Introduction
If you have a dental crown and have been referred for an MRI scan, it is completely natural to feel concerned. Many patients in London and across the UK search online asking whether metal crowns are safe in MRI machines — and it is one of the most common dental questions asked ahead of medical imaging appointments.
Understanding what your dental crown is made from, how MRI technology works, and what precautions are typically taken can help to put your mind at ease before your scan. Metal dental crowns have been used reliably in dentistry for many decades, and the relationship between metal restorations and MRI safety is well understood by both medical and dental professionals.
This article explains the dental and clinical background behind this question, discusses the different types of metal used in crowns, outlines what typically happens ahead of an MRI, and helps you understand when speaking with your dentist or the imaging team in advance may be advisable.
Featured Snippet: Are Metal Crowns Safe in an MRI?
Are metal crowns safe in an MRI scan?
In most cases, metal dental crowns are considered safe during an MRI scan. The metals commonly used in dental crowns — such as gold alloys, cobalt-chromium, and nickel-chromium — are generally non-ferromagnetic, meaning they are not strongly attracted by the magnetic field. However, they may cause localised image artefacts, and individual suitability should always be confirmed with the imaging team prior to your scan.
What Is a Metal Dental Crown?
A dental crown is a tooth-shaped restoration placed over a prepared natural tooth to restore its shape, strength, and function. Crowns can be made from a variety of materials, including porcelain, ceramic, zirconia, and metal alloys — or a combination of these, such as porcelain-fused-to-metal (PFM) crowns.
Metal crowns are typically made from alloys that may include:
- Gold alloys — a traditional and durable option
- Cobalt-chromium — commonly used for back teeth where strength is needed
- Nickel-chromium — another base metal alloy used in restorative dentistry
- Palladium alloys — less commonly used today
Each alloy has different physical properties, including varying responses to magnetic fields. Metal crowns are generally chosen for their longevity and strength, particularly for posterior teeth that experience high biting forces. Understanding which material your crown is made from is an important first step when considering any MRI-related concerns.
If you are unsure what material your dental crown contains, your dentist can review your clinical records and provide this information before your imaging appointment.
How Does an MRI Machine Work?
Magnetic Resonance Imaging (MRI) uses a powerful magnetic field combined with radiofrequency waves to produce detailed images of soft tissues, organs, and structures within the body. Unlike X-rays, MRI does not involve ionising radiation, making it a commonly used diagnostic imaging tool in medical practice.
The core concern with MRI and metal relates to the concept of ferromagnetism — the degree to which a metal is attracted to a strong magnetic field. Strongly ferromagnetic metals can move, heat up, or interfere with the scan when placed inside an MRI machine. This is why objects such as surgical implants, pacemakers, and certain metal clips require careful screening before a scan.
Dental metals, however, are generally categorised as non-ferromagnetic or weakly ferromagnetic, meaning they do not respond to the magnetic field in the same way. This is why most dental restorations — including metal crowns — are generally considered MRI-compatible, though they may cause localised image distortion in the area immediately surrounding the crown.
The strength of modern MRI machines is measured in Tesla units (T). Most clinical MRI scanners operate at 1.5T or 3T, and dental metal compatibility assessments are generally based on these field strengths.
Are Metal Crowns Ferromagnetic?
The key safety consideration in MRI imaging is whether a material is ferromagnetic — strongly attracted to a magnet. The metals most commonly used in dental crowns are, in the majority of cases, non-ferromagnetic or only mildly paramagnetic, which places them in a lower-risk category for MRI safety.
Common dental crown alloys and their typical MRI profiles:
- Gold alloys — considered non-ferromagnetic; widely regarded as MRI-safe
- Cobalt-chromium — generally non-ferromagnetic; commonly assessed as MRI-compatible
- Nickel-chromium — typically non-ferromagnetic; usually considered MRI-compatible
- Stainless steel — used more commonly in paediatric dentistry; may have mild ferromagnetic properties but is generally considered acceptable for dental use in MRI contexts
It is important to note that the exact alloy composition can vary between manufacturers and dental laboratories. This is why the MRI imaging team will always conduct a thorough pre-scan safety questionnaire, and why it is advisable to inform the radiographer of any dental work prior to your scan.
If your dentist or treating clinician has placed a dental crown, they should have documentation of the specific alloy used, which can be shared with the MRI team if required.
What About Image Artefacts?
Even when a metal dental crown is confirmed as safe for MRI, it is important to understand that metal restorations can cause image artefacts — areas of distortion or signal dropout on the MRI image. This occurs because metal alters the local magnetic field, which affects how the MRI signal is generated and recorded in the surrounding tissue.
Image artefacts from dental crowns are typically localised, affecting only the area immediately around the crown. In most cases, this does not compromise the diagnostic quality of the wider scan unless the area of clinical interest is very close to the jaw or oral cavity.
For example:
- A patient having an MRI of the knee or abdomen is unlikely to be clinically affected by artefacts from a dental crown
- A patient having an MRI of the head, neck, or jaw may experience some degree of artefact in the local region
The radiologist and radiographer will be aware of this possibility and can adapt imaging protocols where necessary. Informing the team of your dental crown before the scan allows them to make appropriate adjustments and ensure the most diagnostic image quality possible.
Clinical Dental Science: Why Crown Material Matters
Understanding why different dental crown materials behave differently in an MRI environment requires a basic understanding of materials science and atomic structure. Metals can be classified by how their electrons respond to external magnetic fields:
- Diamagnetic materials (e.g. gold) — very weakly repelled by magnetic fields; extremely low risk
- Paramagnetic materials — weakly attracted to magnetic fields; generally considered safe in clinical MRI
- Ferromagnetic materials (e.g. iron, nickel in certain forms) — strongly attracted to magnetic fields; higher risk
Dental alloys are specifically engineered for their clinical performance — including biocompatibility, durability, and corrosion resistance. As a result, the metals used in most modern dental crowns have a deliberately low ferromagnetic profile. This is a different composition to the types of metals that cause significant MRI safety concerns, such as certain vascular clips or older surgical implants.
Your dental crown sits within the oral cavity and is bonded to the underlying tooth structure. Unlike implanted medical devices positioned near critical structures such as blood vessels or nerves, the physical positioning of a dental crown means that even in cases where mild paramagnetic properties exist, the clinical risk profile is typically low.
That said, if you have multiple metal restorations, bridges, or other dental devices, it is always advisable to discuss your full dental history with the MRI team. You can also ask your dentist about dental crowns and restoration options to understand what material your current crown contains.
What Happens During the Pre-MRI Safety Check?
Before any MRI scan in the UK, patients are required to complete a comprehensive pre-scan safety screening questionnaire. This is a standard and essential part of the imaging process, conducted by radiographers who are trained in MRI safety protocols.
This questionnaire typically asks about:
- Any surgical implants (joint replacements, cardiac devices, vascular clips)
- Orthodontic appliances (braces, retainers)
- Dental work — including crowns, bridges, implants, and dentures
- History of metal fragments or injuries
- Any implanted electronic devices
When it comes to dental crowns specifically, you should:
- Inform the radiographer that you have a metal crown and identify which tooth it is on
- Provide the material information if available — your dental practice can help supply this
- Answer all screening questions honestly and completely — this allows the team to make an informed safety assessment
In the vast majority of cases, patients with metal dental crowns proceed with their MRI scan without any issue. Removable dental appliances (such as dentures or retainers) are typically asked to be removed before entering the scan room, as standard practice.
When Should You Speak to Your Dentist Before an MRI?
For most patients with a single metal dental crown, a pre-scan conversation with the MRI team via the safety screening process is sufficient. However, there are certain circumstances where it may be advisable to consult your dentist in advance of an MRI appointment:
- You are unsure what material your crown is made from — your dentist can review your records and provide the relevant information
- You have multiple metal restorations or a dental bridge — more extensive metalwork may warrant a clearer material summary
- You have dental implants — titanium implants are generally considered MRI-safe, but confirmation from your dental team is reassuring
- You have been fitted with a less common restorative device — some specialist restorations may use different metal compositions
If you are planning to undergo routine dental treatment and are also anticipating an MRI in the near future, discussing crown material options with your dentist before treatment begins is a sensible step. Modern ceramic and zirconia crown options are entirely MRI-compatible and produce no image artefacts, which may be relevant depending on your individual medical circumstances.
For those exploring restorative options, it may be worth asking about tooth-coloured crown alternatives that avoid metal entirely.
Prevention and Oral Health Considerations
Whether your dental crown is made from metal, ceramic, or a combination of materials, maintaining good oral health around the restored tooth remains important. A well-maintained crown can last many years, but the underlying tooth and surrounding gum tissue still require attentive care.
Practical oral health advice for patients with dental crowns:
- Brush twice daily using a fluoride toothpaste, paying careful attention to the gum line around the crown
- Floss or use interdental brushes daily — the margin where the crown meets the tooth can be a site for plaque accumulation
- Attend regular dental check-ups — your dentist will monitor the condition and fit of the crown over time
- Avoid excessive biting forces on hard foods or objects — this applies to all crown types
- Report any changes in sensation, fit, or appearance of the crown promptly
Maintaining the health of the tooth beneath the crown is particularly important, as decay can still occur at the crown margin. If you notice any sensitivity, looseness, or discomfort around a crowned tooth, arranging a dental review is advisable.
Good general oral health also supports your broader wellbeing, and staying up to date with routine dental examinations ensures that any emerging issues can be identified and managed early.
Key Points to Remember
- Metal dental crowns are generally considered safe in MRI scans, as the alloys used are typically non-ferromagnetic or only mildly paramagnetic
- Always inform the MRI team about any dental metalwork before your scan — this is part of standard pre-scan safety screening
- Metal crowns may cause localised image artefacts, but this rarely affects the diagnostic quality of scans distant from the oral cavity
- Your dentist can provide material information about your crown if you are unsure what alloy was used
- Ceramic and zirconia crowns are metal-free alternatives that produce no MRI artefacts and may be discussed with your dentist if relevant to your circumstances
- Regular dental maintenance of crowned teeth helps preserve both the restoration and the underlying tooth structure
Frequently Asked Questions
Can I have an MRI scan if I have a metal dental crown?
In most cases, yes. The metals used in dental crowns are typically non-ferromagnetic, meaning they are not strongly attracted to the MRI magnetic field and are generally considered safe. You should always inform the radiographer about your dental crown during the pre-scan safety screening process. They will assess your individual situation and can advise accordingly. In the vast majority of cases, patients with metal dental crowns proceed with their scan without any difficulty.
Will my metal crown heat up during an MRI?
Heating is a concern associated with some metal implants in MRI environments, but for small dental restorations such as crowns, the risk of clinically significant heating is considered very low. The metals used in dental crown alloys are generally assessed as MRI-compatible at standard clinical field strengths of 1.5T and 3T. The pre-scan safety team will factor this into their assessment based on the specifics of your restoration.
Do I need to remove my dental crown before an MRI?
No — dental crowns are cemented or bonded to the prepared tooth and cannot be removed like a denture or retainer. The MRI team is aware of this and will assess the safety of your fixed dental work accordingly. Removable dental appliances such as full or partial dentures and orthodontic retainers are typically asked to be removed before entering the scan room, as this is straightforward and reduces unnecessary metallic content in the imaging field.
Does having a metal crown affect the quality of my MRI images?
Metal dental crowns can cause localised image artefacts — areas of distortion on the scan — in the immediate vicinity of the crown. For most MRI scans that focus on other parts of the body, this is clinically insignificant. If your MRI is of the head, neck, or jaw area, the radiographer and radiologist will be aware of this possibility and can adapt imaging protocols to minimise the impact. Always inform the imaging team of your dental history so they can optimise the process.
Are porcelain or ceramic crowns safer than metal crowns for MRI?
All-ceramic, all-porcelain, and zirconia crowns contain no metal and therefore produce no image artefacts during an MRI scan. They are fully MRI-compatible in the clearest sense. However, this does not mean that metal crowns are unsafe — most metal dental alloys are considered safe in MRI environments. If you are considering a new crown and have specific medical circumstances that make MRI compatibility a priority, this is worth discussing with your dentist as part of your treatment planning conversation.
Should I tell my dentist I need an MRI before getting a crown fitted?
If you know you will be having an MRI scan in the near future, it is worth mentioning this to your dentist before any restorative treatment begins. Your dentist can discuss material options with you and ensure that appropriate records of the alloy used are kept. This information can then be provided to the MRI team if required, making the pre-scan process more straightforward.
Conclusion
For most patients, having a metal dental crown does not present a significant obstacle to undergoing an MRI scan. The alloys most commonly used in dental crowns are generally non-ferromagnetic and are widely considered compatible with clinical MRI environments. The standard pre-scan safety screening process is designed to identify and manage any concerns, and informing the radiographer of your dental work is all that is typically required.
That said, every patient's situation is individual. The specific alloy composition of your crown, the type of MRI being performed, and any additional dental restorations you may have can all be relevant factors. Contacting your dental practice for material information and discussing any concerns with the MRI team ahead of your appointment is always a sensible approach.
If you are considering dental crown treatment and wish to understand your material options — including metal-free alternatives — speaking with a qualified dental professional is a recommended first step. Dental symptoms and treatment options should always be assessed individually during a clinical examination.
Disclaimer: This article is for general educational information only and is not personalised dental advice. Diagnosis and treatment recommendations require a clinical examination by a qualified dental professional.
Cosmetic Dentistry Clinic
Cosmetic Dental Team at Cosmetic Dentistry Clinic
With years of experience in cosmetic and restorative dentistry, Cosmetic is dedicated to helping patients achieve their perfect smile through personalised care and cutting-edge techniques.
