When getting dental restorations, one of the options you may have is a porcelain-fused-to-metal (PFM) crown. Here’s a closer look at these dental crowns and why they could be the right choice for you.
What Are Porcelain-Fused-to-Metal Crowns and How Do They Work?
Porcelain fused to metal crowns are dental restorations that combine a metal alloy substructure to provide strength and a porcelain exterior to recreate the tooth’s anatomy. This porcelain layer matches your exact natural tooth color.
PFM crowns have an inner metal coping thickness of between 0.3 mm and 0.5 mm, with a layer that allows for better bonding. Above that are layers of porcelain that take on the exact contours and translucency of your teeth. The porcelain thickness tends to be between 1.5 mm and 2.0 mm.
There are clinical considerations PFM crowns require to ensure that they are the right match. PFM restorations are well-suited for back teeth because they can withstand a significant amount of bite force. They are also ideal for dental bridges and implant crowns that need resistance.
Porcelain fused to metal crowns offer long-term durability with a few trade-offs. They are not as translucent as other options, and the porcelain can chip if subjected to excess force. It’s possible for the metal edge of the crown to become visible as well, darkening your gum line. For some people, metal allergies could be a concern.
Overall, though, PFM crowns are a durable, natural-looking choice for a wide variety of situations.
How Do PFMs Compare to All-Ceramic and Full Metal Crowns?
PFM dental crowns are different from options made completely of ceramic. All-ceramic crowns, such as those made of lithium disilicate or zirconia, bring maximum aesthetics to the table. They look just like your natural teeth and provide high translucency, making them ideal for front teeth.
Zirconia, in particular, is an especially strong material. These crowns require less tooth reduction during preparation.
Full metal crowns readily take on wear and tear, making them perfect for molars. They are not the best option if you’re looking for natural aesthetics, however, because they don’t blend in with your teeth.
When considering PFM vs. zirconia, keep in mind that PFM restorations tend to be less costly. The same is true of PFM vs. E.max (lithium disilicate). If your main concern is durability and strength, full metal options are at the top of the list, followed closely by monolithic zirconia and lithium silicate.
A PFM crown gets its strength from the combination of its metal and ceramic layers. These crowns may still not be strong enough for people with bruxism or heavy occlusal loads, though.
The process of preparing the tooth for the restoration also varies when it comes to PFM crowns. You will typically need a more significant reduction because your dentist needs to make room for both the metal and porcelain layers.
Who Is a Good Candidate for a PFM Crown?
PFM crowns benefit a wide variety of needs and indications. Contraindications for PFM crowns generally involve sensitivity and oral health issues.
Often, they are best suited for back teeth subjected to high levels of force, as well as teeth with large coronal breakdown and extensive amalgam or composite material that require full coverage.
One of the toughest decisions is PFM vs. zirconia because of the strength that both options provide. Your aesthetic expectations are key here. If your focus is more on cost and strength, PFM crowns can make more sense. You should also have enough space to accommodate both metal and porcelain layers.
People with active bruxism or malocclusion could get more out of all-metal or zirconia crowns, but they may be able to adjust to benefit from PFM crowns if they use a nightguard.
There are some people who may not be good candidates for PFM crowns, however. Those who have advanced gum disease or sensitivities to metals will not benefit from this option. The same is true for people who have insufficient tooth structure to support this type of fused crown.
How Do You Plan Treatment for PFM Dental Restorations?
To make sure that PFM crowns are the right choice for you, your dentist will perform some vital assessments. When it comes to the indications/contraindications PFM crowns have, your dentist will look at your full medical and dental history. You may need an intraoral scan and periapical and bitewing radiographs.
Your periodontal biotype is another of the clinical considerations PFM crowns require. The thickness of your gums is particularly important because of the amount of space needed during tooth preparation PFM procedures.
If there are bite issues that need to be resolved, that should take place before the fabrication and placement of the crown. The next step will be to decide on the shade of the crown and the margin design. Depending on the tooth position, your dentist will choose either a shoulder or chamfer finishing line. The metal coping thickness will impact this choice, too.
Speaking with your provider can help you decide whether a computer-aided design/computer-aided manufacturing (CAD/CAM) PFM or one done at a dental laboratory is the better option for you. The decision can come down to cost as well as laboratory workflows, since that can affect how long the fabrication of the crown will take.
What Materials Are Used for PFM Crowns?
Whether you’re choosing quick CAD/CAM PFM options or those made at a dental laboratory, you need to know what types of materials the restorations will be made of. First, there are the options for the metal substructure. These include:
- High-noble alloys like gold and palladium
- Noble palladium-based alloys
- Base metal alloys like nickel‑chromium, cobalt‑chromium, and titanium
To decide on the right option for you, your dentist will look at your allergy history, the cost, and the strength that the metal needs to have, which will depend on whether it will go on a front or back tooth. Additionally, keep in mind that metal experiences thermal expansion, so the metal coping thickness and the resulting expansion must work with the porcelain thickness you need.
There are different porcelain systems to keep in mind, too. The traditional option is feldspathic porcelains, which are made of quartz, kaolin, and feldspar. These are highly translucent and effectively mimic natural teeth.
You also have the option of leucite‑ or lithium‑reinforced porcelains, which can withstand high stress. Leucite provides higher translucency, while lithium offers superior strength.
Aside from the porcelain itself, your dentist will also consider its application. They may need to decide between layering or powder/liquid buildup. The required thickness, as well as laboratory workflows, can dictate which option is the most effective one.
The type of manufacturing option for the crown will dictate the process. You will need intraoral scans or model scans. There will also be quality control checkpoints that will help your provider check the PFM crown’s fit, color, and margins.
What Is the Expected Longevity of PFMs and What Affects Survival?
PFM restorations are durable. The five-year survival rate is more than 90%, and the 10-year survival rate is often between 75% and 90%. The average reported lifespan for these crowns is between 10 and 15 years, but certain factors could impact that number.
Inappropriate porcelain crown maintenance can cause issues with the margins or even chipping. The metal structure is typically the sturdiest part of the crown, but it can still be a problem if it is placed under significant pressure. It can fracture along with the porcelain.
Some damage can be fixed, including minor porcelain chips or cement loss. Others, like extensive crown fractures or recurrent decay, will typically call for a crown replacement.
Oral hygiene issues can also impact how long the crowns last. Decay can still occur, putting the tooth at risk of structural damage. This can cause the crown to fall out.
People who have bruxism, which involves grinding the teeth at night or even during the day, can have a harder time maintaining intact crowns. The same is true for people with malocclusion.
This can significantly shorten the crown’s lifespan.
Preventing PFM Crown Damage
To help prevent these problems, it’s important to pay particular attention to your oral hygiene. Flossing every day and brushing your teeth twice a day with fluoride toothpaste can help prevent bacteria from settling and causing issues to the underlying structures that could put the restoration at risk.
If you grind your teeth at night, nightguards are an excellent option. Understanding what may be leading you to experience bruxism can also help you avoid daytime clenching.
You should schedule check-ups with your dentist every six to 12 months to ensure that the crown’s margins are intact and that there are no cracks. If there are chips, getting fast repairs can help protect the crown and prevent bacteria from making their way to your tooth.
How Much Do PFMs Cost and What Are Typical Financing Options?
The national price average for a PFM crown is between $600 and $1,000 per tooth. That significant price variation comes down to a variety of factors, including the local market. Case complexity can drive costs up, too.
A PFM crown’s cost includes the materials, which are the metal coping and the porcelain veneer. It will also cover the laboratory fees, which address custom glazing and shading, and various other services. Clinical preparation, such as cementation, is also covered by the cost.
A number of dental insurance plans cover 50% to 80% of crown costs after your deductible. It’s vital to look at your exact plan to see how much coverage you can receive.
Aside from insurance, you could have access to other types of payment options. You can use Flexible Spending Account or Health Savings Account funds, or in-office, interest-free payment plans. It’s also possible to turn to third-party medical lenders, but you can expect to pay interest on these types of loans. You may also have waiting periods.
Porcelain Fused to Metal (PFM) FAQs
Porcelain-fused-to-metal crowns offer the chance to get the strength of metal substructures with the natural beauty of porcelain. A PFM crown is a good option for back teeth that experience a significant amount of bite force.
When considering PFM vs. E.max, same-day CEREC crowns, and other similar options, keep in mind that porcelain fused to metal is likely not going to be as strong as zirconia or lithium disilicate, but it will typically be more affordable.
Get the answers you need to your most pressing questions regarding these types of crowns.
1. Can PFMs Cause Metal Allergies?
Yes, it’s possible for PFM crowns to cause metal allergies in very sensitive people. Typically, your dentist will carefully test whether you have these issues before even deciding on the right crown material. If you do have an allergic reaction to the metal alloy, you may be able to choose all-ceramic or zirconia restorations.
Symptoms to watch for include burning, redness, swelling, a metallic taste, and persistent oral redness.
2. Are PFMs Safe During MRI Scans?
MRIs are generally not a problem for people who have PFM crowns, but it may depend on the kind of metal used and where in the mouth the crown is located. In some instances, the PFM crown may cause distortions in the images, obscuring nearby structures.
You will likely not feel any heat or displacement when you have an MRI, but you may want to ask your dentist questions about your specific situation. You should also let the MRI team know that you have these kinds of crowns.
3. Can You Whiten a PFM Crown?
No, you can’t whiten a PFM crown with bleaching agents that you would use for your natural teeth. They will not affect porcelain. Polishing will only remove surface stains, but not color issues on other layers of the veneer. You may be able to rely on professional surface polishing services or reglazing.
4. Can a Chipped PFM Be Repaired Chairside?
Small chips and surface issues could be repaired at the office. Larger fractures, margin issues, and other serious restoration failures will usually need lab repair or replacement. Your dentist will give you a better idea of whether it’s possible to repair the issue or rely on a full crown replacement.
5. Will PFMs Increase Temperature Sensitivity?
PFM crowns can increase sensitivity, especially in the days following their placement. This will usually subside by the second week.
If you want to learn more about crowns and which dental restoration is best for your smile, schedule a consultation with Dr. Brett Langston today to explore your options and get personalized guidance.
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