What is a dental crown?

A dental crown is a tooth-shaped “cap” that is placed over a tooth covering the tooth to restore its shape, size, strength, and to improve its appearance. When the crowns are cemented into place it fully encases the entire visible portion of a tooth that lies at and above the gum line.

How well do dental crowns work?

A crown will work just like a healthy tooth. However, crowns can sometimes come loose over time and may need to be replaced or cemented in again. If the decay is near the centre of the tooth and bacteria invade the pulp, the pulp may die. If this happens, the crown may need to be removed and root canal treatment will be needed to eliminate the bacteria and dead pulp.

What types of crown materials are available?

Permanent crowns can be metal, porcelain-fused-to-metal, resin, or completely ceramic.

• All-ceramic or all-porcelain dental crowns provide the best natural color match than any other crown type and may be more suitable for people with metal allergies. However, they are not as strong as porcelain-fused-to-metal crowns and they wear down opposing teeth a little more than metal or resin crowns. All-ceramic crowns are a good choice for front teeth.
• Porcelain-fused-to-metal dental crowns can be color matched to your adjacent teeth unlike the metallic crowns. However, more wearing to the opposing teeth occurs with this crown type compared with metal or resin crowns. The crown’s porcelain portion can also chip or break off. Next to all-ceramic crowns, porcelain-fused-to-metal crowns look most like normal teeth. However, sometimes the metal underlying the crown’s porcelain can show through as a dark line, especially at the gum line and even more so if your gums recede. These crowns can be a good choice for front or back teeth.
• Metals used in crowns include gold alloy, other alloys (e.g. palladium) or a base-metal alloy (e.g. nickel or chromium). Compared with other crown types, less tooth structure needs to be removed with metal crowns, and tooth wear to opposing teeth is kept to a minimum. Metal crowns withstand biting and chewing forces well and probably last the longest in terms of wear down. Also, they rarely chip or break. The metallic color is the main drawback. Metal crowns are a good choice for out-of-sight molars.

Before the process of making your crown has begun, your participating dentist will inject a local anesthetic that will completely numb the teeth, gums, tongue, and skin in that area. Next, the tooth receiving the crown is filed down along the chewing surface and sides to make room for the crown. After reshaping the tooth, your dentist will use impression paste or putty to make an impression of the tooth to receive the crown. Impressions of the teeth above and below the tooth to receive the dental crown will also be made to make sure that the crown will not affect your bite. The impressions are sent to a dental laboratory where the crown will be manufactured. The dentist will make a temporary crown to cover and protect the prepared tooth while the crown is being made. Temporary crowns usually are made of acrylic and are held in place using temporary cement. Receiving the permanent dental crown. At your second visit, your dentist will remove your temporary crown and check the fit and color of the permanent crown. If everything is acceptable, a local anesthetic will be used to numb the tooth and the new crown is permanently cemented in place. Your dentist will then have you bite on a piece of carbon paper that will indicate any high spots and reshape and polish the crown to fit the tooth.

What are “onlays” and “3/4 crowns”?

These are variations on the technique of dental crowns. The difference between these crowns and the crowns discussed previously is their coverage of the underlying tooth – the “traditional” crown covers the entire tooth; onlays and 3/4 crowns cover the underlying tooth to a lesser extent.

Does a crowned tooth require any special care?

While a crowned tooth does not require any special care, remember that simply because a tooth is crowned does not mean the underlying tooth is protected from decay or gum disease. Therefore, continue to follow good oral hygiene practices, including brushing your teeth at least twice a day and flossing once a day-especially around the crown area where the gum meets the tooth.

Is there anything else to think about?

It may be less costly and less complicated to have a tooth removed than to have tooth restoration. If the decay is near the pulp and the dentist thinks there is a chance that the pulp will die, tooth removal (extraction) may be recommended and a bridge or implant installed. If the pulp dies after the crown is placed, root canal treatment will be needed to remove the dead pulp.