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.     

上颌第一磨牙根管系统的研究

目的 观察上颌第一磨牙的根管系统。方法 制备50个上颌第一磨牙透明牙标本,显露根管系统的空间构型,在体视显微镜下观察并记录根管系统的形态,结合应用加以统计。结果 ①上颌第一磨牙近中颊根单根管率为66%,其中Ⅰ型占38%,双根管率为34%,远中颊根Ⅰ型占74%,腭根Ⅰ型占94%。②根管侧支、根尖分歧、根尖分叉多见于近颊根,在近颊根的发生率为40%, 远颊根的发生率为24%,腭根的发生率为6%,发生部位多见于根尖1/3。结论 上颌第一磨牙近颊根的根管系统最为复杂,根管变异较远颊根多,腭根变异最少。     

Root canal morphology of the mesiobuccal root in maxillary first molars of a Jordanian population

This in vitro study investigated the presence of second (MB2) root canals and the number of apical foramina found in mesiobuccal roots of the permanent maxillary first molars; in addition, the study evaluated the effectiveness of magnification to detect MB2 canals. One hundred extracted maxillary first molars were collected from Jordanian patients. The number of roots (as well as their morphology) was investigated. The number of canal orifices in mesiobuccal root was assessed, with and without magnification, and findings were compared. The number of apical foramina and the distance between mesiobuccal and second canal orifices were investigated under magnification. Of the 97 specimens that were subject to additional investigation, all teeth had three separated roots, except for three specimens that had either mesiobuccal or distobuccal roots fused with the palatal root. The number of MB2 canals that were detected increased from 55 (56.7%) to 61 (62.9%) teeth when magnification was used. Within the limits of this in vitro study, it was concluded that the Jordanian population had a high percentage of MB2 canals in the mesial buccal roots. Moreover, the use of clinically used magnifying devices increased the number of MB2 canals detected.     

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.     

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.     

A study of the distobuccal root canal orifice of the maxillary second molars in Chinese individuals evaluated by cone-beam computed tomography

As is commonly understood, the root canal morphology of the maxillary molars is usually complex and variable. It is sometimes difficult to detect the distobuccal root canal orifice of a maxillary second molar with root canal treatment. No literature related to the distobuccal root canals of the maxillary second molars has been published.

Objective

To investigate the position of the distobuccal root canal orifice of the maxillary second molars in a Chinese population using cone-beam computed tomography (CBCT).

Material and methods

In total, 816 maxillary second molars from 408 patients were selected from a Chinese population and scanned using CBCT. The following information was recorded: (1) the number of root canals per tooth, (2) the distance between the mesiobuccal and distobuccal root canal orifice (DM), (3) the distance between the palatal and distobuccal root canal orifice (DP), (4) the angle formed by the mesiobuccal, distobuccal and palatal root canal orifices (∠ PDM). DM, DP and ∠ PDM of the teeth with three or four root canals were analyzed and evaluated.

Results

In total, 763 (93.51%) of 816 maxillary second molars had three or four root canals. The distance between the mesiobuccal and distobuccal orifice was 0.7 to 4.8 mm. 621 (81.39%) of 763 teeth were distributed within 1.5-3.0 mm. The distance between the palatal and distobuccal orifice ranged from 0.8 mm to 6.7 mm; 585 (76.67%) and were distributed within 3.0-5.0 mm. The angle (∠ PDM) ranged from 69. 4º to 174.7º in 708 samples (92.80%), the angle ranged from 90º to 140º.

Conclusions

The position of the distobuccal root canal orifice of the maxillary second molars with 3 or 4 root canals in a Chinese population was complex and variable. Clinicians should have a thorough knowledge of the anatomy of the maxillary second molars.     

Root and canal morphology of Thai maxillary molars

AIM: To investigate the root and canal morphology of 268 maxillary permanent molars collected from an indigenous Thai population. METHODOLOGY: The cleaned teeth were accessed, the pulp dissolved by sodium hypochlorite under ultrasonication, and the pulp system injected with Indian ink. The teeth were rendered clear by demineralization and immersion in methyl salicylate. The following observations were made: (i) number of roots and their morphology; (ii) number of root canals per root; (iii) root-canal configuration in each root using Vertucci's classification with additional modifications; and (iv) presence and location of lateral canals and intercanal communications. RESULTS: All the maxillary first and second molars had three separate roots. Only, half (51%) of the maxillary third molars had three separate roots; the other half had fused or conical roots. The majority of the distobuccal (98.1-100%) and palatal (100%) roots had type I canals. Over half of the mesiobuccal roots of first (65%) and second (55%) molars had two canals. The most common (44.2%) canal configuration in mesiobuccal roots of first molars was type IV (two canals, two foramina). A variety of canal types were found in the mesiobuccal roots of second molars. Maxillary third molars showed the greatest diversity of canal morphology. There was an increase in the prevalence of lateral canals towards the apical part of the roots and intercanal communications were present in 16% of each of first, second and third Thai maxillary molars. CONCLUSIONS: The mesiobuccal roots of Thai maxillary molars possessed a variety of canal system types. Over 50% of the first molars had a second mesiobuccal canal. The palatal and distobuccal canals mainly had type I canals. Only, a small proportion (7.3-13.3%) of the roots exhibited lateral canals which were the most common in the apical third     

山东地区人离体上颌第二恒磨牙牙根及根管形态观察

目的:观察山东地区人上颌第二恒磨牙牙根及根管形态的解剖特点。方法:于山东地区收集离体上颌第二恒磨牙118个,观察牙根形态及类型;应用透明牙标本法观察根管形态并按Vertucci八分类法对其进行分类。结果:118个上颌第二恒磨牙中以3根分离者为主,占91.52%,牙根融合者共10例,占8.47%,其中融合成2根者为5.08%,主要为近中颊根与远中颊根融合;融合成单根者为3.39%。透明牙标本法下观察根管系统,上颌第二恒磨牙远中颊根及腭根根管以Ⅰ型为主;近颊根根管仅44.95%为Ⅰ型,近颊根第二根管(the second mesiobuccal canal,MB2)的发生率达51.38%。结论:山东地区上颌第二恒磨牙的牙根具有多样性,以3根分离根形态为主,同时可发生各种融合根;其根管形态复杂,MB2的发现率较高。     

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.     

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。     

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。     

C-shaped root canal in a maxillary first molar: a case report

AIM: This case report presents an unusual C-shaped root canal system in a maxillary first molar tooth. SUMMARY: Although C-shaped root canals are most frequently seen in the mandibular second molar, they may also appear in maxillary molars. A literature search revealed only a few case reports of C-shaped root canal systems in maxillary molars. The present case describes a C-shaped canal in the buccal root of a maxillary first molar. The endodontic access cavity displayed two canal orifices, one leading to the canal system in the buccal root, the other into the palatal root canal system. In the buccal root, what appeared to be the mesial and distal canals joined to form a single C-shaped canal. KEY LEARNING POINTS:--Careful examination of radiographs and the internal anatomy of teeth is essential.-- The location and morphology of root canals should be identified at high magnification under the microscope.     

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.     

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.     

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.     

上颌第二磨牙近颊融合根中MB2的锥束CT研究

目的:通过锥束CT技术研究上颌第二磨牙近颊融合根中MB2的发生率。方法:收集199例患者的上颌第二磨牙CBCT数据,观察牙根融合类型、年龄以及牙位对MB2发生的影响。结果:199例患者共有380颗上颌第二磨牙,其中145颗牙的近中颊根与其他牙根融合;近远中颊根融合型(Ⅰ型)和近中颊根腭根融合型(Ⅱ型)的MB2发生率分别是5.5%、41.9%,而全融合型(Ⅲ型)则未发现MB2,Ⅰ、Ⅲ型融合的MB2发生率低于Ⅱ型;随着年龄增大,MB2发生率降低;181例具有双侧上颌第二磨牙的患者中,左右两侧融合根及MB2的发生率无显著差异。结论:上颌第二磨牙近中颊根与其他牙根融合时,其MB2发生率会出现变异。     

Root and Root Canal Morphology in Maxillary Second Molar with Fused Root from a Native Chinese Population

Introduction

Root fusion is an anatomic variation in maxillary second molars (MSMs); however, the nature of this canal morphology as it relates to its root anatomy has not been fully clarified. The purpose of this study was to investigate the relationship between features of fused roots and root canal anatomy in MSMs using micro–computed tomographic imaging.

Methods

One hundred eighty-seven extracted MSMs were scanned with the μCT50 (Scanco Medical, Bassersdorf, Switzerland), and their root and canal morphology was classified and analyzed using the classifications proposed by Yang and Vertucci. The number and position of canals that merged were recorded and compared among different root fusion types.

Results

One hundred eight (57.75%) MSMs had 3 separate roots, and 79 (42.25%) had fused roots. Of the 79 fused roots, 22 showed partial canal merging, and 6 had complete canal merging. Canal merging was found with teeth with 3-root fusion more often than in those with 2-root fusion (P < .05). Of 28 merged canals, 16 occurred between mesiobuccal and distobuccal canals and 9 among mesiobuccal, distobuccal, and palatal canals.

Conclusions

MSMs with fused roots may present a complicated root canal system as a result of canal merging.     

上颌第一磨牙远颊双根管1例

上颌第一磨牙根管系统复杂多样,近颊根双根管发生率较高,而远颊根少有双根管报道。本文报道1例具有5根管的上颌第一磨牙（其中近颊及远颊根各2个根管）。     

Three Root Canals in the Mesiobuccal Root of Maxillary Molars: Case Reports and Literature Review

Introduction

The knowledge of root canal anatomy is essential to ensure a successful outcome of surgical and nonsurgical root canal treatment. The aims of this article were to present 2 cases of maxillary molars with 3 mesiobuccal root canals and to review the available literature on this anatomic variation.

Methods

The first case described a nonsurgical root canal treatment of tooth #16 in a 29-year-old man with the aid of a dental operating microscope. In the second case, an extracted maxillary right first molar was scanned by a micro–computed tomographic system and reconstructed 3-dimensionally using modeling software.

Results

In both cases, the mesiobuccal root had 3 canals (type 3-2 in case I and type 3-3 in case II), whereas the distobuccal and palatal roots had a single canal. The literature review showed that the overall incidence of 3-canaled mesiobuccal roots in maxillary molars ranged from 1.3%–2.4% and that the most common root canal configuration was type 3-2.

Conclusions

Clinicians should always anticipate the presence of extra canals in maxillary molars and use all the available tools to locate and treat these.     

Root and canal morphology of the mesiobuccal and distal roots of permanent first molars in a Kuwait population--a clinical study

Aim To identify the number of roots and canal configurations in permanent first molars of the indigenous Kuwaiti sub‐population and compare them against a similar group of non‐Kuwaiti population in different age groups and gender, and to determine the frequency of a second canal in the mesiobuccal root of maxillary first molars and distal root of mandibular first molars that could be located and treated in routine practice without using magnification or special lighting conditions. Methodology A total of 220 permanent first molar teeth of patients scheduled for root canal treatment over a period of 1 year were included. Patients were identified and grouped according to their nationality as Kuwaiti and non‐Kuwaiti (which included Filipinos, Indonesian Indians, Srilankans, Egyptians, Saudi Arabians and Syrians). In both nationality groups, patients were successively distributed into four groups based on their age. The first age group included patients below 20 years, the second 21–30 years, the third 31–40 years and the fourth were over 40 years. The first three groups comprised of 15 male and 15 female patients whilst the fourth group had 10 patients of each gender. Teeth with open apices, resorptions and calcification were excluded from the study. The teeth included were both clinically and radiographically examined for number of roots, the canal configuration and the presence of the additional mesiobuccal and distal canals and recorded. The simplified classification of canal configurations proposed by Weine was utilized. Results The incidence of a second canal in the mesiobuccal (MB) root of maxillary first molars and the distal root of mandibular first molars was not influenced significantly by nationality and gender. All the 110 maxillary first molars treated had three roots; 58% of MB root had one canal and 42% had two canals. The majority of the mesial roots had Weine type II canal configuration when the second mesiobuccal canal was present. All distobuccal and palatal roots had a single or type I canal configuration. Of the 110 mandibular first molars that were treated, 96% had two roots and 4% had three roots. When present, the third root was located either buccal or lingual to the main distal root. Overall 51% of the single distal roots had one canal whilst 49% had two canals. The mesial root frequently had a Weine type II canal configuration as did the distal root when a second canal was present. Pearson’s correlation analysis of both molars revealed a significant (P < 0.05) negative correlation (r = ?0.274, r = ?0.144) between age and number of canals as well as the type of canal. Conclusions The incidence of a second canal in distal roots of permanent mandibular first molars was 49% in the Kuwaiti population and this was similar to other Asian ethnic populations. Adopting modified access and troughing procedures revealed a 42% frequency of MB2 canals in maxillary first molars. The incidence of a second canal in both mesiobuccal roots of maxillary molars and distal roots of mandibular molars decreased significantly with age; no differences were noticed amongst the nationalities and gender studied. The possibility of extra roots should be anticipated in mandibular molars.