下颌第二磨牙C形根管的观察

目的:观察下颌第二磨牙C形根和C形根管的形态。方法:将离体下颌第二磨牙塑料包埋后每距1.0mm水平片切,观察其牙根及根管形态。结果:62个下颌第二磨牙中C形牙根的发生率为3 2 .2 6% ,均在颊侧发生融合。根管变异较多,仅2 0 %从根颈至根尖为完整的C形,其余的整个行程中C形、分号形、分离形可相互发生转变。结论:下颌第二磨牙根管变异较多。     

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目的观察下颌第二磨牙牙根、牙根不同部位根管数目及形态,为根管治疗提供依据。方法选取2006年1月至2008年4月首都医科大学附属北京中医医院口腔科门诊中因各种原因拔除的下颌第二磨牙166颗,观察牙根数目及形态后,将牙根切为根上1/3,根中1/3和根尖1/3。观察不同部位的根管数目及形态。结果下颌第二磨牙单根12颗(7.2),双根101颗(60.8),其中近中根1-1型根管48颗(47.5),2-1型30颗(29.7),1-2型18颗(17.8),2-2型5颗(5)。远中根1-1型根管88颗(87.1),2-1型2颗(2.0),1-2型4颗(4.0),2-2型7颗(6.9)。C形根53颗(32.0),其中只有26颗具有C形根管(49)。166颗患牙中C形根管的总检出率为15.7。结论下颌第二磨牙牙根及根管数目、形态变异较多,C形根管的存在给根管治疗带来困难,不利于根管的彻底清理和充填。     

C-shaped root canals in mandibular second molars in a Chinese population

Abstract The purpose of this investigation was to study the prevalence of C-shaped roots, root canal orifices, and root canals in the mandibular second molars of a Chinese population. A total of 581 second mandibular molars were collected in Hong Kong and Taiwan. The teeth were demineralized and placed in methyl salicylate to induce transparency. The pulp chamber floor was examined to ascertain the number of root canal orifices. Chinese ink was then injected into the root canal system to demonstrate the root canal anatomy. The mandibular second molars had separate roots in 66.4%, cone-shaped roots in 2.1% and C-shaped roots in 31.5%. The C-shaped roots had C-shaped canal orifices in 68.3% (21.5% of whole material). True C-shaped root canals were observed in 65.8% of the teeth with C-shaped orifices and in 13.9% of the whole material. Separate root canals were seen in 34.2% of the teeth with C-shaped orifices. Separate canal orifices were found in 31.7% of the C-shaped roots and 7.4% of these roots had true C-shaped canals. In the whole material 0.9% of the roots with individual canal orifices had C-shaped canals. In conclusion, C-shaped root canals were common in mandibular second molars in the Chinese subjects studied. The C-shaped root canals were often, but not always recognized because of a C-shaped canal orifice.     

离体上颌第二前磨牙根管和牙根情况的研究

目的观察上颌第二前磨牙的牙根及根管形态。方法213颗离体的上颌第二前磨牙，对牙齿进行近远中向X线照像，并从根中1／3横断探测确实，Vertueei’s分类法对根管系统进行记录。结果185颗牙是单根(87％)，28颗牙是双根(13％)，而单根牙中最多的是1个根管[Type Ⅰ(1)]，占牙齿总数的43％，其次是单根双管TypeⅡ(2-1)，即颊舌2个根管，至根尖又合并成一个根尖孔，占牙齿总数的35％。结论上颌第二前磨牙主要是单根，单个根尖孔的发生率高(78％)。     

下颌第二磨牙C形根管的特点和临床治疗

目的探讨下颌第二磨牙C形根管的发生率、临床诊断和治疗方法。方法通过对152例下颌第二磨牙拍摄术前X线片和术中根管探查,按照Melton标准诊断C形根管;采用机用镍钛器械Hero642进行根管预备,次氯酸钠超声冲洗,热牙胶垂直加压技术充填根管。记录C形根管的发生率及临床特点,根据治疗前、中、后的X线片评价根管预备和充填的效果。结果下颌第二磨牙C形根管的发生率为32.2%,79.6%的C形根管患牙X线片表现为锥形融合牙根,20.4%表现为近、远中独立牙根;所有患牙均无根管内并发症发生,治疗效果好。结论下颌第二磨牙C形根管主要存在于融合牙根,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、次氯酸钠超声冲洗和垂直加压技术充填根管可获得良好的治疗效果。     

口腔锥形束CT在下颌第二磨牙C形根管诊治中的应用

目的探讨口腔锥形束CT(cone-beam computed tomography,CBCT)在根管治疗中诊断治疗下颌第二磨牙C形根管的临床应用。方法选取初次根管治疗失败的下颌第二磨牙62颗,根尖片不能确定根管解剖形态以及可疑遗漏根管,患牙采用CBCT进行扫描三维重建。结果使用CBCT确定下颌第二磨牙中52颗为C形根管,C形根管发生率达83.87%,C形根管中28颗为C1型变异根管(53.84%),18颗为C2型变异根管(34.62%),6颗为C3型变异根管(11.54%)。52颗患牙除2颗因根管侧穿导致根管治疗失败外,其余50颗患牙通过热牙胶充填与垂直加压技术将软化的牙胶充入不规则的根管系统,达到严密充填根管,根管再治疗后患牙成功治疗的有50颗(96.15%),均无不适症状。CBCT在根管治疗中辅助定位变异根管,定位准确率较高。结论 CBCT影像精密度高,可从三维角度分析根管,在根管治疗中诊断治疗下颌第二磨牙C形根管具有临床指导意义。     

下颌第二磨牙扇形根管的出现率与牙根形态的关系

目的：调查下颌第二磨牙扇形根管的出现率与牙根形态的关系。方法：通过进行根管治疗的202个下颌第二磨牙的临床检查，对其牙根形态和根管形态分类计数，调查扇形根管的出现率。结果：分叉根的扇形根管出现率为18．7％，平行根为35．5％，锥形根为76．3％。结论：近中根与远中根相距越近，扇形根管的出现率越高。     

应用锥形束CT研究下颌第二磨牙根管数目和构型

目的采用锥形束CT（cone-beam computed tomography,CBCT）观察下颌第二磨牙根管数目及构型,为根管治疗提供影像学参考。方法随机调取700颗下颌第二磨牙的CBCT资料,统计下颌第二磨牙牙根数目、根管数目和构型,以及C型根管的发生率。结果下颌第二磨牙c形牙根的发生率为36．O％;2根牙的根管构型：61．1％近中根管为Ⅳ型,96．1％远中根管为I型;C形根管在根管口及根尖1／3处类型变化多。结论下颌第二磨牙牙根和根管解剖形态多样,CBCT清晰的三维影像能为根管治疗提供参考。     

Differences in the confluence of mesial canals in mandibular molar teeth with three or four root canals

Aim  To investigate the correlation between number of root canals and their confluence in mandibular molar teeth.
Methodology  A total of 553 first and 383 second mandibular molars were root filled between the beginning of 1997 and the end of 2006. Access cavities were prepared and the pulp chamber floors were carefully inspected with an endodontic explorer under magnification of 4×. After negotiating the root canal system, the 'straightest' canal of each root was instrumented. A gutta-percha cone was placed in the canal and a small file (08 or 10) was inserted to working length and then removed in all other canals. The gutta-percha cone was removed and inspected for notches indicating the presence of confluences. If it was not possible to probe completely one or more canals, the canal confluences were classified as 'not determined' (ND) if there was no sign of confluence; if a notch was present canals were considered confluent. For each tooth, the number of root canals and the presence of confluences were recorded. To test whether there was a difference in frequency of confluences between teeth with three and four root canals the chi-squared analysis with Yates' continuity correction was performed.
Results  The frequency of a confluence in mesial canals of first molars was 56% in teeth with three root canals and 34% in teeth with four canals. In second molars, it was 67 and 41%, respectively. Differences in the frequency of confluences in teeth with three and four root canals were statistically significant both in first and in second molars.
Conclusions  A greater incidence of confluent canals occurred in teeth with three rather than with four root canals both in first and second mandibular molars.     

Two palatal root canals in a maxillary second molar

In this study, we report a case of two palatal root canals in a maxillary second molar that was endodontically treated. The possibility of two palatal root canals in maxillary second molars is quite small; however, it must be taken into account in clinical and radiographic evaluation during endodontic treatment. Often, their presence is noticed only after a canal treatment due to continuing post-operative discomfort.     

GuttaFlow常温流动牙胶在下颌第二磨牙C形根管中的应用

目的 评价GuttaFlow 常温流动牙胶在下颌第二磨牙C形根管中的疗效。方法 选择需要治疗的下颌第二磨牙C形根管76例80颗牙,随机分为两组,每组40颗牙,实验组常温流动牙胶+牙胶尖充填根管,对照组碧兰糊剂+冷牙胶尖侧压充填根管。比较两组在充填时间、X线片根管充填质量、术后1周内疼痛以及术后1年复查疗效。结果 实验组充填时间平均每根管65 s,对照组425 s;实验组术后疼痛3例,对照组16例;实验组根管适充37颗牙（92.5%）,对照组根管适充29颗牙（72.5%）。实验组成功39例（97.5%）,对照组成功32例（80.0%）,两组差异有显著性（P<0.05）。结论 常温流动牙胶在下颌第二磨牙C形根管中充填简便疗效显著,值得在临床上推广应用。     

The prevalence of second canals in the mesiobuccal root of maxillary molars: A cone beam computed tomography study

The aim of this study was to determine the prevalence of MB2 canals in permanent maxillary molars utilising CBCT; in patients attending a university hospital. A total of 200 patient scans, (100 female and 100 male patients), were enrolled in the study. In total, 800 teeth were analysed, and teeth with additional canals in their MB roots (MB2) were identified. First maxillary molar teeth exhibited the highest prevalence of MB2 canals, 92% and 87%, for teeth 16 and 26, respectively. Second maxillary molar teeth showed a lower prevalence of MB2 canals, 69% and 65%, for the 17 and 27, respectively. There were no associations of significance between the prevalence of MB2 canals and patient age or gender. Root morphology and anatomy of permanent maxillary first and second molar teeth was found to be highly variable. The prevalence of additional canals in the MB roots is a frequent finding which has previously been underreported.     

下颌第二磨牙C形根管水平投照X线影像特点

目的探讨下颌第二磨牙C形根管水平投照x线影像特点。方法对77颗离体下颌第二磨牙进行水平投熙，两周后集中读片，将x线表现与离体牙牙根、根管形态和分型情况进行比较，总结离体牙C形根管水平投照x线影像特点。结果具C形根管的下颌第二磨牙的水平投照X线影像在牙根、髓腔、根管三方面有共同特点。牙根影像：①牙根影像呈单根，根尖锥形或结节状，中间有条索状或棒锤状X线低密度区；②似双根，根尖呈较宽的方圆形，“两根”之间由X线密度降低区连接，X线低密度区由根分歧处较窄渐向根尖区轻度增宽，“两根”尖部较圃钝。髓腔影像：髓腔深窄，髓室底近远中根管口距离近，一般不大于髓室底水平处牙根直径的1／3。根管影像：双根管或三根管影像，在根尖1／3汇合，或者有靠近趋势后又分开。除外粗大单根管影像。结论下颌第二磨牙C形根管X线影像具有一系列特点，对临床判断有一定帮助。     

Mandibular permanent second molar with four roots and root canals: a case report

Although four-rooted mandibular first molars have been observed on a few occasions in the literature, to the best of our knowledge, four-rooted second molars have not been reported. Here, we describe a mandibular second molar with four roots and canals: two mesial and two distal. Mesial roots were separated in the cervical one-third near the cervical margin, while distal roots were divided at a lower level in the middle one-third of the root. We discuss the possibility of different root and canal variations of the mandibular second molar from a developmental point of view.     

下颌第二前磨牙双根3根管治疗1例

下颌前磨牙根管形态较为复杂,可能存在多根管,给根管治疗带来难度.插诊断丝的X线片,和多角度投射有助于发现其他根管.CBCT可更加直观的看到根管形态,从而有利于分析根管的分布.报告1例CBCT在下颌第二前磨牙双根3根管治疗中的诊断作用.     

Mandibular molar with three distal root canals

Abstract An unusual case is presented in which there were three canals in the distal root of a mandibular first permanent molar. The anomaly was not detectable radiographically, but could be important during root canal treatment. The variation may be related to the occurrence of a contralateral three-rooted molar seen in the patient.     

Number of roots and canals in maxillary first premolars: study of an Andalusian population

Abstract— A study of 150 extracted maxillary first premolars from citizens of Seville, Andalusia, southern Spain, revealed 60 teeth with one root (40.0%), 85 teeth with two roots (56.7%) and five teeth with three roots (3.3%). The distribution of root canal shapes in the sample showed that all teeth with two or three roots had type I root canals (each canal had one apical foramen). Conversely, most of the single-rooted maxillary first premolars had root canal shape type II (two canals converging in the same apical foramen). Only 1.3% of the teeth had a unique orifice in the pulp chamber and only one root canal. These results emphasized the importance of good knowledge of the root canal morphology and the need for a careful radiographic examination as part of competent root canal therapy of maxillary first premolars.     

The maxillary second molar: variations in the number of roots and canals

A retrospective study was undertaken of 520 completed endodontic treatments of maxillary second molar teeth which were selected from a specialty endodontic practice. Radiographs were reviewed and studied, a classification of antomical root and canal variations was devised, and the frequency with which each variant occurred was recorded. There were six variants which occurred frequently enough to be considered as separate anatomic categories and their frequency of occurrence is illustrated. The six variants found in the study and their frequency of occurrence are as follows: (1) three separate roots and three separate canals (56.9%); (2) three separate roots and four canals (two in the mesiobuccal root) (22.7%); (3) three roots and canals whose mesiobuccal and distobuccal canals combine to form a common buccal with a separate palatal (9%); (4) two separate roots with a single canal in each (6.9%); (5) one main root and canal (3.1%); and (6) four separate roots and four separate canals including two palatal (1.4%). Clinical examples of these deviant variations are also presented.     

Leakage along warm gutta-percha fillings in the apical canals of curved roots

Abstract – The aim of this study was to investigate the leakage along the apical portion of warm gutta‐percha obturated curved canals. Human mandibular premolars with single, curved (21°–40°) canals were prepared using the Lightspeed technique. Two groups of prepared canals, matched according to curvature and prevalence of apical transportation, were obturated by two techniques. Coronal gutta‐percha was removed immediately after root obturation was completed to simulate the procedure for post space preparation. Leakage along the apical 3 mm of root filling was measured with a fluid transport device. Vertical condensation of warm gutta‐percha and Pulp Canal Sealer provided less leakage than Thermafil plastic obturators and AH26 sealer (P=0.002).