The aim of this review article is to describe the behaviour of dental alloys during the magnetic resonance imaging procedure. Mechanical and physical effects of a high frequency magnetic field are discussed. They may cause a movement or heating of metal objects present in the body, which can lead to a potential health risk for patients undergoing this examination. Metal objects with positive magnetic properties can influence magnetic resonance scans and the results of this procedure. Such negative effects are documented in experiments, theoretical studies and articles evaluating clinical trials. The safety of magnetic resonance and the compatibility of dental alloys must always be considered prior to the magnetic resonance imaging procedure.