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.     

Conventional root canal therapy of C-shaped mandibular second molar. A case report

The C-shaped root canal system and treatment implications were first described by Cooke and Cox in 1979. C-shaped canals are most frequently found in mandibular second molars, but they can occur in any mandibular molar, and they have been reported in maxillary molars as well. C-shaped mandibular molars are characterized by a C-shaped groove that connects one or more root canals. This groove can occur anywhere along the root canal system, making it difficult to diagnose and treat. A C-shaped root canal system may appear completely normal at the level of the pulp chamber but can begin to manifest itself in the middle or apical one-third. Furthermore, C-shaped canals are challenging if not impossible to predict radiographically. C-shaped canals in mandibular second molars are found most frequently in the Chinese population, with reports showing up to a 31.5% incidence, as compared to an approximate 7% incidence in the general population. This case report demonstrates an incidence of a C-shaped canal that was unable to be detected radiographically and which contained three separate root canals that communicated in the apical one-third of the root canal system. Canal orifices were located approximately 2 mm below the level of the CEJ, which is in agreement with a recent micro-computed tomography study of C-shaped mandibular molars that found 98% of all C-shaped molars studied had orifices located 1 mm to 3 mm below the CEJ. The CT study also found that all C-shaped canals contained fused roots and confirmed previous findings that the C-shape configuration varies greatly throughout the length of the canal.     

C-shaped root canal configuration in maxillary first molars

AIM: This clinical report presents the endodontic treatment of two maxillary first molars and the anatomical study of two additional maxillary first molars with a C-shaped distally located root canal system. This configuration is not a common finding. SUMMARY: According to the endodontic literature, the C-shaped root canal is most frequently seen in the mandibular second molar. The occurrence of C-shapes in maxillary first molars, however, has only been described in a limited number of case reports. We observed this configuration in two out of 2175 root-filled maxillary first molars treated at the Department of Endodontology, Ghent University Hospital, during the last 10 years. In order to study and visualize this particular aberration, cross-sections in two additional two-rooted maxillary first molars were made. From these cross sections it can be concluded that the C-shaped canal configuration is the result of a fusion of the distobuccal and the palatal roots.     

上颌第二磨牙腭侧双根双根管1例

上颌第二磨牙根管系统变异较大,多为三根管,有时可见颊根融合,腭侧双根管较为罕见.报告1例较为罕见的上颌第二磨牙腭侧双根双根管病例,提示在接诊过程中,临床医师应对上颌第二磨牙的髓腔解剖形态做到心中有数,结合现代牙科辅助手段,做好根管治疗.     

Root and canal morphology of permanent mandibular molars in a Sri Lankan population

The main purpose of this study was to investigate the root and canal morphology of Sri Lankan mandibular molars and to determine the affinities of these morphological variations to those of people of European and Asian origin. Two hundred mandibular first and second molars were examined. The number of roots and the prevalence of C-shaped (gutter-shaped) roots in mandibular second molars were recorded. Root canal morphology was studied using a clearing technique. The examination of root canal systems of the teeth was based on Vertucci's classification. Among mandibular first molars, only 3% had three roots. Mesial roots of the first molar typically presented with two canals and two apical foramina with type IV, V, or VI canal configuration. Most distal roots of the first molar presented with a type I canal configuration. The remainder were distributed mainly between types III and V. Among mandibular second molars, 6% had single C-shaped roots, while C-shaped canals were found in only 2%. The majority of mesial roots of the second molar showed one or two canals, with one apical foramen with type I, II, or III canal morphology. In addition, the distal root commonly showed type I canal configuration. Intercanal communications and lateral canals were more frequently seen in the first molar than in the second. The root canal morphology in mandibular molars varies among population groups. Mandibular root and canal morphology of Sri Lankan people has closer affinities with that of people of European than of East Asian origin.     

C-shaped root canals of mandibular second molars in a Korean population: clinical observation and in vitro analysis

AIM: To investigate the incidence and morphology of C-shaped root canals of the mandibular second molar in a Korean population. METHODOLOGY: Through clinical observation, randomly selected 272 mandibular second molars of Korean patients were accessed and evaluated after taking radiographs for determination of working length. In an in vitro analysis, 96 extracted mandibular second molars of Korean patients were collected and embedded in resin using an Endodontic cube technique, and were sectioned at intervals of 1 mm. The specimens were then observed with a surgical microscope and were photographed. Canal configurations were assigned to one of three categories: Category I defined a C-shaped outline without any separation; Category II referred to those with canal configurations, where dentine separated one distinct canal from a buccal or lingual C-shaped canal; Category III had two or more discrete and separate canals. RESULTS: In clinical observation, 89 of 272 teeth (32.7%) had C-shaped canals. Of the 96 teeth examined in vitro, 30 (31.3%) had C-shaped canals. Upon in vitro analysis, only 1 tooth at the subpulpal level and 10 teeth at the apical 1 mm level were categorized under Category III. CONCLUSION: There was high prevalence of C-shaped root canals in the mandibular second molars of Koreans. C-shaped canals having semicolon and continuous shapes at the canal orifice have a high possibility of being divided into two or three canals in the apical region.     

右侧上颌第一磨牙腭侧双根管1例

上颌第一磨牙根管的解剖变异多发生于近颊根管,而腭根数目及腭侧根管数目的变异较少见。本文报道1例5个根管的右侧上颌第一磨牙,包括颊侧3个根管（近中根管2、远中根管1）和腭侧2个根管。医生在临床工作中应仔细进行髓腔内解剖结构的检查及X线片判读,必要时进行锥形束CT检查以防止遗漏根管。     

Root and canal morphology of permanent mandibular molars in a Sudanese population

AIM: To investigate variations in the root canal systems of first and second permanent mandibular molar teeth in a Sudanese population using a clearing technique. METHODOLOGY: Two hundred extracted first and second permanent mandibular molars from three cities in the state of Khartoum were studied. Access cavities were prepared and pulp tissue was removed by immersion in 5% sodium hypochlorite under ultrasonication; Indian ink was then injected into the root canal systems assisted by a vacuum applied apically. The teeth were rendered clear by demineralization and immersion in methyl salicylate before evaluation. The following observations were made (i) number of roots and their morphology; (ii) number of root canals per tooth; (iii) number of root canals per root and (iv) root canal configuration. RESULTS: Overall 59% of mandibular first molars had four canals with 3% having a third distolingual root. Seventy-eight per cent of second mandibular molars had two separate flat roots, whilst 10% were C-shaped. The most common canal system configurations were type IV (73%) and type II (14%). Inter-canal communications were more common in the mesial roots. The prevalence of inter-canal communications was 65% in first molars and 49% in second molars. CONCLUSIONS: In this sample of Sudanese teeth, 59% of the mandibular first permanent molars had four root canals whilst 10% of the mandibular second molars had C-shaped roots/canals.     

Incidence of canal systems in the mesio‐buccal roots of maxillary first and second molars in Saudi Arabian population

The aim of this prospective study was to determine the number of canals treated in the mesio‐buccal roots of the maxillary first and second molars teeth of a Saudi Arabian population during a 1‐year period in a postgraduate endodontic program. The attending endodontic faculty member supervising the case verified the number of canals in the teeth clinically and radiographically. In total, 308 maxillary first molars and 162 maxillary second molars, of which 158 (51.3%) and 32 (19.7%) met the criterion of having two canals detected and treated in the mesio‐buccal root of the maxillary first and second molars, respectively. It was concluded that the occurrence of mesio‐palatal canal in the mesio‐buccal root of the maxillary first and second molars of a Saudi Arabian population was high. The fact that almost more than half the mesio‐buccal roots of the maxillary first molars bear two canals is enough reason to always assume that two canals exist until careful examination proves otherwise.     

Evaluation of Root Canal Configuration of Maxillary Molars in a Brazilian Population Using Cone-beam Computed Tomographic Imaging: An In Vivo Study

Introduction

The aim of this study was to analyze and characterize root canal morphology of maxillary molars of the Brazilian population using cone-beam computed tomographic (CBCT) imaging.

Methods

Patients referred for a CBCT radiographic examination for accurate diagnosis and treatment planning were enrolled in the study. A total of 620 healthy, untreated, fully developed maxillary first and second molars were included (314 first molars and 306 second molars). The following observations were recorded: (1) number of roots and their morphology, (2) number of canals per root, (3) fused roots, and (4) primary variations in the morphology of the root canal systems.

Results

First and second molars showed a higher prevalence of 3 separate roots, mesiobuccal, distobuccal, and palatal, with 1 canal in each root (52.87% and 45.09%, respectively). Two canals in the mesiobuccal roots represented 42.63% of teeth, whereas mesiobuccal roots of second molars presented 2 canals in 34.32%. The most common anatomic variation in the maxillary first molar was related to the root canal configuration of the mesiobuccal root, whereas the root canal system of the maxillary second molar teeth showed more anatomic variables.

Conclusions

Mesiobuccal roots of maxillary molar teeth had more variation in their canal system than the distobuccal or palatal roots. The root canal configuration of the maxillary second molars was more variable than the first molars in a Brazilian population. CBCT imaging is a clinically useful tool for endodontic diagnosis and treatment planning.     

Root and root canal morphology of the human permanent maxillary first molar: a literature review

The objective of this study was to review the literature with respect to the root and canal systems in the maxillary first molar. Root anatomy studies were divided into laboratory studies (in vitro), clinical root canal system anatomy studies (in vivo) and clinical case reports of anomalies. Over 95% (95.9%) of maxillary first molars had three roots and 3.9% had two roots. The incidence of fusion of any two or three roots was approximately 5.2%. Conical and C-shaped roots and canals were rarely found (0.12%). This review contained the most data on the canal morphology of the mesiobuccal root with a total of 8399 teeth from 34 studies. The incidence of two canals in the mesiobuccal root was 56.8% and of one canal was 43.1% in a weighted average of all reported studies. The incidence of two canals in the mesiobuccal root was higher in laboratory studies (60.5%) compared to clinical studies (54.7%). Less variation was found in the distobuccal and palatal roots and the results were reported from fourteen studies consisting of 2576 teeth. One canal was found in the distobuccal root in 98.3% of teeth whereas the palatal root had one canal in over 99% of the teeth studied.     

Aberrant root canal morphology in a maxillary second molar

A bstract — Abberations in root canal morphology of maxillary permanent molars often occur as collateral mesio-buccal canals and, less commonly, as separate root canals in divergent palatal roots. This case report describes a right maxillary second molar with both types of anomaly common to the maxillary first molar and a collateral disto-palatal canal in a thirteen-year-old girl suffering severe pain in the right maxilla. Removal of discoloured dentine found beneath two amalgam restorations disclosed necrotic tissue in the pulp chamber and the disto-palatal canal. Finally, endodontic therapy was required for six root canals.     

Anatomical and histological features of C-shaped canals in mandibular second molars.

The mandibular second molar has many root canal variations. This investigation used two evaluation methods to examine the canal morphology of mandibular second molars having C-shaped canals. Fifteen extracted mandibular second molars with a conical root and C-shaped canal orifice were separated into two groups. A polyester cast resin technique allowed three-dimensional visualization of the root canal system in eight teeth; the remaining seven molars were prepared for histological examination in cross-section in the coronal, middle, and apical thirds for study under the light microscope. The results illustrated that C-shaped canals in mandibular second molars can vary in number and shape along the length of the root with the result that debridement, obturation, and restoration in this group may be unusually difficult.     

老年人下颌磨牙牙根及根管的锥形束CT研究

目的：利用锥形束CT观察分析老年人下颌磨牙的牙根、根管数目和形态。方法：选择能够配合检查,并在扫描过程中头部保持静止状况的老年人,对其牙齿进行锥形束CT扫描,对扫描图像进行三维重建和选择不同方向的断层观察记录下颌磨牙的牙根和根管。结果：锤形束CT检查老年人166例,下颌磨牙共532颗。下颌磨牙近中根均为单根,远中双根仅发生于下颌第一磨牙,而C形根则仅发生于第二磨牙。近中根以两根管为主在下颌第一磨牙和第二磨牙分别占有95．26％和50．38％;远中根以一根管为主在第一磨牙和第二磨牙分别占有64．60％和56．97％,C形根管的发生率为22．48％。结论：下颌磨牙牙根和根管的变化主要发生在第一磨牙的远中根和第二磨牙的C形根及C形根管。     

下颌第一恒磨牙C形根管2例

下颌第一恒磨牙根管系统复杂多样,其中C形根管较为少见。本文报道2种不同类型的下颌第一恒磨牙C形根管病例。病例1,一个完整C形融合牙根,根管特点为近中舌侧位置一个根管,C形态的峡部及远中位置融合为一个根管。病例2,颊侧一个C形态融合牙根和远中舌侧一个独立牙根,根管特点为颊侧C形态区域为Ⅱ-Ⅰ型根管和一个独立的远中舌侧根管。     

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.     

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。     

Root canal morphology of human maxillary and mandibular third molars

The anatomy of third molars has been described as unpredictable. However restorative, prosthetic, and orthodontic considerations often require endodontic treatment of third molars in order for them to be retained as functional components of the dental arch. The purpose of this study was to investigate and characterize the anatomy of maxillary and mandibular third molars. One hundred fifty maxillary and 150 mandibular extracted third molars were vacuum-injected with dye, decalcified, and made transparent. The anatomy of the root canal system was then recorded. Seventeen percent of mandibular molars had one root (40% of which contained two canals), 77% had two roots, 5% had three roots, and 1% had four roots. Teeth with two roots exhibited highly variable canal morphology, containing from one to six canals, including 2.2% that were "C-shaped." Fifteen percent of maxillary molars had one root, 32% had two roots, 45% had three roots, and 7% had four roots. Teeth with one root demonstrated the most unusual morphology, with the number of canals varying from one to six. An in vivo study of the canal morphology of treated third molars is suggested to provide the practitioner with an understanding of the clinical implications of third molar root anatomy.     

下颌第二磨牙根管显微镜下根管口分型探讨

目的通过显微镜分析下颌第二磨牙根管口的解剖特点及分型。方法选择患牙髓炎或根尖周炎的下颌第二磨牙653个,根管显微镜下观察并记录根管口形态,对其根管口形态分类计数,计算其出现率。结果下颌第二磨牙单根牙Ⅰ-1型47例(7.20%),Ⅰ-2型65例(9.95%),Ⅰ-3型263例(40.27%),Ⅰ-4型22例(3.37%);C形根管256例(39.21%)。完全C形根管及部分C形根管分别占17.31%、21.90%。结论根管显微镜下可以更好地观察下颌第二磨牙根管口形态,提高C形根管诊断率。根管口形态呈C形根管系统较多,不利于根管的彻底清理和充填。     

Root and canal morphology of mandibular first and second molar teeth in a Jordanian population

Aim  To examine the root and canal morphology of mandibular permanent first and second molar teeth in a Jordanian population.
Methodology  A total of 685 extracted mandibular first and second permanent molar teeth were collected from dental clinics within north Jordan. The teeth were examined visually and the root number and morphology were recorded. After that, access cavities were prepared, pulp tissue dissolved by sodium hypochlorite and the root canals injected with Indian ink. Stained teeth were decalcified with 10% nitric acid, dehydrated with ascending concentrations of alcohol and rendered clear by immersion in methyl salicylate. The following observations were evaluated: (i) number of canals per root; (ii) number of root canals per tooth; (iii) canal configuration in each root; (iv) number and location of lateral canals and (v) presence of intercanal communications.
Results  Of 330 mandibular first molars, the majority had three (48%) or four (46%) canals, whilst 4% had a third disto-lingual root. Of 355 mandibular second molars, 58% had three canals, 19% two and 17% had four canals, whilst 10% had C-shaped roots. The most prevalent canal configuration in the mesial root of both first (53%) and second (40%) molars was type IV, and in distal roots was type I (54% in first and 79% in second molars).
Conclusions  Jordanian mandibular first and second molar teeth exhibit features close to the average Caucasian root and canal morphology.