Crown and Bridge
Crowns: the outside of each tooth is made of enamel, which is extremely hard. Although teeth are strong and difficult to break, trauma may chip or break them.
Tooth decay may also severely weaken a tooth, with high risk that the tooth may fall apart. Root canal treatment, where the pulp of the tooth containing nerves and blood vessels is removed, can also weaken a tooth, especially if it has large fillings. Teeth may also wear down over time.
In these cases, a crown is often the best way to strengthen the tooth. A crown fits over the existing natural tooth and replaces the natural crown, the part of the tooth seen above the gums.
Bridge: bridges replace one or more missing teeth. They consist of an artificial tooth anchored to the natural teeth on each side of the gap. If a tooth is lost through an accident, or is too badly decayed to support a crown, a bridge may be the treatment of choice.
Crowns and bridges are usually made or porcelain and gold alloy. Porcelain is strong and can be made to match the colour of natural teeth. It is resistant to staining and can be cleaned if it becomes stained.
Gold alloy is use for its strength, hardness and durability. It is especially useful with molars which must withstand the force of grinding and crushing. Gold alloy and porcelain are well tolerated by the teeth and gum. Allergic reactions are extremely rare.
Teeth have many functions apart from chewing and biting, so missing teeth should be replaced for the following reasons:
To improve appearance
To prevent stresses causing damage to other teeth
To prevent the teeth near the gap from shifting
To maintain the natural bite
To improve chewing ability
You will require at least two appointments for preparation and fitting of a crown o bridge. Sometimes a tooth will need a root canal treatment and perhaps a post, before a crown or bridge treatment.
Taking Impressions of Teeth
On your first visit, the dentist will take an impression of the upper and lower teeth to make a permanent record of their appearance and how they fit together when your jaws are closed. To make an accurate reproduction of your teeth, a jaw shaped tray is filled with a soft gel like material, pushed onto your teeth and in place to set for 3-5 minutes.
Preparation for a Crown
After the area is numbed with a local anaesthetic, the tooth is shaped using a drill, making it smaller by 1-2mm. after shaping, another impression is taken to record the changes.
The impressions are sent to a dental technician who makes the crown according to specifications set by the dentist.
To protect the prepared tooth, a temporary crown is attached to the reshaped tooth with temporary cement. As a temporary crown is not as strong as the final crown, you should chew on the opposite side of your mouth and avoid hard or sticky foods.
At the next appointment, the temporary crown is removed, no drilling is needed. The new crown is placed over the reshaped tooth and checked to see if the colour and fit is appropriate. If it is, the crown is cemented onto the tooth using special dental cement.
After fitting, the crow should feel comfortable in your mouth. It is important to mention to your dentist if it feels uncomfortable or strange so they can make sure the fit is correct for your bite.
Preparation for a Bridge
The steps in preparing and fitting a bridge are similar to those of a crown. The teeth on either side of the gap are shaped by drilling.
The teeth are fitted with crowns which serve as anchors for the replacement tooth that is attached to the framework of the adjacent crowns. The whole piece is then cemented firmly in place.
Hygiene and care:
Crowns and bridges require regular flossing and brushing, with extra attention around the margins where decay is more likely. Special devices including floss threaders and “superfloss” are available for cleaning under your bridge.
Possible Side Effects of Crown or Bridge Treatment
Breakage of a tooth during preparation: when the affected tooth is evaluated whether or not the natural tooth structure is strong enough to hold a crown. If there is doubt, an extra filling may be added or the structure re inforced before shaping the tooth.
Infection of the pulp or gums: infections may occur in the pulp or the gums. When enamel is removed there is a small risk that the pulp underneath may die and become infected. If this happens, root canal may be needed.
Pain or discomfort: during treatment, surrounding gum may be injured and feel tender as the aneasthesia wears off. Any pain should not last more than two days.
Altered feeling: if the size of a tooth is changed slightly, it can affect the way the mouth feels during chewing and biting. It is important that you advise your dentist or any discomfort or strange feelings at the time of fitting.
Loose crown or bridge: if the crown or bridge has any movement. A crown may be dislodged by a strong force. It will need to be re cemented.
Allergic Responses: allergic responses to porcelain or gold are rare. If a reaction is suspected, contact your dentist.