Crowns

A dental crown resembles a cap in the shape of a tooth. It is placed on top of a tooth, covering it to reconstruct its shape, size, strength, and to improve its appearance.

Once cemented, crowns cover completely the portion of the tooth that is above the gum line.

Reasons why crowns are necessary:

• To protect a weakened tooth from breaking, or to keep intact a cracked tooth. Teeth usually become weak following a big cavity, a big filling or a fracture.
• To restore an already broken tooth or a severely worn tooth.
• To cover or support a tooth that has a big restoration (filling) when not much healthy tooth structure is left.
• To cover a malformed or severely discoloured tooth.
• To cover a dental implant.

Types of crowns

• Gold crowns. These are the crowns that last the longest. They resist very well to the chewing forces, fracture rarely, and cause very little wear to the opposing teeth. The gold color is the main disadvantage. Therefore, a gold crown would be a good choice for a molar in the back.
• Porcelain fused to metal. These crowns are more aesthetic than the gold ones. They can resemble a lot a natural tooth. The metallic portion helps strengthen the tooth, but the porcelain can get fractured. Sometimes the gold underneath the porcelain can become apparent, especially at the gum line.
• Porcelain. These are the most aesthetic crowns. The appearance and the colour can match the natural teeth. They are less solid than the gold crowns or the porcelain fused to metal crowns, though there are some new varieties of resistant porcelain that are offered. They are therefore recommended for anterior teeth favouring the aesthetics and a nicer smile.
• Temporaries. These crowns are made by the dentist from acrylic or stainless steel materials, and serve as temporary restorations while waiting for the permanent crown to be shaped in a dental laboratory. These crowns are not very solid and should be worn for only a few weeks.

Steps in the preparation of a crown

• First visit. Having already examined the x-ray of the tooth, the dentist can determine if it needs a root canal before putting a crown on it. A root canal allows the placement of a post that makes the crown more solid in cases where the tooth is very destroyed by the cavity. If a root canal is not necessary, the tooth can necessitate a reconstruction with a filling to create a better support. The tooth is then reduced all around creating space for the crown. An impression of the tooth is taken and sent to the dental laboratory where the crown is created. A temporary is then placed and remains there until the next appointment.
• Second visit. The cementation of the permanent crown is done two to three weeks later. The dentist removes the temporary, verifies the adaptation and the color of the crown before installing it with dental cement.

Care of the temporary crown

• Avoiding sticky foods like caramel or chewing gum, which could remove the temporary crown from the tooth.
• Avoiding hard foods that could fracture the temporary crown.
• Avoiding chewing on the side of the mouth where the temporary crown is.

Life span of a crown

A crown can last between five and twenty years, depending mainly of the oral hygiene and the maintenance, the material of the crown (gold versus porcelain), and also of oral habits (grinding the teeth, chewing on ice or biting nails lessen the life span of a crown).

Maintenance of a crown

One should not forget that even though the crown cannot get decay, the tooth underneath it can be exposed to cavity and gum disease. Therefore, good oral hygiene should be maintained, including brushing and flossing.

Cost of a crown

The price of a crown varies depending on which part of the country we live in. In general, the cost varies between 900$ and 1,500$, not including the cost of a root canal should it be necessary.

References