3DTeethSeg'22: 3D Teeth Scan Segmentation and Labeling Challenge

Teeth localization, segmentation, and labeling from intra-oral 3D scans are essential tasks in modern dentistry to enhance dental diagnostics, treatment planning, and population-based studies on oral health. However, developing automated algorithms for teeth analysis presents significant challenges due to variations in dental anatomy, imaging protocols, and limited availability of publicly accessible data. To address these challenges, the 3DTeethSeg'22 challenge was organized in conjunction with the International Conference on Medical Image Computing and Computer Assisted Intervention (MICCAI) in 2022, with a call for algorithms tackling teeth localization, segmentation, and labeling from intraoral 3D scans. A dataset comprising a total of 1800 scans from 900 patients was prepared, and each tooth was individually annotated by a human-machine hybrid algorithm. A total of 6 algorithms were evaluated on this dataset. In this study, we present the evaluation results of the 3DTeethSeg'22 challenge. The 3DTeethSeg'22 challenge code can be accessed at: https://github.com/abenhamadou/3DTeethSeg22_challengeComment: 29 pages, MICCAI 2022 Singapore, Satellite Event, Challeng

Studies on neutron diffraction and X-ray radiography for material inspection

Among the different probes to study the structures of the bio and structural materials, X-ray and neutron are widely used because of their distinctive usefulness in investigating different structures. X-ray radiography and neutron diffraction are two widely known non-destructive techniques for material inspection. Here we demonstrate the design of neutron diffractometer with low power source and analyze the digital image produced by the X-ray radiography instead of neutron diffraction because of the availability of the data. Neutron diffraction is a powerful tool for understanding the behavior of crystal structures and phase behaviors of materials. While neutron diffraction capabilities continue to explore new frontiers of materials science, such capabilities currently exist in limited places, which require high neutron flux. The study seeks to design a low-resolution neutron diffraction system that can be installed on low power reactors (e.g. 250 kW thermal power). The performance of the diffractometer is estimated using Monte-Carlo ray-tracing simulations with McStas with an application in material science. Both monochromatic and polychromatic configurations are considered in order to maximize the net diffracted neutron flux at the detectors with reasonable resolution. On the other hand, considering X-ray radiography as a structure inspecting technique, analysis of dental X-ray panorama is performed for the detection of oral lesions. A novel automatic computer-aided method to identify dental lesions from dental X-ray is presented. Morphological operations, intensity profile analysis, automated seed point selection, region growing, feature extraction and neural network application are carried out to perform the job. Results show that the performance of the proposed method surpasses existing automated methods utilizing dental X-rays --Abstract, page iii

Cone Beam Computed Tomography in Orthodontics

Cone beam computed tomography (CBCT) is an important source of three‐dimensional volumetric data in clinical orthodontics. Due to the progress in the technology of CBCT, for orthodontic clinical diagnosis, treatment and follow‐up, CBCT supply much more reliable information compared to conventional radiography. The most justified indications for the use of CBCT in orthodontics are the existence of impacted and transposed teeth. For the management of the impacted teeth, CBCT enhances the ability to localize these teeth accurately and to assess root resorption of adjacent teeth. Patients with craniofacial anomalies like cleft palate cases, the abnormalities of the temporomandibular joint contributing malocclusion, evaluation of airway morphology in obstructive sleep apnea cases, patients needing maxillary expansion or planning orthognathic surgery in severe skeletal discrepancies are also listed among the indications of using CBCT in orthodontics. CBCT is useful in identifying optimal site location for temporary skeletal anchorage device. The use of CBCT for the assessment of treatment outcomes and evaluation of cervical vertebral maturation are still controversial issues. It should be kept in mind that before using CBCT, justification and evaluation of risks and benefits are needed. In order to minimize the radiation dose, the exam should include only the areas of interest