How Dental Crowns Can Affect An MRI Scan

For most patients who require magnetic resonance imaging (MRI), the experience will be an isolated one. That being said, there are a range of conditions that require patients to receive occasional MRI scans on an ongoing basis. This is typically reserved for certain chronic physical and neurological disorders. If your physician is recommending that you receive an MRI, you will be informed about the device's various restrictions. One of the most relevant restrictions is the strong magnetic fields that the device must generate. Certain dental restorations (such as dental crowns) can affect your ability to receive an MRI. But why is this the case, and does it mean you won't be able to undergo an MRI?

Magnetic Pull

The presence of a metal dental crown can disrupt the MRI's effectiveness, which negates the use of the scan as a diagnostic tool. Additionally, the activation of the machine will create a powerful magnetic pull on metal dental crowns. The magnetic pull of the machine will actively be trying to attract any metal in its field. It will, quite literally, try to pull any metal dental crowns off your teeth. While dental crowns may not dislodge when subjected to an MRI, they can become warped and damaged, which poses a risk to the underlying tooth.

The Composition of a Crown

The good news is that most dental crowns are not in fact metal. Some types of crowns made from precious metal (such as gold) will not necessarily affect an MRI scan either. The problem is with ferromagnetic metals, which are metals that will respond to a magnetic field. This applies to some porcelain-fused-to-metal crowns. These are crowns that have a porcelain shell attached to a metal frame. While stainless steel crowns are uncommon in adults, they can sometimes be used as a temporary crown while a permanent replacement is being fabricated. A stainless steel crown is not compatible with an MRI. 

Talk to Your Dentist

Inform your doctor about any metal dental restoration work you may have. They'll enquire about this possibility anyway and will need to determine whether your diagnostic testing is still possible with the presence of your metal crowns. The precise nature of the crown will need to be determined, and you should ask your dentist about this. You might not know the materials used in your crown or whether any metals are ferromagnetic or not. Your dentist will be able to provide this information. When any problematic metals are present, it might also be that you'll need to have these dental crowns replaced with crowns made entirely of porcelain or composite resin.

Be sure to disclose the presence of any metal dental crowns as soon as your doctor mentions the need for an MRI. Your dentist can help you to determine the nature of your dental crowns and can replace them as needed.