• Restorative Dentistry and Endodontics
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• v.44 no.2
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• pp.16.1-16.12
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• 2019

Objectives: The upper molars generally have three roots; therefore, different combinations of fusion can occur, increasing the possibility of finding more complex root canal systems. The purpose of this study was to evaluate the prevalence and characterization of fused roots in first and second maxillary molars using cone-beam computed tomography (CBCT) in a Colombian population. Materials and Methods: A total of 1274 teeth were evaluated, of which 534 were maxillary first molars and 740 were maxillary second molars. Axial sections were made at the cervical, middle, and apical levels to determine the prevalence of root fusion and the types of fusion. Results: Overall, 43% of the molars (n = 551) presented some type of fused root. Root fusion was present in 23.4% of the maxillary first molars. The most frequent type of fused root was type 3 (distobuccal-palatal; DB-P) (58.9%). Root fusion was observed in 57.6% of the maxillary second molars, and the most prevalent type of fused root was type 6 (cone-shaped) (45.2%). Of the maxillary molars, 12.5% were classified as C-shaped. Conclusion: Within the limitations of this study, there was a high prevalence of fused roots in maxillary molars in the Colombian population, mainly in the maxillary second molars. In first molars, the most common type of fused root was type 3 (DB-P) and in second molars, the most common type was type 6 (cone-shaped). Additionally, molars with root fusion presented variation at different levels of the radicular portion, with implications for treatment quality.

• Imaging Science in Dentistry
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• v.45 no.2
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• pp.95-101
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• 2015

Purpose: This study used cone-beam computed tomography (CBCT) to characterize mandibular molar root and canal morphology and its variability in Belgian and Chilean population samples. Materials and Methods: We analyzed the CBCT images of 515 mandibular molars (257 from Belgium and 258 from Chile). Molars meeting the inclusion criteria were analyzed to determine (1) the number of roots; (2) the root canal configuration; (3) the presence of a curved canal in the cross-sectional image of the distal root in the mandibular first molar and (4) the presence of a C-shaped canal in the second mandibular molar. A descriptive analysis was performed. The association between national origin and the presence of a curved or C-shaped canal was evaluated using the chi-squared test. Results: The most common configurations in the mesial root of both molars were type V and type III. In the distal root, type I canal configuration was the most common. Curvature in the cross-sectional image was found in 25% of the distal canals of the mandibular first molars in the Belgian population, compared to 11% in the Chilean population. The prevalence of C-shaped canals was 10% or less in both populations. Conclusion: In cases of unclear or complex root and canal morphology in the mandibular molars, CBCT imaging might assist endodontic specialists in making an accurate diagnosis and in treatment planning.

• Journal of Dental Rehabilitation and Applied Science
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• v.30 no.4
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• pp.324-328
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• 2014

Aberrant anatomy of mandibular premolars is very rare in Korean, but aberration can contribute the endodontic failure as it makes difficult to remove the irritants during cleaning and shaping procedure. This case report describes the successful root canal treatment of a rare mandibular first premolar with C-shaped root canal as using a cone-beam computed tomography to understand the internal shape of root canal system and a dental operating microscope to improve the magnification and illumination.

• The Journal of the Korean dental association
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• v.37 no.6 s.361
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• pp.456-460
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• 1999

• Restorative Dentistry and Endodontics
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• v.49 no.1
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• pp.2.1-2.12
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• 2024

Objectives: This study aimed to determine the effects of 1-rooted mandibular second molar (MnSM) teeth on root canal anatomy complexities of the mandibular central incisor (MnCI), mandibular lateral incisor (MnLI), mandibular canine (MnCn), mandibular first premolar (MnFP), mandibular second premolar (MnSP), and mandibular first molar (MnFM) teeth. Materials and Methods: Cone-beam computed tomography images of 600 patients with full lower dentition were examined. Individuals with 1-rooted MnSMs were determined, and the complexity of root canal anatomy of other teeth was compared with individuals without 1-rooted MnSMs (Group-1; subjects with at least one 1-rooted MnSM, Group-2; subjects with more than a single root in both MnSMs). A second canal in MnCIs, MnLIs, MnCns, MnFPs, and MnSPs indicated a complicated root canal. The presence of a third root in MnFMs was recorded as complicated. Results: The prevalence of 1-rooted MnSMs was 12.2%, with the C-shaped root type being the most prevalent (9%). There were fewer complicated root canals in MnCIs (p = 0.02), MnLIs (p < 0.001), and MnFPs (p < 0.001) in Group 1. The other teeth showed no difference between the groups (p > 0.05). According to logistic regression analysis, 1-rooted right MnSMs had a negative effect on having complex canal systems of MnLIs and MnFPs. Left MnSMs were explanatory variables on left MnLIs and both MnFPs. Conclusions: In individuals with single-rooted MnSMs, a less complicated root canal system was observed in all teeth except the MnFMs.

• Restorative Dentistry and Endodontics
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• v.41 no.3
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• pp.182-188
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• 2016

Objectives: The purpose of this study was to evaluate the proximity of the mandibular molar apex to the buccal bone surface in order to provide anatomic information for apical surgery. Materials and Methods: Cone-beam computed tomography (CBCT) images of 127 mandibular first molars and 153 mandibular second molars were analyzed from 160 patients' records. The distance was measured from the buccal bone surface to the root apex and the apical 3.0 mm on the cross-sectional view of CBCT. Results: The second molar apex and apical 3 mm were located significantly deeper relative to the buccal bone surface compared with the first molar (p < 0.01). For the mandibular second molars, the distance from the buccal bone surface to the root apex was significantly shorter in patients over 70 years of age (p < 0.05). Furthermore, this distance was significantly shorter when the first molar was missing compared to nonmissing cases (p < 0.05). For the mandibular first molars, the distance to the distal root apex of one distal-rooted tooth was significantly greater than the distance to the disto-buccal root apex (p < 0.01). In mandibular second molar, the distance to the apex of C-shaped roots was significantly greater than the distance to the mesial root apex of non-C-shaped roots (p < 0.01). Conclusions: For apical surgery in mandibular molars, the distance from the buccal bone surface to the apex and apical 3 mm is significantly affected by the location, patient age, an adjacent missing anterior tooth, and root configuration.

• Imaging Science in Dentistry
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• v.45 no.4
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• pp.221-226
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• 2015

Purpose: This study evaluated the prevalence of distolingual roots in mandibular molars among Koreans, the root canal system associated with distolingual roots, and the concurrent appearance of a distolingual root in the mandibular first molar and a C-shaped canal in the mandibular second molar. Materials and Methods: Cone-beam computed tomographic images of 264 patients were screened and examined. Axial sections of 1056 mandibular molars were evaluated to determine the number of roots. The interorifice distances from the distolingual canal to the distobuccal canal were also estimated. Using an image analysis program, the root canal curvature was calculated. Pearson's chi-square test, the paired t-test, one-way analysis of variance, and post-hoc analysis were performed. Results: Distolingual roots were observed in 26.1% of the subjects. In cases where a distolingual root was observed in the mandibular molar, a significant difference was observed in the root canal curvature between the buccolingual and mesiodistal orientations. The maximum root canal curvature was most commonly observed in the mesiodistal orientation in the coronal portion, but in the apical portion, maximum root canal curvature was most often observed in the buccolingual orientation. Conclusion: The canal curvature of distolingual roots was found to be very complex, with a different direction in each portion. No correlation was found between the presence of a distolingual root in the mandibular first molar and the presence of a C-shaped canal in the mandibular second molar.

• Restorative Dentistry and Endodontics
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• v.34 no.4
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• pp.346-349
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• 2009

Mandibular second molars have many variations in canal configuration. Technical modifications in cleaning, shaping and obturation are required. The purpose of this study was to investigate the root canal anatomy of mandibular second molars. 86 teeth of 85 patients were accessed and evaluated with taking radiographs for working length determination. 27 teeth(31.4%) had C-shaped canals, 43 teeth(50%) had 3 canals, 11 teeth(12.7%) had 4 canals, 5 teeth(5.8%) had 2 canals. Incidence of C-shaped canal was 31.7% in male and 31.1% in female. 30.9% of left mandibular second molar and 31.8% of right mandibular second molar showed C-shaped canals.

• The Journal of the Korean dental association
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• v.40 no.7 s.398
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• pp.542-547
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• 2002

This study was aimed to help diagnose the vertical root fractures in endodontically and in nonendodontically treated teeth. This was a study about mine teeth with a vertical root fractures. Four cases were nonendodontically treated teeth and five cases were endodontically treated teeth. A collection of information including past dental history, periodontal probing, and X-ray was gathered on each case. One of the endodontic cases had no periodontal pocket depth and was in acute pain. It was confusing to find whether causes were because of endodontic failure or vertical root fractures. Most of the vertical root fractures were found in patients aged between 50 and 60. Vertical root fractures were found in the molar and premolar of maxillary and mandibular teeth. The second molars repecially, which had C shaped roots had vertical root fractures with apical propagation type. The apical propagation type means that vertical root fracture initiates in root apex and propagate to coronal root. The teeth with vertical root fractures of the apical propagation type, which was in acute pain, were very difficult in differential diagnosis of periodontal lesion and endodontic failure. Therefore, the dental history was very important to make a differential diagnosis. Past pain history repeated uncomfortable symptoms in bite was a key of differential diagnosis.

• Restorative Dentistry and Endodontics
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• v.22 no.2
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• pp.731-738
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• 1997

A retrospective in vivo study of endodontically treated mandiblar molars was conducted. The radilographs and clinical records of mandibular molars that had been treated endodontically in the Dental hospital of Yonsei University from 1986 to July 1997 were reviewed and categorized. A total of 1751 cases were studied and following results were obtained. 1. The number of root canals in mandibular first permanent molar in a Korean population revealed three in 53.2 %, four in 23.0 %, two in 18.4 %, C-shaped canal in 5.0 %, and one in 0.4 %. 2. In mandibular second molar, three canals was observed in 53.2 %, four in 22.2 %, two in 14.9%, C-shaped canal in 9.1 %, and one in 0.6%. 3. In the results of the percentage of 4 canals of mandibular first molars at various age, before age 20, 37.7 % was obtained whereas 19.3 % after 30. 4. 7.94 % of mandibular first molars examined were found to have three roots. 5. The mandibular second molar had C-shaped canals in 9.1 %.