A PFM crown, or porcelain-fused-to-metal crown, is a type of dental crown made with a metal framework covered by tooth-coloured porcelain. It has been used for many years to restore teeth that are weakened, damaged, heavily filled, or treated with a root canal.
PFM crowns combine the strength of a metal substructure with the appearance of porcelain on the visible surface. However, they also have some limitations, particularly when aesthetics and the appearance of the gum line are major concerns.
This guide explains what a PFM crown is, its benefits and disadvantages, how the procedure works, how long it may last, and what can affect its cost.
PFM stands for porcelain-fused-to-metal. A PFM crown consists of a metal framework that provides structural support and a layer of dental porcelain that covers the visible part of the crown.
The metal provides strength, while the porcelain is shaped and coloured to resemble a natural tooth.
PFM crowns can be used to restore individual teeth and may be considered for both front and back teeth depending on the patient’s dental condition, bite, aesthetic requirements, and the amount of remaining tooth structure.
What Is a PFM Crown Made Of?
A PFM crown has two main components:
Metal framework
The inner portion of the crown is made from a dental metal alloy. It provides the underlying structure and helps the crown withstand normal chewing forces.
Porcelain layer
Dental porcelain is bonded to the metal framework. The porcelain is designed to resemble natural tooth enamel in colour and shape.
The combination gives PFM crowns their characteristic appearance and structure.
When Is a PFM Crown Recommended?
A dentist may consider a PFM crown when a tooth requires substantial restoration and a crown is appropriate.
Situations may include:
- A tooth that has been significantly weakened by decay
- A tooth with a large existing filling
- A tooth that has undergone root canal treatment
- A cracked or damaged tooth that requires full-coverage restoration
- A tooth that needs restoration after significant structural loss
- Certain situations where a durable full-coverage crown is required
The appropriate crown material depends on the individual tooth and factors such as its location, remaining tooth structure, bite, aesthetic expectations, and oral health.
Benefits of PFM Crowns
PFM crowns have been used extensively in restorative dentistry and offer several potential benefits.
1. Good strength
The metal framework provides structural support to the crown. This can make PFM crowns suitable for teeth exposed to substantial chewing forces in selected cases.
2. Tooth-coloured appearance
The porcelain outer layer can be matched to the colour of the surrounding teeth, giving the restoration a more natural appearance than a completely metal crown.
3. Established restorative option
PFM crowns have been used in dentistry for decades. Their long history of clinical use means dentists are familiar with their preparation, fabrication, and placement.
4. Suitable for different teeth
Depending on the individual case, PFM crowns can be used on both anterior and posterior teeth.
However, the aesthetic demands and biting forces differ between front and back teeth, so crown selection should be based on a dental examination.
5. Can restore significantly damaged teeth
When a tooth has lost substantial structure, a full crown may help restore its shape and function when the tooth is otherwise suitable for restoration.
Disadvantages of PFM Crowns
PFM crowns also have limitations that should be considered before treatment.
1. Metal is present underneath the porcelain
Unlike metal-free ceramic crowns, PFM crowns contain a metal framework. Although it is covered by porcelain, the underlying metal can sometimes become visible around the gum line.
2. Gum-line aesthetics may change over time
If the gum recedes, the edge of the metal framework may become more noticeable. This can be a concern when the crown is placed on a highly visible front tooth.
3. Porcelain can chip
The porcelain covering can chip or fracture under certain circumstances. The risk can depend on factors such as biting forces, crown design, tooth position, and habits such as teeth grinding.
4. More tooth preparation may be required
Creating enough space for both the metal framework and porcelain may require removal of some tooth structure. The amount of preparation depends on the tooth and the design of the restoration.
5. Appearance may differ from natural teeth
Although PFM crowns can provide a tooth-coloured appearance, the optical properties of porcelain over metal may not replicate natural enamel as closely as some modern all-ceramic restorations.
PFM Crown Procedure: What to Expect
Getting a PFM crown generally involves several stages.
1. Dental examination
The dentist first examines the tooth and surrounding tissues. X-rays or other diagnostic tests may be recommended depending on the condition of the tooth.
If the tooth has an active infection, extensive decay, or insufficient supporting structure, additional treatment may be necessary before a crown is placed.
2. Tooth preparation
The tooth is reshaped to create the space required for the PFM crown.
The dentist removes damaged or decayed tooth structure where necessary and prepares the tooth so the crown can fit securely.
3. Impression or digital scan
An impression or digital scan of the prepared tooth and surrounding teeth is taken.
This information is used to create a crown that fits the prepared tooth and works with the patient’s bite.
4. Temporary crown
A temporary crown may be placed while the permanent PFM crown is being fabricated.
It protects the prepared tooth and allows normal function during this period.
5. Trial and adjustment
Once the permanent crown is ready, the dentist checks its fit, shape, colour, contacts with neighbouring teeth, and bite.
Adjustments can be made if required.
6. Permanent cementation
After the dentist is satisfied with the fit and function, the PFM crown is permanently cemented onto the tooth.
How Long Does a PFM Crown Last?
The lifespan of a PFM crown varies from person to person. It depends on factors such as:
- Oral hygiene
- Bite forces
- Teeth grinding or clenching
- Condition of the supporting tooth
- Crown fit and design
- Gum health
- Regular dental care
- Diet and oral habits
A well-maintained crown can function for many years, but no dental crown is considered permanent. Regular dental examinations allow the dentist to check the crown and the tooth underneath it.
PFM Crown vs Zirconia Crown
Both PFM and zirconia crowns can be used for dental restoration, but they are made differently.
A PFM crown has a metal framework covered with porcelain, while zirconia crowns are made from zirconia ceramic.
The choice between them depends on factors such as:
- Location of the tooth
- Strength requirements
- Aesthetic expectations
- Gum-line visibility
- Available space
- Bite and chewing forces
- Remaining tooth structure
- Individual treatment requirements
There is no single crown material that is appropriate for every patient.
For a detailed comparison, see our guide to PFM vs zirconia crowns.
How to Care for a PFM Crown
A crowned tooth still needs regular oral care. The crown covers the visible portion of the tooth, but the surrounding gum and the tooth underneath remain susceptible to dental problems.
To care for your PFM crown:
- Brush twice a day with fluoride toothpaste.
- Clean between your teeth every day.
- Avoid using your teeth to open packages or bite hard objects.
- Follow your dentist’s recommendations if you grind or clench your teeth.
- Attend regular dental check-ups.
- Report persistent sensitivity, pain, looseness, or changes around the crown to your dentist.
Can a PFM Crown Get Cavities?
The crown itself cannot develop a cavity because it is made from dental materials. However, the natural tooth underneath or around the crown can still develop decay.
This is why brushing, interdental cleaning, and regular dental examinations remain important after getting a crown.
Can a PFM Crown Break?
A PFM crown is designed to withstand normal chewing forces, but it can still become damaged.
The porcelain layer may chip or fracture, particularly when the crown is exposed to excessive forces. Teeth grinding, trauma, and biting hard objects can increase the stress placed on a crown.
If your PFM crown becomes chipped, cracked, loose, or painful, consult your dentist rather than attempting to repair it yourself.
Are PFM Crowns Suitable for Front Teeth?
PFM crowns can be used on front teeth in selected cases. However, front teeth have greater aesthetic requirements because they are highly visible when smiling.
The dentist may consider factors such as the patient’s desired appearance, gum-line visibility, remaining tooth structure, and available crown options before recommending a material.
Frequently Asked Questions About PFM Crowns
Is a PFM crown good?
A PFM crown can be an effective option for restoring certain damaged or weakened teeth. Whether it is suitable depends on the condition and location of the tooth, bite, aesthetic requirements, and other individual factors.
What does PFM stand for in dentistry?
PFM stands for porcelain-fused-to-metal. The crown has a metal framework with a porcelain layer bonded over it.
Are PFM crowns permanent?
No dental crown is permanent. A PFM crown can last for many years with appropriate care, but its lifespan varies depending on oral hygiene, bite forces, crown condition, and the health of the underlying tooth.
Can PFM crowns be used after a root canal?
Yes. A PFM crown may be considered for a tooth that has undergone root canal treatment when the tooth requires full-coverage restoration and is suitable for a crown.
Are PFM crowns metal-free?
No. PFM crowns contain a metal framework underneath the porcelain.
Which is better, PFM or zirconia?
PFM and zirconia have different material properties and aesthetic characteristics. The appropriate option depends on the tooth, bite, aesthetic requirements, remaining tooth structure, and other clinical considerations.
How do I know if I need a PFM crown?
A dentist needs to examine the tooth to determine whether a crown is required and which material is appropriate. The decision may depend on the amount of remaining tooth structure, previous dental treatment, tooth location, bite, and aesthetic requirements.
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