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.     

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。     

根管显微镜在定位上颌磨牙近颊根第二根管中的作用

目的:评价改进开髓口和应用根管显微镜(DOM)定位离体上颌第一、二磨牙近颊根第二根管(MB2)的能力.方法:收集离体上颌第一、二磨牙共550颗.在肉眼、传统三角形开髓口(N.E-1),肉眼、改进开髓口(N.E-2)和根管显微镜辅助(DOM)三种不同条件下分别探查根管,记录MB2数目.结果:N.E-1、N.E-2和DOM三种不同条件下,MB2发现率在上颌第一磨牙分别为34.26%、51.85%和78.24%;第二磨牙分别为16.17%、23.65%和41.32%.改进开髓口和使用DOM可显著提高MB2发现率,与传统开髓口间的差别有统计学意义,P＜0.05.结论:建议将上颌磨牙开髓口由传统的三角形改为斜四边形,并使用合适的放大技术和增强照明,以提高MB2发现率和治疗率.     

上颌第一恒磨牙近中颊根根管宽度和锥度测量分析

目的: 测量分析上颌第一恒磨牙近中颊根根管宽度和锥度,为临床提供参考。方法: 收集50颗上颌第一恒磨牙制作透明牙,然后自近中颊根根尖孔处每隔0.4 mm与根管走行方向垂直连续横切,立体显微镜下放大30倍测量各个切片宽度,计算根尖1/3、中1/3、颈1/3各区段的锥度值。结果: 近中颊根第一根管宽度：根尖最大径（0.38±0.12）mm、最小径（0.34±0.16）mm,根中最大径（0.55±0.26）mm、最小径（0.57±0.12）mm,根颈最大径（1.13±0.34）mm、最小径（0.59±0.18）mm。第二根管宽度：根尖最大径（0.25±0.13）mm、最小径（0.28±0.10）mm,根中最大径（0.36±0.09）mm,最小径（0.17±0.06）mm,根颈最大径（0.79±0.23）mm、最小径（0.23±0.17）mm。近中颊根第一根管锥度：根尖1/3最大径0.03 mm、最小径0.01 mm,中1/3最大径0.06 mm、最小径0.03 mm,冠1/3最大径0.10 mm、最小径0.09 mm。第二根管锥度：根尖1/3最大径0.02、最小径-0.01,中1/3最大径0.06,最小径0.00,冠1/3最大径-0.02、最小径-0.02。结论: MB1具有较大的宽度和锥度,且根尖1/3、中1/3、冠1/3锥度不同,而MB2的宽度和锥度都很小,还会出现倒锥度。     

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。     

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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。     

Root and canal morphology of maxillary first and second permanent molar teeth in a Ugandan population

AIM: To investigate the root and canal morphology of permanent maxillary molar teeth from a Ugandan population. METHODOLOGY: Maxillary first (n = 221) and second molar (n = 221) teeth were collected from patients attending dental clinics in Kampala. Teeth were prepared using a clearing technique: the pulp chambers were accessed and the teeth placed consecutively into 5% sodium hypochlorite, 10% nitric acid, then methyl salicylate. Indian ink was injected into the pulp chambers to demonstrate the canal system. RESULTS: In the first molars, 95.9% of the teeth had separate roots. The mesiobuccal root was fused with the palatal root in 3% of specimens and with the distobuccal root in 0.5% of teeth. In the second molars, 86% of the teeth had separate roots. The mesiobuccal root was fused with the palatal root in 6.3% of specimens and with the distobuccal root in 6.8% of teeth. Apical deltas were more frequent in the mesiobuccal root when compared with distobuccal and palatal roots of both the first and second molars. A type I canal configuration (>75%) was the most frequent in all the roots of both the first and second molars. Canal intercommunications and lateral canals were more frequent in the mesiobuccal root when compared with other roots. CONCLUSIONS: The mesiobuccal root tended to have more variations in the canal system followed by the distobuccal root, whereas the palatal root had the least. The findings in root and canal morphology of this Ugandan population were different from previous studies, which may partly be attributed to racial differences.     

上颌第二乳磨牙近中颊根第二根管的临床研究

探讨上颌第二乳磨牙近颊第二根管（MB2）的特征及临床治疗方法。选取患牙髓炎或根尖周炎的上颌第二乳磨牙95颗,拍摄术前及根充后 X 线片,采用耳鼻喉内窥镜观察测量髓室底各根管口位置关系;术中采用10号锉结合17％EDTA 凝胶探查根管,手动器械进行根管预备,螺旋输送器导入 Vitapex 糊剂充填根管。在95颗上颌第二乳磨牙中,有14颗存在 MB2,发现率为14．7％,MB2位于 MB-P 根管口之间假想连线的近中。     

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。     

Root canal morphology of maxillary second molars in a Saudi sub-population: A cone beam computed tomography study

IntroductionRoot morphology and canal anatomy of maxillary molars shows several complexities and variations. Knowledge of these is essential for successful endodontic treatment. This study aimed to investigate the morphology of the maxillary second molars in a Saudi Arabian sub-population in relation to gender, age, and nationality, as well as to analyze the anatomical symmetry between the left and right side in each individual.Methodology420 digitized cone-beam computed tomography (CBCT) scans were collected, of which 351 scans met the inclusion criteria. Number of roots and canals at three different levels of the root in each case was counted at all available sides and compared on the basis of the study variables. Statistical significance was set at P ≤ 0.05.ResultsMost of the patients (n = 323, 92%) had three roots, while two roots (n = 23, 6.6%), four roots (n = 4, 1.1%), and one root (n = 1, 0.3%) were less frequently observed. A significant correlation between female patients and the presence of two canals, while male patients showed a higher correlation with the presence of four canals at all levels. There also was a correlation between Saudi participants and the presence of four canals at all levels. No significant correlation in symmetry between the left and right side root canal anatomy was found. There was an inverse relation between the number of canals and age.ConclusionConsidering the limitations in this study, it appears that the Saudi population is more likely to have three- and two-rooted maxillary second molars, with males and females showing greater tendencies to having three and two roots, respectively.     

Clinical detection of the minor mesiobuccal canal of maxillary first molars

One hundred extracted maxillary first molars from a South East Asian population were sectioned at a level below the roof of the pulp chamber. The detection of the minor mesiobuccal canal was determined on the pulpal floor using a size 08 file. When the canal was not detected by this technique, its presence or absence was then determined by sectioning the mesiobuccal root transversely, and the position of the extra canal was explored from the cut end. It was found that by modifying the outline of the access cavity, and by widening and deepening the groove running palatally from the major mesiobuccal canal up to a depth of 0.5 mm and a distance of 2.0 mm, the visibility of the extra mesiobuccal canal orifice was greatly improved. This study showed that more than 50% of maxillary first molars had a minor mesiobuccal canal, and 19% of these canals could not be detected clinically.     

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.     

Unusual palatal root canal morphology in maxillary molars

Abstract Three clinical cases are presented in which the palatal root(s) of human maxillary molars exhibited root canal morphology characterized by multiple canals/roots.     

上颌第一磨牙根管弯曲度的实验研究

目的:分析上颌第一磨牙根管弯曲位置、方向及弯曲度。方法:收集80个上颌第一磨牙,在根管中分别插入15#-20#扩大针,拍摄近远中向和颊舌向X线片,用Photoshop6.0软件测量根管弯曲位置、方向和弯曲度。结果:上颌第一磨牙腭侧根管通畅、较直。远中颊侧根管80%在近远中方向、45%在颊舌方向有>5°的明显弯曲,弯曲位置多位于根中1/3,且近远中向弯曲度明显大于颊舌向(P<0.05)。近中颊根颊侧根管在近远中方向、颊舌方向分别有82.5%、77.5%出现>5°的明显弯曲。两个方向上的弯曲度无明显差异(P>0.05)。35%的标本探通了近颊根舌侧根管,其在近远中向、颊舌向出现明显弯曲的比例达91%和83%。结论:上颌第一磨牙四个根管在近远中向、颊舌方向均有不同程度的弯曲,其第二弯曲出现的情况也各不相同。     

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。     

上颌第二磨牙的形态学研究

上颌第二磨牙的形态比较复杂且存在变异,临床的解剖位置又比较靠后,给牙髓和牙周病的治疗带来了很大困难。所以,掌握上颌第二磨牙的形态对临床治疗具有指导性的意义。本文系统地回顾了上颌第二磨牙的研究方法和进展,并结合临床对上颌第二磨牙的牙冠和牙根等外部形态以及髓腔和根管形态等内部结构进行了较全面的综述。根管治疗成功的关键是对髓腔解剖的理解和掌握,所以,充分掌握牙根和根管形态并了解可能存在的变异,才能更好地进行治疗。     

头灯放大镜在老年人上颌第一磨牙近颊第二根管治疗中的应用

目的：探讨提高老年人上颌第一磨牙近颊第二根管（MB2）发现率的临床方法.方法：按入选条件随机选取65岁以上老年人需要根管治疗的上颌第一磨牙80颗,分为两组：试验组45颗,用头灯放大镜寻找MB2并记录其发现率和根管找寻时间;对照组35颗,在常规光源下寻找MB2并记录发生率和根管找寻时间,与试验组进行比较.结果：试验组MB2发现率为86.67％、总根管找寻时间为20.13±0.42（分钟）;对照组MB2发现率40％、总根管找寻时间31.21±0.72（min）,两组间MB2发现率及总根管找寻时间存在显著性差异（P＜0.05）.结论：寻找老年人上颌第一磨牙MB2时,头灯放大镜明显优于常规光源,经济实惠、适合临床推广.     

Second mesiobuccal canal detection in maxillary first molars using microscopy and ultrasonics

The aim of this study was to investigate whether the use of operating microscope in combination with ultrasonics increased the rate of second mesiobuccal (MB2) canal detection in permanent maxillary first molar teeth. A hundred extracted human maxillary first molars were assessed. After location of the main canals, the MB2 canal was sought in all teeth first without microscopy, then with the aid of the operating microscope and finally with the combined use of the operating microscope and ultrasonics. With these techniques, the MB2 canal was detected in 62%, 67% and 74% of the teeth, respectively. The combination of the operating microscope and ultrasonics detected significantly more MB2 canals than when no microscopy was utilized (P < 0.05). Sectioning of the roots disclosed the presence of the MB2 canal in 82% of the teeth. Twenty‐nine per cent of the teeth had a separate MB2 canal orifice and separate apical foramina. The results of this study suggested that the combined use of the operating microscope and ultrasonics increased the detection of MB2 canals in maxillary first permanent molars.     

Root canal morphology of the mesiobuccal root of maxillary first molars: a micro-computed tomographic analysis

Aim  To investigate ex vivo , the root canal morphology of the MB root of maxillary first molar teeth by means of micro-computed tomography.
Methodology  Thirty extracted intact human maxillary first molar teeth were selected for micro-tomographic analysis (SkyScan 1072, Aartselaar, Belgium) with a slice thickness of 38.0 μm. The following data regarding the MB root were analysed and recorded: number and type of root canals, prevalence of isthmuses, prevalence of intercanal connections, presence of accessory canals, presence of loops and number of apical foramina.
Results  The MB2 canal was present in 80% of specimens and was independent in 42% of these cases. When present, the MB2 canal merged with the MB1 canal in 58% of cases. Communications between the two canals were found in all specimens, with isthmuses in 71% of the cases. These communications and isthmuses were respectively in 42% and 54% of the cases in the coronal third, in 59% and 79% of the cases in the middle third and in 24% and 50% of the cases in the apical third. A single apical foramen was found in 37% of specimens, two apical foramina were present in 23% of the cases, with three or more separate apical foramina occurring in 40% of the specimens.
Conclusions  The MB root canal anatomy was complex: a high incidence of MB2 root canals, isthmuses, accessory canals, apical delta and loops was found.