Crown-Root Angle Measurement in Permanent Central Incisors

Abstract

˚˚ ABSTRACT: The anatomical variations of teeth are directly related to the esthetics achieved in orthodontic treatment. These variations include the dental axes, such as the long crown axis and the long root axis. For this reason, these axes and the angle formed by their intersection, or crown-root angle, have been studied using several methodologies, mainly in central incisors. This study aimed to propose the visual- spatial processing as a method to determine the long crown axis and the long root axis, and thus measure the angle between these axes (crown-root angle) in the permanent upper and lower central incisors. The study had a quantitative, descriptive, observational and cross- sectional approach. The study sample consisted of 100 Cone-beam computed tomography (CBCT) images: 50 of permanent upper central incisors and 50 of permanent lower central incisors. The crown-root angle was measured considering the long crown axis and the long root axis. The mean crown root angle in the upper central incisors was 21.34 (cid:176) , with a standard deviation (SD) of 4.41…; for the lower central incisors, the mean value was 20.05… with a SD of 4.18…. This study suggests that the visual-spatial processing can be a valid method to determine the long crown axis and the long root axis, also with the advantage of not requiring specific instruments and anatomical reference points, which simplifies the tracing of axes and thus measurement of the crown-root angle.