THREE-DIMENSIONAL ASSESSMENT OF TOOTH MOVEMENT: A NEW METHOD FOR SUPERIMPOSITION OF DIGITAL MODELS

Abstract

Superimposition of the patient’s two-dimensional (2D) cephalograms is traditionally indicated whenever evaluation of orthodontic treatment and/or growth is required. Recently, superimposing the three- dimensional (3D) digital models or cone beam computed tomography (CBCT) images made it possible to assess these changes in a 3D manner. The current digital model software available in the orthodontic market rely on the surface-based best fit method for superimposing the digital models. This is because of the simplicity of the procedure for the end users; yet the systemic errors that may occur are totally neglected. The best fit superimposition method misses the remodeling that occurs in the anatomy of the treated patients. It was thus suggested that using stable anatomical landmarks as a reference plane for the superimposition process yields more accurate results. The aim of this project was to identify and evaluate a user-friendly, valid, and reliable technique to superimpose digital maxillary models on stable anatomical landmarks and perform subsequent 3D assessment of the orthodontic tooth movement to confirm reliability. We collected data from four different studies to investigate a newly introduced algorithm and software for superimposition of the digital dental models using stable anatomical landmarks. The technique offered an innovative method for 3D assessment of tooth movement. In addition, the new software algorithms studied in the current project were found to offer a valid and reliable technique for superimposition and were still simple to use.