CT-scan
A CT scan also known as CAT-scan, axial tomography, computer aided tomography, or computerized tomography is a medical imaging exam that uses X-rays to study and analyze a region of the body in 3D with high resolution which is then cut in very thin slices by a computer. This exam allows the clinician to see bone structures as well as soft tissue structures such as muscles of the maxillo-facial complex.

In dentistry, a CT scan may be prescribed for the following reasons : 

• Pre-surgical dental implant evaluation of the alveolar bone 
• Pre-surgical evaluation of the inferior alveolar canal position and relation with the roots of impacted teeth such as wisdom teeth 
• TMJ (temporomandibular joint) assessment for degenerative joint disease and morphology
• Characterization of pathologies of the jaws such as cysts and tumors.
• Trauma or fractures of the jaws
• Processing of a 3D stereolithic model for better surgical planning 
• Virtual surgical implant planning with third party software

MRI or magnetic resonance imaging
Magnetic resonance imaging or MRI is an imaging modality that reveals soft tissues of the body. MRI produces high resolution and detailed images in two and three dimensions to differentiate normal soft tissue from abnormal ones. 

In dentistry, MRI is extremely valuable in assessing the temporomandibular joints (TMJ). It allows to visualize the articular disc’s position, to differentiate the different compartments of the articular space and determine if there is fluid in the joint, edema in the marrow and inflammation in the surrounding muscles. 

Thanks to MRI, pathologies can be detected at an early stage and more easily, allowing for more efficient treatment planning. 

MRI does not use X-rays.