Root canal morphology and root variation of the mandibular first premolar: A study by cone-beam computed tomography / 医学研究生学报

ABSTRACT

Objective Few studies are reported on the radicular groove and root canal variation of the mandibular first premolar.This study aimed to observe the root canal system and root variation of the mandibular first premolar by cone-beam computed tomography (CBCT).Methods We selected CBCT images of 643 mandibular first premolars of 336 patients and subjected the data obtained to statistical analysis.Results Of the 643 mandibular first premolars, 637 (99.1％) had a single root and the other 6 had double roots;502 (78.1％) had a single root canal, 133 (20.7％) had two, 5 (0.78％) had three, and 3 (0.47％) presented C-shaped root canal morphology.The average length of the 643 mandibular first premolars was (13.2±1.5) mm and the mean distance from the apical foramen to the anatomical apical end of the root was (0.93±0.35) mm.Totally, 123 (19.1％) of the mandibular first premolars had a radicular groove, of which 94 (76.4％) had double root canals and the root canal systems included typesⅠ in 24 (19.5％), Ⅱ in 2 (1.6％), Ⅲ in 19 (15.4％), Ⅳ in 1 (0.8％), Ⅴ in 69 (56.1％), and Ⅶ in 3 (2.4％).Conclusion The root canal system of the mandibular first premolar has a significant variation.CBCT can reveal the complex anatomical structure of the mandibular first premolar and provide reliable evidence for the root canal treatment.