Three-dimensional orthodontic and surgical study of third molars: Magnetic resonance versus Cone Beam Computed Tomography

The aim is to assess 3D volumetric anatomical reconstruction of the third molars and the relationships with the inferior alveolar nerve canal (IAN) by Magnetic Resonance Imaging (MRI) versus Cone Beam Computed Tomography (CBCT). The precise localization of third molars and the study of their relationships with the inferior alveolar nerve canal (IAN) is critical for a correct surgical approach. Magnetic Resonance Imaging (MRI) is a technique applied in various branches of medicine, it allows to obtain tissue images using their behavior in a high intensity magnetic field. Twenty patients underwent CBCT and MRI with a new 3D protocol, that provides Dicom data acquisition that can be imported into three-dimensional reconstruction and visualization software. It has been performed a segmentation of jaw bones and dental elements, and has been mapped the location of the inferior alveolar nerve. RESULTS: The volumetric MRI has resulted optimal for the virtual models of anatomical structures, especially the third molars and the IAN. The 3D MRI volumetric reconstruction resulted similar to 3D CBCT volumes (p<0.1). In this way the operator can see in the three planes in space, the structures of interest, with a dimensional ratio of 1:1. CONCLUSION: The results presented confirm the possibility of using this MRI technique for imaging 3D-volumetric study of dental and maxillo-mandibular structures. The main advantage in the application of MRI is the total absence of ionizing radiation delivered to the patient, however, have a greater execution time of the examination and data review.