Imaging Sci Dent.  2015 Dec;45(4):221-226. 10.5624/isd.2015.45.4.221.

Prevalence and features of distolingual roots in mandibular molars analyzed by cone-beam computed tomography

• Choi MR
• Moon YM
• Seo MS

• KMID: 2132934
• DOI: http://doi.org/10.5624/isd.2015.45.4.221

Abstract

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.

Keyword

Cone-Beam Computed Tomography; Molar; Mandible; Dental Pulp Cavity

MeSH Terms

Cone-Beam Computed Tomography*
Dental Pulp Cavity
Humans
Mandible
Molar*
Prevalence*

Figure

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  Fig. 1 Mandibular molars with a distolingual root visible in the axial section. A. Bilateral occurrence, B. Unilateral occurrence.

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  Fig. 2 A. Cone-beam computed tomographic images are displayed in three planes. The software automatically displays the locations of the designated points using three-dimensional coordinates (x, y, and z). B. The schema for the current study design. Red arrows indicate the distolingual roots of the mandibular molars. The centers of the root canals are plotted manually, and individual points are connected to create curves.

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  Fig. 3 Mandibular molars with the concurrent presence of a distolingual root and a C-shaped canal. A. Bilateral occurrence, B. Unilateral occurrence.

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