Introduction
If you have a metal dental crown and you have been referred for an MRI scan, it is entirely natural to feel uncertain. Many patients in London ask their dentists — or turn to online searches — to find out whether their dental restorations could cause problems during magnetic resonance imaging. It is a common and entirely reasonable concern.
Metal dental crowns have been used in dentistry for decades, and millions of people worldwide have them. However, the rise of MRI as a routine diagnostic tool means that more patients than ever are asking questions about how their dental work might interact with powerful magnetic fields.
This article aims to provide clear, balanced educational information about metal crowns and MRI safety. It will explain what types of metals are commonly used in dental crowns, how MRI technology works, what the current understanding is around safety, and when speaking to both your dentist and your radiologist or medical team may be appropriate. Individual circumstances always vary, and a clinical assessment is the most reliable way to address personal concerns.
Featured Snippet Answer
Are metal dental crowns safe in MRI?
Metal dental crowns are generally considered safe during MRI scans, though this depends on the specific alloy used in the crown. Most modern dental crown metals, such as gold alloys and non-magnetic base metals, are not significantly affected by MRI magnetic fields. However, some older alloys may contain ferromagnetic components. Always inform your radiographer and dentist before any MRI procedure.
What Are Metal Dental Crowns Made Of?
A dental crown is a cap placed over a damaged, weakened, or heavily restored tooth to restore its function, shape, and appearance. Metal crowns have long been valued for their durability and strength, particularly on back teeth where biting forces are greatest.
The term "metal crown" actually covers a broad range of materials, and this distinction is important when considering MRI safety.
Common metals used in dental crowns include:
- Gold alloys — These are among the oldest and most trusted dental crown materials. Gold is largely non-magnetic and is generally well-tolerated in MRI environments.
- Base metal alloys — These include nickel-chromium (Ni-Cr) and cobalt-chromium (Co-Cr) combinations, which are widely used for their strength and lower cost. These alloys are typically non-ferromagnetic.
- Stainless steel — More commonly used for temporary crowns or in children's dentistry. Some stainless steel formulations may have low-level ferromagnetic properties.
- Porcelain-fused-to-metal (PFM) crowns — These combine a metal substructure with a porcelain outer layer for aesthetics. The metal component is typically a base metal or gold alloy.
Understanding which type of metal your crown contains is an important first step before undergoing an MRI. Your dental records should contain this information, so speaking with your dentist prior to your scan is always advisable.
How Does MRI Technology Interact with Metal?
MRI — magnetic resonance imaging — uses powerful magnetic fields and radiofrequency pulses to produce detailed images of the body's internal structures. Unlike X-rays, MRI does not use ionising radiation, which is one of the reasons it has become such a widely used diagnostic tool.
The key concern with metal in an MRI environment is ferromagnetism — the property of certain metals to be attracted to, or influenced by, magnetic fields. Strongly ferromagnetic objects can be pulled or deflected by the MRI magnet, which poses an obvious safety risk if the object is inside or attached to the body.
Dental crown metals are generally assessed in three ways during MRI safety evaluations:
- Magnetic susceptibility — How strongly does the metal respond to the magnetic field?
- Heating effects — Can radiofrequency energy cause the metal to heat up?
- Image artefacts — Can the metal distort the MRI image quality in nearby areas?
Most dental alloys used in modern crowns have low magnetic susceptibility, meaning they are unlikely to move or cause harm. However, they can occasionally produce localised image artefacts — distortions or shadowing on the MRI image — particularly if the scan is targeting the head, neck, or jaw area. This does not usually affect scans of other parts of the body.
Are Metal Crowns Safe During an MRI? The Current Understanding
The reassuring reality for most patients is that modern dental metal crowns are generally considered MRI-compatible, provided they are made from non-ferromagnetic or weakly ferromagnetic alloys. This is consistent with guidance from MRI safety research organisations and the wider radiological community.
Gold alloys, cobalt-chromium alloys, and nickel-chromium alloys — the materials most commonly used in dental crown construction — are typically classified as MRI-safe or MRI-conditional. This means they are unlikely to pose a risk of movement or significant heating during a standard clinical MRI scan.
That said, there are nuances worth noting:
- Older crowns placed many years ago may have been made from alloys that are less commonly used today, and their precise composition may be uncertain.
- Image quality near the crown may be affected, which is relevant if the MRI is targeting the head or jaw.
- Multiple restorations — patients with several metal crowns, bridges, or implants — may warrant additional discussion with their radiographer.
It is important to stress that this is general educational information. Individual assessment remains essential. The radiographer conducting your MRI is trained to evaluate the safety of all metallic implants and restorations before proceeding, and they will ask you to complete a safety screening questionnaire.
If you are unsure about the composition of your crown, your dentist may be able to retrieve laboratory records or advise accordingly. Explore our dental crowns treatment page for further information about crown materials and their clinical applications.
MRI Safety Screening: What to Expect
Before any MRI scan, patients undergo a thorough safety screening process carried out by trained radiographers. This is standard practice across NHS and private healthcare settings in the UK.
During MRI screening, you will typically be asked:
- Whether you have any metal implants, dental work, or restorations
- Whether you have had any previous surgeries involving metal devices
- The nature and location of any known metallic items in or on your body
What you should do before your scan:
- Inform the MRI department about all dental restorations, including crowns, bridges, implants, and orthodontic appliances
- Contact your dental practice to find out the composition or type of crown you have fitted
- Bring any dental documentation you have to your MRI appointment if possible
- Be open and transparent with your radiographer — they are there to ensure your safety
Most importantly, do not assume your crown is safe simply because it is dental in origin. Equally, do not assume it is unsafe and refuse a scan that your doctor has recommended. The appropriate course of action is to communicate clearly with both your medical team and your dental practice.
Image Artefacts and Their Implications
One aspect of metal crowns and MRI that patients sometimes overlook is the issue of image artefacts. Even when a metal crown poses no safety risk in terms of movement or heating, it can affect the quality of the MRI image in its immediate vicinity.
Artefacts appear as distortions, signal voids (dark areas), or shadowing around the metallic object in the scan image. The severity depends on:
- The type of metal — higher-susceptibility metals cause more significant artefacts
- The field strength of the MRI scanner — higher-tesla machines may produce more pronounced artefacts
- The proximity of the scan target to the crown — scans of the brain, jaw, or neck are more likely to be affected than scans of the knee or abdomen
For most whole-body or peripheral MRI scans, artefacts from dental crowns are unlikely to interfere with the diagnostic information the radiologist needs. When the scan is focused on the head and neck region, however, the radiologist may need to take this into account when interpreting the images.
Your medical team will be aware of this and will factor it into the diagnostic process. If there is a clinical concern that artefacts could compromise the value of the scan, your radiologist may discuss alternative imaging modalities or techniques.
When Professional Advice May Be Appropriate
Whilst the general educational information in this article applies to most patients, there are certain situations where seeking professional guidance before an MRI is particularly advisable:
- You are unsure of the composition of your crown — particularly if it was placed many years ago or by a dental practice you no longer attend
- You have multiple metal restorations — crowns, bridges, implants, or retained roots may collectively warrant closer evaluation
- The MRI is targeting the head, jaw, or neck — this increases the likelihood of image artefacts near dental restorations
- You have experienced sensitivity or discomfort from your crown — whilst this is not directly related to MRI safety, it may indicate a need for a dental assessment before any elective procedures
- You have metal restorations that predate modern alloy standards — older materials may have different magnetic properties
In all these situations, a conversation with your dentist and your radiography team before the scan is the appropriate step. This does not mean refusing or delaying a medically necessary scan — always follow the guidance of your doctor — but being well-informed helps everyone involved make the best decisions for your care.
Clinical Background: Dental Alloys and Magnetic Properties
Understanding a little of the underlying science can help patients feel more informed and confident.
Magnetic susceptibility is a measure of how strongly a material responds to an applied magnetic field. Materials fall into three broad categories:
- Ferromagnetic — strongly attracted to magnets (e.g., iron, cobalt in some forms). These materials pose the most significant concerns in an MRI environment.
- Paramagnetic — weakly attracted to magnetic fields (e.g., some titanium alloys, platinum). The attraction is negligible in clinical MRI settings.
- Diamagnetic — very weakly repelled by magnetic fields (e.g., gold, copper). These are considered the safest in MRI environments.
Gold alloys — a common choice for posterior dental crowns — are largely diamagnetic and are well-documented as MRI-compatible in the scientific and radiological literature. Cobalt-chromium and nickel-chromium alloys, widely used in base metal crowns and porcelain-fused-to-metal restorations, are generally paramagnetic with low magnetic susceptibility values, and are similarly considered acceptable for MRI.
The small amount of heating that can theoretically occur due to radiofrequency energy is not considered clinically significant for dental crown-sized restorations based on current evidence and research. However, the science is nuanced, and your radiography team will always conduct the appropriate assessment for your individual situation.
Prevention and Oral Health Advice: Keeping Your Dental Records Updated
One of the most practical steps patients can take — entirely unrelated to MRI concerns — is to ensure that their dental records are kept up to date and accessible. This becomes particularly relevant when you need to share information with medical professionals ahead of a scan or surgical procedure.
Practical oral health and record-keeping tips:
- Attend regular dental check-ups — typically every six to twelve months, or as recommended by your dentist. Routine visits allow your dentist to document changes and restorations accurately.
- Keep a note of dental work — if you know you have had crowns, implants, or bridges placed, record the approximate date and ask your dentist to note the material used.
- Inform your dentist of medical procedures — if you are planning surgery or have been referred for an MRI, let your dental practice know. They may be able to provide relevant documentation to support your medical team.
- Report changes in your crown — sensitivity, a change in bite, or discomfort around a crowned tooth should be reviewed by your dentist promptly.
- Maintain good oral hygiene — crowns can fail at the margins if gum disease or decay is not adequately managed. Brushing twice daily with fluoride toothpaste, flossing, and attending hygiene appointments are important habits.
If you are considering a new crown or replacing an existing restoration, our team at Dental Clinic London can provide a thorough clinical assessment and discuss the most appropriate materials for your individual needs.
Key Points to Remember
- Most modern dental metal crowns are considered MRI-compatible, as they are typically made from non-ferromagnetic or weakly ferromagnetic alloys.
- Always inform your radiographer and dentist before undergoing an MRI if you have any dental crowns, bridges, or implants.
- The type of metal matters — gold alloys, cobalt-chromium, and nickel-chromium are the most common crown materials and are generally MRI-safe.
- Image artefacts may occur near dental metalwork but do not typically affect MRI scans of areas distant from the mouth.
- Older crowns may have uncertain compositions — check with your dental practice if you are unsure.
- Professional assessment is essential — general information is not a substitute for individual clinical evaluation by your dental or medical team.
Frequently Asked Questions
Will my metal dental crown cause pain during an MRI?
For the vast majority of patients with modern dental crowns, there is no pain during an MRI. Most dental alloys used in crowns today are non-ferromagnetic, meaning they are not significantly attracted to the magnetic field. There can be a very minor, transient warming sensation reported by some patients with larger metallic restorations, but this is generally not considered clinically significant. If you experience unexpected discomfort during an MRI, you should alert the radiographer immediately. Any pre-existing dental sensitivity should be discussed with your dentist separately before your scan.
Do I need to remove my dental crown before an MRI?
Dental crowns are permanent restorations cemented onto the prepared tooth. They are not removable by the patient and would not routinely be removed before an MRI. If your radiography team has any specific concerns about a particular restoration, they will discuss options with you before proceeding with the scan. In most cases, removal is neither necessary nor advisable. The focus should be on clear communication with your radiographer about what restorations you have and the materials involved.
Can a metal dental crown affect MRI image quality?
Yes, it is possible for metal dental crowns to create localised image artefacts — areas of distortion or signal loss — on MRI images near the crown. This is more likely to be relevant when the MRI is focused on the head, jaw, or neck area. For scans targeting other regions of the body, dental crown artefacts are unlikely to interfere with the diagnostic value of the images. Your radiologist will be aware of any potential artefacts and will factor them into their interpretation of the scan results.
Is there a difference between metal crowns and dental implants regarding MRI safety?
Yes, there is an important distinction. Dental implants are typically made from titanium, which is paramagnetic with a very low magnetic susceptibility, and they are generally considered MRI-safe. Metal crowns vary in their composition — gold alloys, base metal alloys, and stainless steel have different magnetic properties. Both implants and crowns should be declared on your MRI safety screening form. The fundamental principle is the same: inform your radiographer of all dental metalwork so that an appropriate assessment can be made before the scan proceeds.
Should I be concerned about older metal crowns and MRI?
Older crowns placed many years ago may have been fabricated from alloys that are less commonly used in modern dentistry, and their exact composition may not be readily available. This does not automatically make them unsafe for MRI, but it does mean that greater care in communication is warranted. Contact your dental practice and, if possible, obtain records of when the crown was placed and the material used. Share this information with your radiographer. If records are unavailable, your radiographer will assess the situation based on their professional training and experience.
What should I tell the MRI department about my dental work?
When completing your MRI safety screening questionnaire, declare all dental restorations — including crowns, bridges, implants, retained roots, and any orthodontic appliances. Specify that you have metal crowns and, if known, the approximate date of placement and material type. If you are uncertain about any details, say so. Your radiographer is trained to handle these situations and will guide you through the appropriate steps. It is always better to provide too much information than too little when it comes to MRI safety.
Conclusion
For most patients in London and across the UK, metal dental crowns are generally considered safe in MRI environments, thanks to the non-ferromagnetic or weakly ferromagnetic nature of the alloys most commonly used in modern dentistry. However, the answer is not the same for every patient, and individual circumstances — including the type of crown material, the age of the restoration, and the nature of the MRI scan — all play a role in determining the appropriate course of action.
The most important steps any patient can take are to communicate clearly with both their dental practice and their MRI radiography team, to declare all dental restorations on safety screening forms, and to ask questions if anything is unclear. Good communication between patients and healthcare professionals is at the heart of safe, effective care.
Whether you are preparing for an upcoming MRI, considering a new dental crown, or simply want to understand your current restorations better, speaking with a qualified dental professional is always the right starting point. Metal crowns and MRI safety is a topic that can feel complex, but with the right guidance and open communication, it need not be a source of unnecessary concern.
Disclaimer: This article is intended for general educational purposes only and does not constitute personalised dental advice. Individual diagnosis and treatment recommendations require a clinical examination by a qualified dental professional.
Dental symptoms and treatment options should always be assessed individually during a clinical examination.
Next Review Due: 24 August 2027
