Superimposition of 3D cone-beam CT models in orthognathic surgery

Alexandre Trindade Simões da MOTTA, Felipe de Assis Ribeiro CARVALHO, Ana Emília Figueiredo OLIVEIRA, Lúcia Helena Soares CEVIDANES, Marco Antonio de Oliveira ALMEIDA

Introduction: Limitations of 2D quantitative and qualitative evaluation of surgical displacements can be overcome by CBCT and three-dimensional imaging tools. Objectives: The method described in this study allows the assessment of changes in the condyles, rami, chin, maxilla and dentition by the comparison of CBCT scans before and after orthognathic surgery. Methods: 3D models are built and superimposed through a fully automated voxelwise method using the pre-surgery cranial base as reference. It identiies and compares the grayscale of both three-dimensional structures, avoiding observer landmark identiication. The distances between the anatomical surfaces pre and post-surgery are then computed for each pair of models in the same subject. The evaluation of displacement directions is visually done through color maps and semi-transparencies of the superimposed models. Conclusions: It can be concluded that this method, which uses free softwares and is mostly automated, shows advantages in the long-term evaluation of orthognathic patients when compared to conventional 2D methods. Accurate measurements can be acquired by images in real size and without anatomical superimpositions, and great 3D information is provided to clinicians and researchers.

Keywords: Cone Beam Computed Tomography. Three-dimensional image. Surgery, computer assisted. Computer simulation. Orthodontics. Surgery, Oral.

Saturday, November 23, 2024 02:20