Analysis of the Location, Angle, Radius, and Direction of Curvature in Maxillary Lateral Incisor Roots Using CBCT, in an Iranian Population

Introduction: The risk of error is higher in the treatment of teeth with curved roots, resulting in the reduced success of root canal treatment. Maxillary lateral incisors are more likely to curve in the buccolingual direction. In this study, we aimed to evaluate the curvature of maxillary lateral incisors, using cone-beam computed tomography (CBCT). Methods: This descriptive, analytical study was performed on 117 patients, with an average age of 40 years, who were referred to a private radiology center. The curvature angle was measured using the Schneider method, and the curvature radius was determined using the Estrela method. Moreover, the distance between the starting point of the curvature and the cementoenamel junction (CEJ) was measured using Planmeca Romexis Viewer 2.9.2.R and Geometry Expressions v. 3.0. The collected data were analyzed using SPSS 17. Findings: The degree of curvature was classified according to the Seidberg classification. In the coronal view, the curvature degree was mild to moderate; further, severe curvature was quite common (left, 31.2% vs. right, 22.9%). In the sagittal view, the curvature degree was mostly mild, and severe curvature was rarely observed (left, 1% vs. right, 1.8%). The curvature radius was mild in most cases, and most curvatures were distally inclined. The mean distance from the starting point of the curvature to the CEJ was 10.5 mm on the left and 10.2 mm on the right. Conclusion: The results indicated a mild to moderate degree of curvature in the root. There was a significant positive correlation between the curvature angle in the coronal view and curvature angle in the sagittal view on both sides.