Everything you need to know about dental crowns
What are crowns used for?
- Repairing a broken tooth or a tooth that has been worn down
- Repairing and covering a tooth that has been treated by a root canal
- Replacing a missing tooth as part of a bridge
- Replacing a missing tooth on a dental implant
- Covering discolored or poorly shaped teeth to improve aesthetic appearance
- Repairing or protecting a tooth that has large amount of decay, chips or cracks
- Closing minor gaps or fixing minor tooth alignment issues
COMMON TYPES OF CROWNS
Porcelain-fused-to-metal (PFM) Crowns
Porcelain-fused-to-metal (PFM) crowns can be color matched to your other teeth and are the most common type of crown used. PFM crowns are very strong, have a good appearance, and are very reasonably priced. They are most commonly recommended for rear teeth, as they have a good aesthetic appearance and the metal base provides a strong core that can withstand the pressure exerted on these teeth during chewing. However, in full natural light, the metal base can show through as a shadow in the tooth, especially for front teeth. Also, over time, if the gums recede from the crown, the metal base can be seen as a dark line that will show where the crown meets the gum.
- durability and price
- not recommended for patients with metal allergies
Full Porcelain/Ceramic Crowns
Full porcelain or full ceramic crowns provide the best natural appearance and are also an excellent choice for patients who have metal allergies. They are most commonly used for front teeth, as they have an excellent natural appearance. However, they are not as strong as PFM crowns, are more expensive, and can be prone to chipping or cracking. As such, they are not typically used for rear teeth.
- excellent natural appearance
- middle range pricing
- least durable material
- can be prone to chips or cracks
Zirconia crowns are the strongest crown available and also have an excellent natural appearance that is comparable to full porcelain or full ceramic crowns. They are also the most expensive. Zirconia crowns are virtually indestructible and can be used for front or rear teeth, but since they are so hard, they can wear on the other teeth. They can either be milled out of solid blocks of zirconia, or used as a strong, natural looking base fused to a porcelain veneer. Since zirconia crowns are so durable, they can me made much thinner than other crowns and require less removal of the tooth for placement.
- excellent natural appearance
- thinnest crowns available
- extremely durable
- high cost
- can wear on other teeth
Temporary crowns are usually an acrylic material that can be temporarily cemented onto the tooth while the permanent crowns are being prepared by the dental laboratory. The can be fitted immediately after preparation is done on the tooth for a permanent crown.
How long do crowns last?
Typically, crowns last for about 10-15 years, though many patients will have their crowns for a lifetime. Zirconia crowns or full gold/metal crown are the longest lasting. Crowns need to be replaced when they have chipped or broken, though most crown failures are caused by other issues such as decay of the tooth under the crown or by gum disease. Proper oral hygiene is important in maintaining crowns.
How long does it take for crowns to be finished?
Usually, crowns can be finished in about one week. You would need to visit twice; once at the beginning of the week, and once at the end of the week. During the interim time, the dental lab will be hard at work custom crafting your crowns. More time may be needed depending on if the clinic does not have their own lab, if there are many crowns to be done, if a complicated root canal procedure is involved, how busy the lab is, etc. It is important to schedule your appointment as far ahead as possible to ensure your treatment can be concluded during your stay.
What is the process for making crowns?
Crowns usually require three separate visits. During the first appointment, the dentist will examine the tooth, take x-rays to check for cavities and the structure of the tooth root. Following that, the tooth is prepared for the crown by filing down and reshaping the tooth. Local anesthetics are given during this portion of treatment. Then, the dentist will take impressions of the tooth which are then sent off to the dental laboratory, where the crowns are custom-crafted.
In most cases, the lab work can be done for a crown in about 5-7 days and then you would return to have the crown fitted. During this time you would have a temporary crown fitted.
After the lab has crafted the crowns, you would return for the second visit dental crown. The dentist will check the color and fit of the crown, make sure that it lines up correctly with your bite, and then if all is in order, permanently cement the crown into place.
Does it hurt to have teeth prepared for crowns?
Typically the tooth preparation can cause sensitivity and soreness, though some people experience no pain at all in having their teeth prepared for crowns. It really depends on the patient, how close to the surface of the tooth the nerve is, etc. Local anesthetics are given to numb the tooth during preparation.
Can crowns be made to match the surrounding teeth?
Absolutely! As part of the crown preparation process, the dentist will color-match your new crowns to the surrounding teeth so they blend in naturally. If you wish to have teeth whitening, this is done prior to color matching and preparing the crowns so that the crown will match your new, whiter smile.
Can my existing crowns be whitened?
Unfortunately crowns cannot be laser whitened. If your existing crowns are very old and discolored, they would need to be replaced with new crowns if you wish for an improved appearance.
What types of metal are used with porcelain fused to metal (PFM) crowns?
All types of alloys are used. Porcelain can be fused to a standard alloy base which can be comprised of metals such as nickel or chromium, or they can be fused to precious metals such as platinum, silver, or gold. The precious metals cost more than standard alloys.
This article is meant for information purposes only and is not intended to be dental advice or instructions for dental diagnosis or treatment. Please consult with your dentist or a qualified dental professional before starting or changing dental treatment