Cone-beam computed tomography study of C-shaped root canal of mandibular premolars / 口腔疾病防治

ABSTRACT

Objective@#To investigate the incidence and morphology of C-shaped root canals in mandibular premolars by cone-beam computed tomography (CBCT) imaging, which provides a reference for clinical diagnosis and treatment.@*Methods @#The CBCT scanning data of 964 mandibular first premolars and 907 mandibular second premolars in 508 cases were collected, and the root canal morphology, incidence of C-shaped root canals, bilateral symmetry and location of radicular grooves were analyzed.@*Results@#The incidence of C-shaped root canals in mandibular first premolars was 4.1% and that in mandibular second premolars was 0.6%. The incidence of C-shaped root canals of mandibular first premolars was significantly higher than that of mandibular second premolars (χ2=25.775, P < 0.001). The symmetrical ratio of C-shaped root canals in the mandibular first premolars was 29%. There were no symmetrical C-shaped root canals in the mandibular second premolars. There were significant differences in the distribution of the C-shaped root canal configuration in the root canal (P < 0.001). The C-shaped configuration mainly existed in the middle axial and apical level of the mandibular premolars. The C2 type was more common. No C-shape was found in the coronal level of the mandibular premolars. Vertucci I single tube type was the most common type of root canal for the mandibular premolars included in this study; the incidences were 81.7% and 98.3% for the mandibular first and second premolars, respectively, and the difference was statistically significant (χ2=140.544, P < 0.001). The other root canal types of mandibular first premolars were more than those of mandibular second premolars. The incidences of Vertucci Ⅱ, Ⅲ, Ⅳ, and Ⅴ and C-shaped root canals in mandibular first premolars were significantly higher than those in mandibular second premolars. C-shaped root canal mandibular premolars had radicular grooves, and most of them were located at the mesiolingual side.@*Conclusion@# The morphology of the C-shaped root canal in mandibular premolars was complicated. CBCT can provide direct and accurate imaging evidence for clinical diagnosis and treatment.