A common question for individuals with dental work is whether a Magnetic Resonance Imaging (MRI) scan can be safely performed with a permanent retainer. This article clarifies the compatibility of permanent retainers with MRI scans, providing essential information for those preparing for the procedure.
Permanent Retainers and MRI Basics
A permanent retainer, also known as a fixed or bonded retainer, is a thin wire custom-fitted and glued to the back surfaces of teeth, typically after orthodontic treatment. These retainers maintain tooth alignment and are often made from materials like stainless steel, titanium, or a flexible fiber composite. The wire is bonded using a dental adhesive, providing a long-term solution for preventing tooth shifting.
Magnetic Resonance Imaging (MRI) is a medical imaging technique that uses a powerful magnetic field and radio waves to create detailed images of organs and soft tissues. The MRI machine aligns hydrogen protons in the body’s tissues using its strong magnetic field. Radiofrequency pulses momentarily disrupt this alignment, and as protons return to their original state, they emit signals that the scanner converts into images. Metal objects within this strong magnetic field can interact with the MRI system, which is why concerns about dental retainers arise.
Safety Considerations with Metal Implants
Concerns with metal in an MRI environment involve magnetic interaction, heating, and image artifact. Ferromagnetic materials, strongly attracted to magnets, can experience forces in the scanner. However, for small, fixed objects like permanent retainers, the risk of significant movement or dislodgment is low. Many modern retainers are made from non-ferromagnetic materials like stainless steel or titanium, which react minimally to the magnetic field.
Radiofrequency (RF) energy in MRI can cause metallic objects to heat up. However, significant heating from small, thin wires like retainers is rare. Studies show that substantial heating does not typically occur with dental wires when scanning within safety guidelines. The most common concern with permanent retainers during an MRI is image artifact or distortion. Metal can interfere with the magnetic field, leading to signal voids or distorted areas in images, especially if the scan focuses on areas near the head or neck.
Preparing for Your MRI Scan
Individuals with permanent retainers scheduled for an MRI scan should inform their healthcare provider and the MRI facility about the retainer before the appointment. This disclosure is crucial for ensuring safety and image quality. Patients will complete a detailed screening questionnaire about any metal in their body; provide thorough and accurate information.
MRI staff will assess the retainer’s type, material, and location relative to the scan area to determine any risks or impact on image quality. While generally safe to undergo an MRI with a permanent retainer, staff awareness allows for informed decisions. In most cases, the retainer remains in place, but adjustments to the MRI sequence can mitigate potential issues. Rarely, if the retainer is highly reactive or significantly obscures a critical area, removal might be suggested by an orthodontist, though this is uncommon.
During and After the MRI
If the permanent retainer remains in place during the MRI scan, the patient will be monitored by the technologist. Patients should immediately report any unusual sensations, such as warmth, tingling, or discomfort, to the technologist. For retainers, such sensations are typically minor and infrequent.
The primary impact of a permanent retainer on an MRI might be on image clarity, particularly if the scan focuses on the head or neck. Metal can cause localized signal loss or distortions, making interpretation more challenging in that specific area. Once the scan is complete, individuals can typically resume normal activities. Issues related to permanent retainers post-scan are extremely rare. Patients should contact their orthodontist or doctor if they notice any changes to their retainer or teeth after the scan.