Evaluation of Apical Root Morphology of Maxillary Incisors using Cone Beam Computed Tomography in Brazilian Subpopulation: A Cross-sectional Study

Abstract

Introduction: The prevalence of Apical Root Resorption (ARR) after orthodontic treatment is high. It is associated with several factors, such as tooth group, type and duration of treatment, applied force and root morphology. Aim: To evaluate the apical root morphology of maxillary incisors in a Brazilian subpopulation using Cone Beam Computed Tomography (CBCT) images. Materials and Methods: In this retrospective and cross-sectional study, 400 maxillary incisors from 167 patients registered in the data base of Dental Radiology Clinics between January 2012 and April 2017 were analysed. The apical root configuration was verified by navigating 0.1 mm/0.1 mm, in the three planes, axial, coronal, and sagittal sections on CBCT images, from the root canal entrance to the apical foramen, as well as from the apical direction to the crown. The standard reference for apical root form corresponded to the long axis of the tooth. The root forms and their frequency were characterised according to the classification proposed by Levander and Malmgren (1988). The qualitative variables were analysed by the Chi-square test. The level of significance was p-value <0.05. Results: A total of 400 maxillary anterior teeth (central and lateral incisors; n=200 each) from 167 patients (101 women; mean age was 41.8±16.20 years) were analysed. The most common apical root form presented in the central incisors was the blunt root {99 (49.5%)}, followed by pipette-shaped root {69 (34.5%)}. The less frequent was the short root {13 (6.5%)} (p-value <0.001). In the lateral incisors, the highest frequency presented was lacerated root {111 (55.5%)}, followed by blunt root {47 (23.5%)}, and pipette- shaped root {37 (18.5%)} (p-value <0.001). Conclusion: Maxillary central incisors had a higher frequency of rhomboid (blunt) root morphology, while lateral incisors had a higher frequency of curved (lacerated) root form.