Can You Get an MRI With a Permanent Retainer?

In almost all cases, yes, you can safely undergo an MRI with a permanent retainer in place. The retainer does not need to be removed for the scan to proceed. Research consistently shows that the heating and physical forces produced during MRI exposure are not hazardous to patients with bonded retainers, though the metal wire can distort the images in ways that matter depending on what the scan is looking at and what your retainer is made of.

Why the Concern Exists

MRI machines use extremely powerful magnets along with radiofrequency energy, and metallic objects inside the scanner can interact with those fields in three ways that worry people. First, the magnet can pull or twist ferromagnetic metals. Second, the radiofrequency pulses can heat metal up. Third, any metal in the body can scramble the signal and create blind spots or distortions in the resulting images. Permanent retainers, the thin wires bonded to the backs of your teeth after braces come off, are typically made from stainless steel, and stainless steel is at least partly ferromagnetic. So the worry is understandable.

A study testing orthodontic retainer wires at a standard 1.5 Tesla MRI found that steel retainer wires experienced considerable rotational and translational forces, with translational forces measured at roughly 9 to 28 times the force of gravity on those wires. That sounds alarming on paper. But the critical detail is that these wires are bonded directly to your teeth with dental composite. The forces act on a wire that is cemented in place, not floating loose. The study’s recommendation was not to remove retainers before scanning but rather to check that the bonds are secure beforehand.¹

Heating Is Minimal

The radiofrequency energy an MRI uses can theoretically heat metal, and a wire sitting against your teeth and gums is not somewhere you want unexpected warmth. Researchers have tested this directly. An in vitro study at 7 Tesla, a field strength far stronger than what is used clinically for most scans, found that even at the wire length most prone to heating (about 47 mm), no substantial temperature increase occurred when the scanner operated within standard safety limits for the head.² A separate study testing multibraided retainer wires of different diameters found temperature increases ranging from about 0.36 to 1.18 degrees Celsius after MRI exposure. Those changes were statistically measurable but not clinically meaningful, posing no risk to tooth pulp or surrounding soft tissue.³

A systematic review of MRI compatibility for orthodontic brackets and wires concluded broadly that heating and debonding effects during MRI exposure were not hazardous for patients, though the authors noted that some wires with higher temperature changes might warrant inserting a spacer between the appliance and the oral mucosa as a precaution.⁴ In clinical use, spacers are rarely necessary for the thin wires found in permanent retainers. The same study on multibraided wires also checked whether the bond strength between the retainer and the teeth changed after MRI exposure, and it did not, meaning the retainer stays stuck to your teeth just as firmly after the scan as before.³

One small clinical report on patients with gold solder-filled retainer wires noted that two out of three patients reported no adverse effects at all during craniofacial MRI, including no sensation of heat. The third patient reported a headache during the exam, though headaches are a common complaint during MRI even without any dental hardware.⁵

The Real Issue Is Image Quality, Not Safety

Where permanent retainers genuinely cause trouble is not in hurting you but in messing up what your doctor can see on the scan. Metal in or near the area being imaged creates “susceptibility artifacts,” which are dark voids and bright signal pile-ups that obscure the surrounding anatomy. How much distortion you get depends heavily on what your retainer is made of, how thick and long the wire is, and how close the scan’s target area is to the retainer.

Steel retainers, especially the flat rectangular type, create the largest artifacts. One study found rectangular steel retainers produced artifact volumes exceeding 18,000 cubic millimeters in the upper jaw and nearly 16,000 cubic millimeters in the lower jaw, with substantial diagnostic impairment in areas near the wire.⁶ The common twistflex steel retainer, which is what most people have, also causes artifacts, though the pattern varies. One study found twistflex retainers caused distortion in nearly half of test areas close to the retainer, affecting the tongue and jaw areas in particular.⁷ Another study measured twistflex artifacts as substantially smaller than rectangular steel but still diagnostically relevant in some views.⁶

A systematic review across dental materials confirmed that retainers caused only moderate artifacts and that those artifacts were restricted to part of the oral cavity, not spreading through the entire scan.⁸ This is why most radiologists proceed without concern when the MRI is imaging your knee, shoulder, spine, or brain. The artifacts stay local. If the scan target is far from your mouth, the retainer is essentially invisible to the machine.

When the Scan Targets the Head or Neck

The story gets more complicated when the MRI is aimed at structures near your retainer. Dental MRI, temporomandibular joint (TMJ) imaging, tongue or floor-of-mouth scans, and certain head and neck cancer staging protocols all place the area of interest close to the wire. In those situations, a steel retainer can genuinely obscure the anatomy your doctor needs to see.

Having both an upper and lower retainer makes it worse. The study on twistflex retainers found that having maxillary (upper) retainers alone, or both upper and lower retainers, increased the distortion beyond what a single lower retainer produced.⁷ For standard brain imaging, though, the picture is more reassuring. Research using both 1.5 Tesla and 3 Tesla scanners found that fixed retainers caused no artifacts in structures above the upper jaw when appropriate scan sequences and bandwidth settings were used, meaning they do not need to be removed before a brain MRI.⁹

Field Strength Matters

Most clinical MRI scanners run at either 1.5 Tesla or 3 Tesla. Higher field strength means better image resolution in general, but it also amplifies the artifacts caused by metal. The twistflex retainer study found greater distortion at 3 Tesla than at 1.5 Tesla.⁷ An in vivo and in vitro comparison across both field strengths showed that images from the 3 Tesla scanner had a higher number of major artifacts than those from the 1.5 Tesla scanner across all types of orthodontic appliances tested.⁹

If you know your scan will use a 3T machine and the area being imaged is near your mouth, it is worth mentioning your retainer to the radiologist ahead of time. They may be able to adjust the imaging sequence. Techniques like turbo spin echo with high readout bandwidth or advanced metal artifact reduction protocols can significantly reduce the distortion. The same study that flagged 3T as more artifact-prone also found that applying turbo spin echo with high readout bandwidth at 3T suppressed artifacts from fixed retainers enough that they did not need to be removed even for scans of nearby structures.⁹

Retainer Material Makes a Huge Difference

Not all permanent retainers are created equal when it comes to MRI. The type of wire your orthodontist bonded behind your teeth years ago determines almost everything about how much trouble it will cause in the scanner.

Steel retainers, the most common variety, are the worst offenders for image artifacts. Within that category, flat rectangular steel wires produce the most distortion, while the braided twistflex steel wires are somewhat better but still problematic for nearby structures. Retainers made from titanium or gold, however, behave very differently. A direct comparison found that titanium grade 1 retainers produced artifact volumes of only about 70 cubic millimeters in the upper jaw, titanium grade 5 produced about 47 cubic millimeters, and gold retainers produced just 23 cubic millimeters. All retainers made of these precious-alloy or biocompatible materials had zero impact on image quality, with perfect visibility scores for all anatomical landmarks both inside and outside the retainer area.⁶

Fiber-reinforced composite retainers, which contain no metal at all, are another option. A preliminary study found that these retainers did not distort images at all and would never need to be removed before scanning.¹⁰ Titanium retainers and multi-stranded stainless steel retainers caused only minimal distortion in the same study, and the resulting images were still considered diagnostic.¹⁰

This matters practically because if you are someone who expects to need regular MRIs, for monitoring a neurological condition or tracking a known issue in the head and neck region, your orthodontist could place a titanium, gold, or fiber-reinforced composite retainer instead of stainless steel. Most patients do not have a choice retroactively, but it is worth knowing for future decisions or for anyone still in orthodontic treatment.

What to Tell Your MRI Team

Before any MRI, you will fill out a safety screening questionnaire that asks about metal in your body. Permanent retainers should be disclosed, even though they almost never prevent the scan from happening. The MRI technologist and radiologist need to know the retainer is there for two reasons: so they are not startled by unexpected artifacts on the images, and so they can choose sequences that minimize distortion if the scan area is near your mouth.

You do not need to have the retainer removed ahead of a routine scan. The evidence consistently supports leaving it in place. If your doctor orders a dental MRI or a very targeted scan of the jaw or tongue and you have a steel retainer, the radiologist might discuss whether the retainer could compromise the diagnostic value of the scan. Even then, removing it is a last resort. Adjusting the imaging protocol usually solves the problem. The only scenario where removal might be recommended is when the bond is already loose or partially broken, since an unfastened wire in a strong magnetic field could theoretically move. This is why the recommendation from multiple studies is to confirm that the retainer bonds are intact before scanning, not to take the retainer out.¹

Emergency Scans and Retainers

In an emergency, like a stroke or a suspected brain hemorrhage, nobody is going to delay your MRI to remove a retainer. Nor should they. The research supports this approach. Retainers do not produce dangerous forces when bonded, they do not heat to harmful levels, and they do not compromise the diagnostic quality of brain scans above the upper jaw. Emergency radiologists are trained to interpret images with metal artifacts from dental work, surgical hardware, and implants. Your retainer is among the least of their concerns. If anything in the scan area is obscured, they can note it and, if needed, follow up with a repeat scan under more controlled conditions once the emergency has passed.

How Permanent Retainers Compare to Other Dental Metal

People with permanent retainers often have other dental metalwork too: crowns, bridges, implants, or amalgam fillings. All of these interact with MRI fields to some degree. The retainer wire is actually relatively tame compared to some alternatives. Dental implants made from titanium are widely considered MRI-safe and create very small artifact footprints. Amalgam fillings, which contain mercury, silver, and tin, produce minimal artifacts. Cobalt-chromium crowns and frameworks, on the other hand, can produce artifacts comparable to or larger than a steel retainer wire.

What sets the retainer apart from other dental metal is its length. A retainer wire runs across several teeth, typically spanning from canine to canine, giving it a longer profile than a single crown or implant. Longer wires interact more with the radiofrequency field, which is partly why the heating studies focused on identifying the wire length most prone to energy absorption. The 47 mm length identified as the peak for heating at 7 Tesla corresponds roughly to a standard lower retainer wire.² Even at that worst-case length and at a field strength well above what most patients will ever encounter, the heating stayed within safe limits.

If You Are Getting a New Retainer

For people still deciding on or about to receive a permanent retainer, the MRI evidence gives some practical guidance. If you have a medical condition that will require repeated MRI scans of the head or neck, ask your orthodontist about titanium or gold retainers. These materials produce artifact volumes hundreds of times smaller than steel and have no measurable impact on image quality.⁶ Fiber-reinforced composite retainers are another route, eliminating the metal question entirely, though they come with different durability and cost trade-offs that your orthodontist can walk you through.¹⁰

For the majority of patients who already have a stainless steel retainer and need a routine MRI, the evidence is clear: keep the retainer, get the scan, and let the radiology team know it is there. The safety profile is well established, and the artifact issue is manageable with modern scanning techniques. The days when any metal in the body meant canceling the MRI are long gone.