Compared with Other Types of Crowns
Dental Crown Choices
A dental crown is needed when a tooth is badly broken down—either a cusp has broken off, or there are large old fillings or a large portion of tooth decay. A filling is used to fill a small portion of the tooth—a crown when the tooth has extensive damage. And when you have one made, there are three basic categories: metal (usually gold); all porcelain crown ; or porcelain fused to metal. There are some other choices of materials, such as reinforced resin, but we won’t deal with that on this page. This is some information to help you decide which of these three basic choices you want.
- Bonded all-porcelain crown – This is the most beautiful type of dental crown. Since dentists are not generally trained in dental schools in the bonding techniques required to place these crowns, you should be careful to only have them done by trained cosmetic dentists. For information on locating an expert cosmetic dentist in your area, please see our cosmetic dentist referral page.
It mimics the appearance of nature to the point where it is difficult to tell that it is not a natural tooth. It takes advantage of the new bonding technology, which allows a cosmetic dentist to bond it to your tooth so that it acts like it is one piece with your tooth—it’s like an enamel replacement.
- Porcelain onlay – On back teeth, if you want the tooth restored with all porcelain, many cosmetic dentists do porcelain onlays. An onlay involves less grinding away of tooth structure. The dentist leaves the healthy tooth structure alone as much as possible. The margins are kept high on the tooth, away from the gum, so there is much less tendency for gum inflammation which can sometimes occur with dental crowns. It also is metal-free. However, under very heavy biting pressures, there is a cracking risk with some types of porcelain onlays, so this is also a consideration.
- The CEREC crown is another type of all-porcelain that is machined by a computer in the dentist’s office. Its chief advantage is that, since it doesn’t need to be sent to a dental laboratory, your tooth can be prepared and the crown can be placed in one appointment, eliminating the need for a temporary crown.
- Gold – Where appearance is not a concern to you, gold could be the best choice. Since the gold metal is very workable, gold crowns are able to have a more precise fit than any other type. Gold also eliminates the slight possibility of chipping that exists with anything that contains porcelain. For simple longevity, nothing beats gold.
There are other metals that are used for crowns, but they are greatly inferior to gold and the savings is maybe 10%, so in my opinion it makes little sense to use them. The cheapest alloys (called non-precious or base metal alloys) are difficult to work with, they don’t cast as accurately as gold, and they are not burnishable, so the fit to the tooth is inferior, making them susceptible to leaking decay through tiny openings in the margins. They can also provoke a metal allergy, making their use even riskier.
- Porcelain fused to metal – Porcelain fused to metal crowns have a nearly natural appearance, subject to two limitations: Because they have a metal substructure, they require the use of an opaquer under the porcelain, which makes it impossible to re-create the translucency of natural teeth. They can also show a dark line at the edge, next to the gum. Dentists try to hide this line under the gum, but sometimes they are unable to do this; and sometimes the line doesn’t show when the crown is first placed but shows later, as the gum recedes But porcelain fused to metal is stronger than all porcelain.
- In situations where there is a high amount of concern about appearance, a bonded all porcelain crown (metal-free) is the nicest restoration. For the front teeth, the advantage is its natural, lifelike translucency and not having to deal with the possibility of the potentially unsightly dark line at the gumline of the tooth. For back teeth, the advantage of a porcelain onlay is the conservation of healthy tooth structure and kindness to the gums.
- Where appearance is no concern to you, gold is a logical choice, because it has the best fit and the best chance of lasting the longest. It will never crack or chip.
- For teeth that are toward the back but that still show when you smile, a porcelain fused to metal crown is a good choice. Because it isn’t in such a prominent position, it usually looks very natural, and although it’s not indestructible, it’s strong enough to resist the heaviest biting stresses.
This content was written by Dr. David Hall.
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