3D Analysis of the Upper and Lower Arches Using Digital Technology: Measurement of the Index of Bolton and Correspondence between Arch Shape and Orthodontic Arches

Abstract

Introduction: Due to the great development of digital technology, through CAD (Computer - Aided Design) and CAM (Computer - Aided Manufacturing) systems, digital models could be used in orthodontic treatment planning decision-making, as there are numerous studies in the literature that support the validity of measurements of digital models of anterior teeth and the total coefficient of Bolton analysis. The aim of the study was to compare the average length value of the current upper and lower arches with that of a hypothetical nickel-titanium wire and the accuracy of the Bolton index measurement. In the present study, 138 dental casts were analyzed using Ortho3Shape software. Using the Ortho3Shape software, it was possible to measure the real and ideal lower arch lengths and, with regard to Bolton analysis, the values of the anterior and total Bolton coefficients. By comparing the values obtained with those of the study by A. Anand Kumar et al. using CBCT and plaster casts, the reliability of the measurements obtained with such CAD/CAM orthodontic software was evaluated. Considering the validity of digital measurements demonstrated by the studies and systematic reviews in the literature, it can be stated that CAD/CAM digital models can be a viable alternative to plaster models in the coming years, as they can facilitate model preservation and retrieval. For future studies and research, it would be preferable to use intra-oral scanners (IOS) in order to ensure greater accuracy, requiring only one step and ensuring a better outcome for the patient.