Imaging Sci Dent.  2015 Jun;45(2):95-101. 10.5624/isd.2015.45.2.95.

Characterization of mandibular molar root and canal morphology using cone beam computed tomography and its variability in Belgian and Chilean population samples

• Torres A
• Jacobs R
• Lambrechts P
• Brizuela C
• Cabrera C
• Concha G
• Pedemonte

• KMID: 2054211
• DOI: http://doi.org/10.5624/isd.2015.45.2.95

Abstract

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.

Keyword

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

MeSH Terms

Belgium
Cone-Beam Computed Tomography*
Dental Pulp Cavity
Diagnosis
Molar*
Prevalence
Specialization

Figure

• 

  Fig. 1 Classification of root canal configuration.1 Type I: a single canal extends from the pulp chamber to the apex. Type II: two separate canals leave the pulp chamber and join short of the apex to form one canal. Type III: one canal leaves the pulp chamber, divides into two within the root, and then merges to exit as one canal. Type IV: Two separate and distinct canals extend from the pulp chamber to the apex. Type V: one canal leaves the pulp chamber and divides short of the apex into two separate and distinct canals with separate apical foramina. Type VI: two separate canals leave the pulp chamber, merge in the body of the root, and re-divide short of the apex to exit as two distinct canals. Type VII: one canal leaves the pulp chamber, divides and then rejoins within the body of the root, and finally re-divides into two distinct canals short of the apex. Type VIII: three separate and distinct canals extend from the pulp chamber to the apex.

• 

  Fig. 2 Curved canal in the cross-sectional image of the distal root in the mandibular first molar. A. Left: a mandibular first molar with (M) mesial and (D) distal roots. Right: cross-sectional image of a mandibular first molar as seen in an axial-plane CBCT view. (M) mesial root, (D) distal root, (*), cortical and trabecular bone structure. When a straight line is drawn in the distal ribbon-shaped canal, it only comes in contact with the (a) buccal and (b) lingual ends of the canal. B. Cone-beam computed tomography cross-sectional images. 1a-c: curved distal canals in cross-sectional images, 1d: an oval canal, 2a and b: curved distal canals in cross-sectional images, 2c: a canal starting to divide, 2d: a fully divided canal, 3a-d: the absence of a curved distal canal in cross-sectional images.

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  Fig. 3 Classification of C-shaped canal configurations.19 A. C1: an uninterrupted "C" with no separation or division, C2: a canal shape resembling a semi-column resulting from the discontinuation of the "C" outline, C3: three (a) or two (b) separate canals, C4: only one round or oval canal in the cross-sectional image, C5: no observable canal lumen (usually only found near the apex). B. Cross-sectional CBCT images of different types of C-shaped canal configurations, at different root levels.

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