Evaluation of root and canal morphology of mandibular premolar amongst Saudi subpopulation using the new system of classification: a CBCT study

Abstract
Background The clinician should have complete knowledge of the normal anatomy of the root as well as
complexities in the root canal configuration for a better outcome, as missed or improper handling of the canal system
can lead to the failure of an entire endodontic procedure. The present study aims to assess the morphology of roots
and canals in permanent mandibular premolars in the Saudi subpopulation with a new classification system.
Methods The present study includes 1230 mandibular premolars (645 first premolars and 585-second premolars)
from 500 CBCT images of the patients, including retrospective data. iCAT scanner system (Imaging Sciences
International, Hatfield, PA, USA) was used to obtain the images; scanning of 8 × 8 cm images was performed at 120
KVp and 5–7 mA with a voxel size of 0.2 mm. The new method of classification presented by Ahmed et al. 2017 was
used to record and classify the root canal morphology, followed by recording the differences regarding the age and
gender of the patients. Comparison of canal morphology in lower permanent premolars and its association with
gender and age of the patients was done by Chi-square test/ Fisher exact test; the significance level was set at 5%
(p ≤ 0.05).
Results The left mandibular 1st and 2nd premolars with one root were 47.31%, with two roots were 2.19%. However,
three roots (0.24%) and C-shaped canals (0.24%) were reported only in the left mandibular 2nd premolar. The right
mandibular 1st and 2nd premolars with one root were 47.56%, with two roots were 2.03%. The overall percentage
of the number of roots and canals in the first and second premolars 1 PM 1 (88.38%), 2 PM 1 B 1
L 1 (3.5%), 2 PM B 1
L
1 (0.65%), 1 PM 1–2−1 (3.08%), 1 PM 1–2 (3.17%), 1 PM 1–2−1–2 (0.24%), 3 PMMB 1 DB 1 L1 (0.48%). However, the C-shaped
canals (0.40%) were reported in right and left mandibular second premolars. No statistically significant difference
was reported between mandibular premolars and gender. A statistically significant difference was reported between
mandibular premolars and the age of the study subjects.