Background: Cone-Beam Computed Tomography (CBCT) provides a better diagnosis
of endodontic lesions.
Introduction: The present study would assess the pattern of periapical lesion extension in premolar
teeth using CBCT.
Methods: In this descriptive study‚ 330 roots in the regions of maxillary and mandibular premolars
have been evaluated. Maximum periapical lesion extensions in the three orthogonal planes (axial,
coronal, and sagittal) were measured and recorded in millimeters. Measurements were compared
based on gender‚ dental arch, tooth type, and root. Statistical analysis was performed using repeated
measure ANOVA, Bonferroni, Chi-square tests, and clustering data analysis (K-means method).
The significant level was set at 0.05.
Results: There were significant differences between the lesion expansions in the three-dimensional
planes (p-value<0.001). The highest average of lesion extension in the premolar regions of the examined
population was reported in the vertical dimension (4.1± 1.3), followed by horizontal buccolingual
dimension (3.4±1.1) and horizontal mesiodistal dimension (3.1±1.0), respectively. According
to independent variables, in the premolar region, only tooth roots showed significant differences
in the lesion extension (p-value=0.002). Clustering data analysis showed that the majority of
the participants were categorized in a cluster with lower lesion extension. Based on clustering data
analysis, the small lesions were significantly observed in the first premolar and buccal roots.
Conclusion: Since the periapical lesion extension in the buccolingual dimension, which could not
be detected in the 2-D imaging techniques, was rather high in the region of premolar teeth, and
CBCT, as a 3-D imaging technique, is a suitable option for the precise evaluation of periapical lesion
extension. Also, the majority of the lesions in this tooth area are small and located in the buccal