The Safety of an MRI for Dental Implants

Dental implants can pose difficulties for an individual having an MRI (magnetic resonance imaging), but do not automatically rule out undergoing the procedure, according to Frank G. Shellock, PhD. Shellock has studied the safety and biological effects of magnetic resonance imaging for 25 years and has identified several areas of concern for those with dental implants.

Demagnetization

• Dental implants may use magnets to hold the appliance in place. An MRI machine uses powerful magnets that can demagnetize and damage the magnets in the implant, necessitating surgery to repair or replace the appliance. Implants made of ferromagnetic materials use counter-force to keep them in place and appear safe when used in an MRI system operated at 3-Tesla (a measurement of the concentration of a magnetic field) or below.

Reduced Image Quality

• Studies of image quality in individuals with dental implants showed 12 of 16 had evidence of deflection of the MRI's magnetic field that resulted in decreased quality of the image. The MRI may show image artifacts, features that are visible on the image but are not really present.

Patient Injury

• The magnetic field may exert sufficient force that a dental implant can dislodge and cause injury to the individual; however, implants properly anchored in surrounding tissue should not cause a problem. The effects of MRI-caused heating of the implant at 3-Tesla is not known.