Robust Teeth Detection in 3D Dental Scans by Automated Multi-View Landmarking

Landmark Detection in 3D, Polygonal Models, Multi-View Deep Neural Networks, RANSAC, U-Net, Heatmap Regression, Teeth Detection, Dental Scans

Landmark detection is frequently an intermediate step in medical data analysis. More and more often, these data are represented in the form of 3D models. An example is a 3D intraoral scan of dentition used in orthodontics, where landmarking is notably challenging due to malocclusion, teeth shift, and frequent teeth missing. Whats more, in terms of 3D data, the DNN processing comes with high requirements for memory and computational time, which do not meet the needs of clinical applications. We present a robust method for tooth landmark detection based on the multi-view approach, which transforms the task into a 2D domain, where the suggested network detects landmarks by heatmap regression from several viewpoints. Additionally, we propose a post-processing based on Multi-view Confidence and Maximum Heatmap Activation Confidence, which can robustly determine whether a tooth is missing or not. Experiments have shown that the combination of Attention U-Net, 100 viewpoints, and RANSAC consensus method is able to detect landmarks with an error of 0:75 0:96 mm. In addition to the promising accuracies, our method is robust to missing teeth, as it can correctly detect the presence of teeth in 97.68% cases.