Are dental implants a problem for an MRI scan?
Usually not, but you must declare them. According to the review by Chockattu and colleagues in Restorative Dentistry & Endodontics (2018), dental implants are made of non-ferromagnetic titanium and contain only traces of iron; these traces cause a loss of signal close to the metal surface, which is an image problem rather than a danger. The safety concern in MRI is with ferromagnetic objects, which the strong magnetic field can move or heat, which is why every patient is screened for metal before a scan.
For you this means: the radiology department decides how the scan is carried out, and it needs your information to do so. The NHS says you will be asked to fill in a form before the scan that asks whether you have any metal parts in your body, and gives surgical clips, a pacemaker and dental fillings or bridges as examples. North Bristol NHS Trust says dental fillings and bridges can be scanned, but the radiographers need to know about them to optimise the examination.
Do dental implants distort MRI images?
Yes, especially when the region being scanned is close to the implant. In one study cited by Chockattu and colleagues (Smeets et al., 2017), the MRI signal around titanium and titanium-zirconium implants was reduced up to 14.1 millimetres from the implant. Other studies found marked artefacts from titanium implants in all planes, and others only minor distortion that did not affect the reading. The results are therefore mixed.
The restoration on the implant also plays a part: according to the same review, the artefact volume was unfavourable for a titanium implant with a crown framework made of a non-precious metal alloy. If an MRI of your tongue, salivary glands, jaw joint or neck is planned, describe to the radiology team exactly which implants, crowns and bridges you have. To check the implants themselves, Smeets et al. consider CT and cone-beam CT (CBCT) better suited, because they are less affected by titanium artefacts.
Ceramic implants made of zirconia caused far fewer artefacts in most of the studies cited; the least distortion was seen with a zirconia implant and an all-zirconia crown. One study, however, found effects for zirconia in the midface similar to those of metal. Whether titanium or ceramic, MRI is only one of several considerations; the others are explained in our guide ceramic or titanium implants.
What if your denture is held by magnetic attachments?
Some removable dentures on implants are held by magnets: the magnet sits in the denture, and a metal keeper sits on the implant. This system needs particular attention before an MRI. The opinion of the Clinical Guideline Committee of the Japanese Society for Oral and Maxillofacial Radiology and the studies it cites highlight:
- The denture stays outside: a denture containing magnets is removed before entering the scanner room; the society reports a case in which a denture stuck to the MRI machine.
- Keepers on the implants should be removed if possible: the society strongly recommends removing the keepers for the duration of the MRI and advises screw-retained keepers that can be taken off temporarily. Chockattu and colleagues cite studies in which magnetic keepers fixed to implants caused large artefacts and had to be removed for comprehensive head and neck MRI.
- Heating and forces: Hasegawa and colleagues (2015) measured a maximum temperature rise of 1.42 °C at 3 tesla; the forces acting on the keepers, however, tended to exceed acceptable limits, which is why the authors recommend checking the components before and after the MRI.
Removing a keeper is a dental procedure. Which attachment systems exist is explained in our guide snap-on dentures on implants.
What should you sort out before an MRI at home?
- Declare implants, crowns and bridges when booking the appointment and on the MRI safety questionnaire.
- Take your implant card. Manufacturer, model and batch number on the card shorten the radiology team’s search for information about your implants.
- Remove removable dentures before the scan and say whether they contain magnets.
- If the region being scanned is close to your mouth, mention possible image distortion.
- After the MRI, have the fit of magnetic components and of the denture checked.
Do dental implants set off airport metal detectors?
This cannot be predicted with certainty. Whether a detector alarms depends mainly on the amount of metal and on the machine’s settings. The data come mostly from studies with orthopaedic implants:
- Kamineni and colleagues (2002) tested twelve patients with implants and 60 implants outside the body at Stansted Airport. Walk-through detectors missed some implants, depending on walking speed; hand-held detectors found almost all. For stainless steel as for titanium, the mass of the implant was decisive. The authors advise carrying proof of the implant.
- Basu and colleagues (1997) found that most plates and screws and a single joint replacement did not trigger an alarm, whereas three or four joint prostheses together did.
Dental implants were not included in these studies. A single dental implant is far smaller than a hip or knee prosthesis, so the likelihood of an alarm is probably low. We have no direct measurement with dental implants, and several implants, metal frameworks or sensitively set hand-held detectors can change the outcome.
What should you do at security screening?
The US Transportation Security Administration (TSA) advises declaring metal implants before screening; if the metal detector alarms, a hand search follows. You can tell the staff beforehand that you have dental implants and show your implant card if asked. Different rules apply to electronic devices such as pacemakers: the TSA advises not walking through the detector and speaking to your doctor before the flight.
What is the Rönesans implant card for?
After implant surgery you receive an implant card; for each implant it carries the manufacturer’s official label with the diameter, length and batch number, and a QR code for checking that the implant is genuine. The make and model of your implants are also listed in your written treatment and cost plan. Show the card to the radiology team before an MRI and, if needed, at the airport; it quickly documents what you have in your mouth.
When you leave, you also receive a copy of your treatment summary and copies of your X-rays. If you have an MRI coming up or wear a removable denture on implants, tell us at your check-up or on WhatsApp at +90 532 363 49 54. The treatment options are described on our pages about implant-supported dentures and dental implants, and support after your return on aftercare and follow-up.