Dental crowns are a dental restoration that completely covers and protects a tooth or a dental implant. Dental crowns are often necessary when extensive tooth decay or trauma has destroyed a large portion of the natural tooth structure, leaving it easily fracturable. Crowns will restore its strength, shape and improve its esthetic appearance. Dental crowns are typically bonded to the tooth using specialized dental cement (in dental implants, they are sometimes screwed in place). Your dentist can fabricate crowns from many different types of materials.
Types Of Dental Crowns
Your dentist can fabricate permanent dental crowns from stainless steel, all-metal (such as gold or another alloy), porcelain-fused-to-metal (also called a PFM crown), all resin, or all-porcelain.
-Stainless steel. These short-term use dental crowns are pre-formed metal shells. They are used on permanent or primary teeth, generally for just a few years or as a temporary dental crown. The temporary crown protects the tooth or filling, while a permanent crown is made from a more durable, cosmetic material. For children’s teeth, a stainless steel crown is commonly used to fit over a tooth that’s been prepared to fit it. The crown covers the entire tooth and protects it from further breakdown. Stainless Steel crowns also serve another purpose, to hold space in the mouth for the permanent teeth as they erupt into the mouth. When the primary tooth is eventually lost, the crown comes out with it.
-Metal Alloy. These dental crowns can include crowns fabricated using gold, other precious alloys (for example, platinum, palladium), or a base-metal alloy or non-precious (nickel or chromium). Pure gold is the softest yet easiest to get an ideal fit, while non-precious crowns are variable in hardness and strength.
Non-precious dental crowns tend to make the underlying tooth black. Over time, metals will leach into the tooth. Metal dental crowns can be made extremely thin. This allows for minimal tooth structure to be removed in preparation for the dental crown. Another advantage is that metal crowns are not as hard as porcelain. This “softness” causes much less wear on the opposing tooth. Metal dental crowns do not break or chip and tend to withstand biting forces very well over time. However, metal crowns are not very cosmetic, can eventually wear through, and generally are reserved for the areas not visible in a patient’s smile.
-Porcelain-fused-to-metal (PFM). These dental crowns are the most commonly used. They have the benefit of excellent fit and underlying strength from the metal. The underlying metal may be any combination of precious or non-precious, as mentioned above. These dental crowns are more cosmetic than all-metal crowns and are custom-fabricated to match the color of the surrounding teeth. However, the porcelain outer layer will be more abrasive, causing increased wear to the opposing teeth than a metal crown.
The porcelain outer portion of the crown can also break or chip over time. PFM dental crowns can be highly cosmetic and look just like your natural teeth when appropriately prepared. Over time, with gum recession, a dark line may become visible at the gumline. This is the underlying metal of the crown. Depending upon where it is in the mouth, it may become a cosmetic problem. These dental crowns can be used for any teeth in the mouth.
-All ceramic, all-porcelain, all resin. These dental crowns are the ultimate in cosmetic crowns. These will provide a better natural color match than any other crown type. All-porcelain crowns are also a good choice for patients with metal allergies. However, some are not as strong (example, Belle Glass) as porcelain-fused-to-metal crowns. Some are stronger (for example, Bruxzir crowns). Discuss with your dentist if they are right for your smile.
These dental crowns tend to wear down opposing teeth more than metal crowns would. Because of the lack of metal, there will never be a black line to worry about. All-porcelain crowns are the perfect choice for cosmetics or any teeth that will be easily seen when smiling.
Dental Crown Tips
So, you have been told you need a dental crown to restore a tooth?
The following are some questions to ask to ensure you are receiving the highest quality dental care that will last for a lifetime of smiles:
-Made In U.S.A.? Many dentists choose to save costs by using dental laboratories overseas in places like Costa Rica and China. They tend to be fabricated with inexpensive dental materials and lower-quality recycled dental metals and porcelain. Ask your dentist if your crown is being fabricated in an inferior dental laboratory. Also, ask to see the laboratory slip to tell how much gold content or type of porcelain is being used.
–How long should a dental crown last? Is there any warranty for breakage? Dental crowns generally last between 10-15 years with proper maintenance of oral hygiene. If a dental crown is made with inferior materials, you can expect a breakdown in half that time, if not sooner. Some dental labs will warranty a crown for up to one year. Especially important if you have chosen an all-porcelain dental crown.
–Lab-Created Provisional Crowns. Sometimes to help you make decisions, especially in a cosmetic area, a dentist may have temporary crowns fabricated by a dental laboratory. This type of dental crown is generally fabricated if there is healing needed before the final processing of your new crowns. With lab-created temporaries, you can see what your permanent crown (shape and color) will look like and whether it blends well with your smile. It also helps you determine if it is compatible with the health of your gum tissues. Also, whether or not you can eat and talk normally.
With a temporary crown, all the cosmetic and functional details are worked out in advance. There is typically an additional charge for this extra step. Once you approve, your final crown is custom-made to match the blueprint provided by the temporary, except that the final materials are stronger, of better quality, and will look far more natural.
–Always ask to see the crown before it is placed permanently in the mouth! This should be part of most dentists’ routine, but not all do it. You want to make sure the shape and color are to your liking before it is placed permanently in your smile. If the color is off or does not feel right, speak up. If you genuinely are not happy with something that cannot be adjusted chairside, ask for the crown remade. Crown esthetics can be very subjective, and their beauty is very much an individual feeling. Your input, along with your dentist’s professional experience, should join together to give you a smile you desire.
Each dentist has the responsibility of maintaining the standard of care for each treatment. Even if some dentists use inferior dental products and laboratories, they ensure that the crown fits and functions properly. Not all crowns are functional, and not all dentists or their laboratories have the same skills, training, or experience. A well-trained dentist will have no problem preparing and inserting a properly esthetic and functioning dental crown. It will take a skilled dentist and lab to make a crown look natural without anyone knowing. Ultimately, dentistry is a combination of art and science. Choosing the right dentist for you will create a happier and healthier smile.