Cosmetic Dentistry

A dental crown is also known as a "cap". It is placed over a tooth, and covers the tooth to restore its shape, size, strength, and/or to improve its appearance. When cemented into place, the crown will fully encase the entire visible portion of a tooth that lies at and above the gum line.

A dental crown may be needed for a number of reasons:

• To protect a weak tooth from breaking or to hold together parts of a cracked tooth

• To cover and support a tooth with a large filling when there isn't a lot of tooth left

• To restore an already broken tooth or a tooth that has been severely worn down

• To cover misshaped or severely discoloured teeth

• To cover a dental implant

A crown is a method of restoring a tooth and is manufactured to be a replica of the tooth as it was before the damage took place.

Preparing a tooth for a crown requires two visits to the dentist. During the first visit, your dentist will examine and prepare the tooth; and at the second visit, place the permanent crown.

Before the process of making your crown, your dentist will anaesthetize (numb) your tooth and the gum tissue around the tooth, unless you are told otherwise. The tooth being crowned is filed down to make room for the crown. The amount removed depends on the type of crown used. After reshaping the tooth, your dentist will make an impression of the tooth to receive the crown. Impressions of the teeth above and below the tooth having the crown will also be made to make sure that the crown will not affect how you bite. These impressions are sent to a dental laboratory where the crown will be made. The crown is usually returned to your dentist's office in 2 to 3 weeks. The temporary crown placed is acrylic and is held in place using a temporary cement.

When you return, your dentist will remove your temporary crown and check the colour and the permanent crown fit correctly. If happy, a local anaesthetic will be used to numb the tooth and the new crown is permanently cemented in place.

Permanent crowns can be made from all metal, porcelain-fused-to-metal, all resin, or all ceramic.

Metals used in crowns include gold alloy, other alloys (for example, palladium) or a base-metal alloy (for example, nickel or chromium). With metal crowns, less tooth structure needs to be removed in comparison to the other crowns. Metal crowns are good for biting and chewing forces and probably take the longest to wear down. Metal crowns rarely chip or break. The disadvantage is the metallic colour so metal crowns are a good choice for out-of-sight molars.

Porcelain-fused-to-metal crowns can be colour matched to your other teeth. However, they are more wearing to the opposing teeth compared with metal or resin crowns. It is also possible that this crown's porcelain portion can also chip or break off. 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.

All-resin dental crowns are less expensive than other crown types. However, they do wear down over time and are more prone to fractures.

All-ceramic or all-porcelain dental crowns provide the best natural colour match and may be more suitable for people with metal allergies. However, they are not as strong as some other crowns, and they wear down opposing teeth a little more. All-ceramic crowns are a good choice for front teeth.

Temporary versus permanent crowns. Temporary crowns are made by your dentist, whereas permanent crowns are made in a dental laboratory. Temporary crowns are made of acrylic or stainless steel and can be used as a temporary restoration until a permanent crown is constructed by the dental laboratory.

Discomfort or sensitivity. Your newly crowned tooth may be sensitive immediately after the procedure, when the anaesthesia begins, to wear off and you may experience some heat and cold sensitivity. Your dentist may recommend that you brush your teeth with toothpaste designed for sensitive teeth. If you find you are getting pain or sensitivity that occurs when you bite down, there is no need to worry, call the front desk team and make an appointment to see your dentist as it usually means that the crown is too high on the tooth.

Chipped crown. Crowns can sometimes chip. If the chip is small, a resin can be used to repair this with the crown staying in your mouth. If more than a chip, the crown may need to be replaced.

Loose crown. Sometimes the cement washes out from under the crown. This allows the crown to become loose and bacteria to get in and cause decay to the tooth that remains. If your crown feels loose, call and speak to the practice's front desk team who will be able to make you an appointment.

Crown falls off. Sometimes a crown may fall off. If this happens, clean the crown and the front of your tooth. You can replace the crown temporarily using dental adhesive or temporary tooth cement that is sold in stores for this purpose. Contact the practice's front desk team immediately and they can make you an appointment with your dentist to either re-cement your crown in place; if not, a new crown will need to be made.

Allergic reaction. Because the metals used to make crowns are usually a mixture of metals, an allergic reaction to the metals or porcelain used in crowns may occur, but this is extremely rare.

Dark line on crowned tooth next to the gum line. A dark line next to the gum line of your crowned tooth is normal, particularly if you have a porcelain-fused-to-metal crown. This dark line is simply the metal of the crown showing through.

On average, dental crowns last between 5 and 15 years. The life span of a crown can depend on the amount of wear and tear the crown is exposed to, how good oral hygiene is, and your personal dental habits. You should try to avoid grinding/clenching your teeth, chewing ice, biting your fingernails, and using your teeth to open packaging.