数目.结果 进行常规根管治疗的上颌第一磨牙和上颌第二磨牙,MB2检出率分别为28.6%和3.7%;进行显微根管治疗的上颌第一磨牙和上颌第二磨牙,MB2检出率分别是61.8%和25%:对上颌第一磨牙常规根管治疗和显微根管治疗的MB2临床检出率进行卡方检验,X2=13.17,差异有统计学意义(P<0.001);对上颌第二磨牙常规根管治疗和显微根管治疗的MB2临床检出率进行Fisher确切概率值检测,单侧比较值为0.043,差异有统计学意义(P<0.05).结论 手术显微镜有助于提高上颌磨牙MB2的临床检出率,选择显微根管治疗有助于提升上颌磨牙根管治疗的成功率.     

Clinical investigation of second mesiobuccal canals in endodontically treated and retreated maxillary molars

An examination of 1873 conventionally treated and retreated maxillary first and second molars was made in an attempt to determine the percentage of second mesiobuccal (MB2) canals that could be located routinely and evaluate if there were any significant differences between initial treatments and retreatments. The teeth examined were 1193 first molars and 680 second molars treated consecutively over a 2-yr period by five endodontists. Overall the MB2 canal was found in 724 (61%) first molars and 245 (36%) second molars. The incidence of a MB2 canal in first molar retreatments was 67% compared to a 59% incidence in initial treatments. Whereas in second molars, the retreatment incidence was 44% compared with 35% in initial treatments. The significant difference in the incidence of a MB2 canal between initial treatments and retreatments suggests that failure to find and treat existing MB2 canals will decrease the long-term prognosis.     

Identification of second canals in the mesiobuccal root of maxillary first and second molars using magnifying loupes or an operating microscope

Various authors have investigated the frequency of second canals (MB2) in the mesiobuccal roots of maxillary molars, predominantly first molars. Further, it has been reported that the percentage of MB2 canals that are treated during routine endodontic therapy is much lower than the number of second canals identified in vitro. It was the purpose of this study to investigate whether the use of an operating microscope may improve the diagnosis of MB2 canals in mesiobuccal roots of maxillary molars. The canal orifices of 100 maxillary first and second molars (50 of each) were initially inspected by Examiner 1 using individually-adapted x2 magnifying loupes. Subsequently, all teeth were examined by a second investigator using an operating microscope (OPM) with x8 magnification. Finally, the mesiobuccal roots of all teeth were separated. Then, the sections were analysed histologically and by SEM. The histological investigation revealed a total number of 63 MB2 canals, 39 in first, and 24 in second molars. Only 26 (41.3%) of those canals were identified using magnifying loupes, whereas 59 (93.7%) were found by means of an operating microscope.     

Frequency of second mesiobuccal canals in maxillary molars as determined by use of an operating microscope: a clinical study

Operating microscopes have recently been introduced to facilitate treatment of surgical and nonsurgical endodontic cases. The aim of this study was to determine in an in vivo clinical study if the use of an operating microscope would increase the number of second mesiobuccal canals located and obturated in maxillary first and second molars. Two hundred maxillary first and second molars treated with the aid of a microscope were evaluated. The number of second mesiobuccal canals that could be negotiated and obturated within 4 mm of the apex was recorded. Thirty percent of all maxillary molars had a negotiable second mesiobuccal canal. Evaluated separately, 33.1% of the maxillary first molars and 24.3% of the second molars had a negotiable second mesiobuccal canal. Results indicated that use of a surgical microscope did not increase the number of second mesiobuccal canals located, compared with those reports where access preparations were modified and the microscope was not used.     

上颌第一磨牙近颊第二根管的临床治疗

目的 探讨上颌第一磨牙近烦第二根管（second mesiobuccal canal，MB2）的特征及临床治疗方法。方法 选取患牙髓炎或根尖用炎的上颌第一磨牙95颗，拍摄术前X线片，术中采用小号K锉配合15％EDTA溶液探查根管，记录根管数目、形态和类型；采用机动镍钛器械Hero642进行根管预备，侧向加压充填技术充填根管。结果上颌第一磨牙MB2的发现率为81．1％，扩通的MB2占72．6％，多数MB2根管细小弯曲，需用小号锉配合使用EDTA进行疏通，机动镍钛器械预备根管无明显并发症。结论上颌第一磨牙MB2的发生率高，多数根管细小弯曲，小号K锉配合EDTA疏通根管，机动镍钛器械预备可获得良好的治疗效果。     

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。     

Efficacy of clinical and radiological methods to identify second mesiobuccal canals in maxillary first molars

Abstract

Introduction. The success of endodontic treatment depends on the identification of all root canals. Technological advances have facilitated this process as well as the assessment of internal anatomical variations. The aim of this study was to compare the efficacy of clinical and radiological methods in locating second mesiobuccal canals (MB2) in maxillary first molars. Methods. Fifty patients referred for analysis; access and clinical analysis; cone-beam endodontic treatment of their maxillary first molars were submitted to the following assessments: analysis; access and clinical analysis; cone-beam computed tomography (CBCT); post-CBCT clinical analysis; clinical analysis using an operating microscope; and clinical analysis after Start X ultrasonic inserts in teeth with negative results in all previous analyses. Results. Periapical radiographic analysis revealed the presence of MB2 in four (8%) teeth, clinical analysis in 25 (50%), CBCT analysis in 27 (54%) and clinical analysis following CBCT and using an operating microscope in 27 (54%) and 29 (58%) teeth, respectively. The use of Start X ultrasonic inserts allowed one to detect two additional teeth with MB2 (62%). According to Vertucci's classification 48% of the mesiobuccal canals found were type I, 28% type II, 18% type IV and 6% type V. Statistical analysis showed no significant differences (p > 0.5) in the ability of CBCT to detect MB2 canals when compared with clinical assessment with or without an operating microscope. A significant difference (p < 0.001)was found only between periapical radiography and clinical/CBCT evaluations. Conclusion. Combined use of different methods increased the detection ofthe second canal in MB roots, but without statistical difference among CBCT, operating microscope, Start X and clinical analysis.     

Root canals in one-rooted maxillary second molars.

The Royal Dental College, Copenhagen, houses an extensive collection of human teeth extracted in Denmark. The collection currently contains 104 one-rooted, permanent maxillary second molars. The root complex on these teeth was sectioned at the junction between the coronal and the apical halves, i.e. mid-root, and at the junction between the middle and the apical thirds, i.e. apically. Using a stereomicroscope we then registered, mid-root and apically, the following variables: canal number, canal position, and canal cross-section. Mid-root there was 1 centrally located root canal in 25.96% of the teeth examined; 2 canals were observed either mesially and distofacially, mesiofacially and distally, or facially and lingually in 34.62%; 3 canals positioned mesiofacially, distofacially, and lingually were found in 39.42%. At the same level 63.51% of the canal cross-sections were non-circular, whereas 36.49% of the canals had a circular cross-section image. The non-circular canal cross-sections could more specifically be characterized as C-shaped, Y-shaped, hourglass-shaped or the root canal had a greater faciolingual than mesiodistal extension or, respectively, a greater mesiodistal than faciolingual extension. Apically there was 1 centrally located root canal in 35.58%; 2 canals were observed with a position either mesially and distofacially, mesiofacially and distally, or facially and lingually in 37.49%; 3 canals located mesiofacially, distofacially, and lingually were found in 26.92%. At the apical level, 64.32% of the root canal cross-sections were non-circular, whereas 35.68% of the canals showed a circular cross-section. The results presented here are aimed at: clinical dentists, endodontists, and dental morphologists.     

上颌第二磨牙近中颊根第二根管的解剖定位

目的:观察髓室底的解剖形态和根管口的数目和位置,探寻近颊根第二根管(MB2)根管口的定位规律.方法:选择 (7|7)离体牙220 颗,利用耳鼻喉科内窥镜系统对髓室底进行观察,测量髓室底根管口之间的位置关系,统计MB2出现率,探寻MB2根管口定位规律. 结果:髓室底观察发现,MB2基本上发生在MB-P连线的近中舌侧,MB2的发生率为38.2%. MB2-MB的距离为(1.56±0.65) mm.MB-DB的距离为(2.34±0.78) mm, MB-P的距离为(5.05±1.26) mm.∠MB2-MB-P的角度为(22.21±10.35)°. 结论:MB2根管口多位于MB-P连线的近中舌侧,且在以MB为中心, MB-P为一边,向近中做角度为(22.21±10.35)°的扇形范围内基本上能找到MB2.     

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目的    探讨上颌第一磨牙近中颊根第二根管（MB2）的寻找与扩通方法。方法    将2006—2008年于沈阳市口腔医院口内门诊就诊患者的因牙髓炎需要做根管治疗的上颌第一磨牙84颗,随机分成试验组（42颗）、对照组（42颗）。试验组根管显微镜下寻找MB2并扩通,而对照组常规裸眼下进行操作,比较分析两组MB2的发现率及通畅率。结果    试验组上颌第一磨牙MB2发现率、通畅率分别为80.95% 、82.35% ,对照组上颌第一磨牙MB2发现率、通畅率分别为42.86% 、77.78%,两组上颌第一磨牙MB2发现率比较,差异有统计学意义（P < 0.05）,通畅率比较差异无统计学意义（P > 0.05） 。结论    在对上颌第一磨牙进行根管治疗时,用根管显微镜寻找MB2的比例远大于临床用裸眼下操作。     

A 5 yr clinical investigation of second mesiobuccal canals in endodontically treated and retreated maxillary molars

An examination of 5616 endodontically treated and retreated maxillary first and second molars was made in an attempt to determine the percentage of MB2 canals that could be located routinely, and evaluate if there were any significant differences between initial treatments and retreatments. The teeth examined were 3578 first molars and 2038 second molars treated consecutively over a 5-yr period by six endodontists. Overall the MB2 canal was found in 2133 (60%) first molars, and 712 (35%) second molars. The incidence of a MB2 canal in first molar retreatments was 66% compared to a 58% incidence in initial treatments. Whereas in second molars the retreatment incidence was 40% compared to 34% in initial treatments. The significant difference in the incidence of a MB2 canal between initial treatments and retreatments suggests that failure to find and treat existing MB2 canals will decrease the long-term prognosis.     

Root canals in one-rooted maxillary second molars

The Royal Dental College, Copenhagen, houses an extensive collection of human teeth extracted in Denmark. The collection currently contains 104 one-rooted, permanent maxillary second molars. The root complex on these teeth was sectioned at the junction between the coronal and the apical halves, i.e. mid-root, and at the junction between the middle and the apical thirds, i.e. apically. Using a stereomicroscope we then registered, mid-root and apically, the following variables: canal number, canal position, and canal cross-section. Mid-root there was 1 centrally located root canal in 25.96% of the teeth examined; 2 canals were observed either mesially and distofacially, mesiofacially and distally, or facially and lingually in 34.62%; 3 canals positioned mesiofacially, distofacially, and lingually were found in 39.42%. At the same level 63.51% of the canal cross-sections were non-circular, whereas 36.49% of the canals had a circular cross-section image. The non-circular canal cross-sections could more specifically be characterized as C-shaped, Y-shaped, hourglass-shaped or the root canal had a greater faciolingual than mesiodistal extension or, respectively, a greater mesiodistal than faciolingual extension. Apically there was 1 centrally located root canal in 35.58%; 2 canals were observed with a position either mesially and distofacially, mesiofacially and distally, or facially and lingually in 37.49%; 3 canals located mesiofacially, distofacially, and lingually were found in 26.92%. At the apical level, 64.32%. of the root canal cross-sections were non-circular, whereas 35.68% of the canals showed a circular cross-section. The results presented here are aimed at: clinical dentists, endodontists, and dental morphologists.     

上颌第二磨牙近中颊根MB2根管的临床研究

目的研究上颌第二磨牙近中颊根第二根管的临床发现率。方法采用改良髓腔入口和探查近中颊根根管口与腭根根管口之间发育沟或暗线的方法研究上颌第二磨牙近中颊根第二根管的肉眼发现率。结果60例患者的64颗上颌第二磨牙中有19颗存在近中颊根第二根管，发现率为29．7％。结论改良髓腔入口和探查近中颊根根管口与腭根根管口之间发育沟或暗线的方法，有利于发现和治疗上颌第二磨牙近中颊根第二根管。