MRI and Its Implications in Dentistry

Magnetic Resonance imaging (MRI) has become one of the most powerful diagnostic tools in radiology and diagnostic sciences. It is non-invasive and non-ionizing and the images are highly sensitive and specific with excellent soft tissue contrast. It gives excellent images of anatomic structures differing in proton density and other tissue characteristics. It can be used to assess intracranial and extracranial lesions particularly those involving the soft tissues. MRI has the shortcoming of being prone to magnetic susceptibility difference artefacts, caused by the presence of metallic materials such as dental restorative materials, implants and orthodontic appliances. All substances when placed in a magnetic field are magnetized to a degree which varies according to their magnetic susceptibility. Non precious dental alloys have the potential of causing image deformation or image voids. Dentists are not the only professionals implanting metal devices. Heart pacemakers and defibrillators, aneurysm clips, cochlear implants, insulin pumps, vascular stents and artificial joints are widely used in various branches of medicine. In some cases, it is not possible to carry out MRI due to extensive dental hardware with a high ferromagnetic content. Severe image distortion or an inability to perform the MRI scan due to dental restorations is a rare problem, but cannot be completely eliminated. This article has been written to educate the dentists on the implications of metallic dental restorations on MRI scans. Keywords: Magnetic resonance imaging, MRI, Dentistry, Dental materials, artefact, artifacts.