CROWNS AND BRIDGES IN DENTISTRY
What are Dental Crowns and Tooth Bridges?
Both crowns and most bridges are fixed prosthetic devices. Unlike removable devices such as dentures, which you can take out and clean daily, crowns and bridges are cemented onto existing teeth or implants, and can only be removed by a dentist.
How do Crowns Work?
A crown is used to entirely cover or “cap” a damaged tooth. Besides strengthening a damaged tooth, a crown can be used to improve its appearance, shape or alignment. A crown can also be placed on top of an implant to provide a tooth-like shape and structure for function. Porcelain or ceramic crowns can be matched to the color of your natural teeth. Other materials include gold and metal alloys, acrylic and ceramic. These alloys are generally stronger than porcelain and may be recommended for back teeth. Porcelain bonded to a metal shell is often used because it is both strong and attractive.
Your dentist may recommend a crown to:
- Replace a large filling when there isn’t enough tooth remaining
- Protect a weak tooth from fracturing
- Restore a fractured tooth.
- Attach a bridge
- Cover a dental implant
- Cover a discolored or poorly shaped tooth
- Cover a tooth that has had root canal treatment
How do Bridges Work?
A bridge may be recommended if you’re missing one or more teeth. Gaps left by missing teeth eventually cause the remaining teeth to rotate or shift into the empty spaces, resulting in a bad bite. The imbalance caused by missing teeth can also lead to gum disease and temporomandibular joint (TMJ) disorders.
Bridges are commonly used to replace one or more missing teeth. They span the space where the teeth are missing. Bridges are cemented to the natural teeth or implants surrounding the empty space. These teeth, called abutments, serve as anchors for the bridge. A replacement tooth, called a pontic, is attached to the crowns that cover the abutments. As with crowns, you have a choice of materials for bridges. Your dentist can help you decide which to use, based on the location of the missing tooth (or teeth), its function, aesthetic considerations and cost. Porcelain or ceramic bridges can be matched to the color of your natural teeth.
How are Crowns and Bridges Made?
Before either a crown or a bridge can be made, the tooth (or teeth) must be reduced in size so that the crown or bridge will fit over it properly. After reducing the tooth/teeth, your dentist will take an impression to provide an exact mold for the crown or bridge. If porcelain is to be used, your dentist will determine the correct shade for the crown or bridge to match the color of your existing teeth.
Using this impression, a dental lab then makes your crown or bridge, in the material your dentist specifies. A temporary crown or bridge will be put in place to cover the prepared tooth while the permanent crown or bridge is being made. When the permanent crown or bridge is ready, the temporary crown or bridge is removed, and the new crown or bridge is cemented over your prepared tooth or teeth.
How Long do Crowns and Bridges Last?
While crowns and bridges can last a lifetime, they do sometimes come loose or fall out. The most important step you can take to ensure the longevity of your crown or bridge is to practice good oral hygiene. A bridge can lose its support if the teeth or bone holding it in place are damaged by dental disease. Keep your gums and teeth healthy by Brushing with fluoride toothpaste twice a day and flossing daily. Also see your dentist and hygienist regularly for checkups and professional cleanings.
To prevent damage to your new crown or bridge, avoid chewing hard foods, ice or other hard objects.
|Teeth around the space are prepared.||The bridge is mounted and adjusted for fit and comfort.||The bridge is cemented into position.|
A crown is a cap that is placed over a tooth and held in place by dental adhesive or cement.
Crowns are used for several reasons:
- As a protective cover for badly decayed teeth or fractured teeth
- As a permanent restoration for teeth with large fillings
- To correct minor problems in natural teeth like spacing and irregular shape or severe discolouration
WHAT ARE CROWNS MADE FROM?
Crowns can be made from a variety of materials. They can be made from plastic, ceramic or metal alloys. A combination of metal and ceramic is also possible to maximise strength and simulate the appearance of natural teeth.
HOW ARE CROWNS MADE?
Firstly, a thorough clinical examination is conducted with radiographs, by the dentist. The suitability for crowns is assessed and any preparatory work is carried out. Your dentist will also be able to advise on material choices, treatment sequence and any other concerns you may have.
At the second appointment, the teeth to be crowned are prepared. This involves reduction of the tooth size (usually under local anaesthesia) followed by an impression or mould of the prepared tooth. This trimming of the tooth is required to create space for the crown to be fitted. The mould taken is then sent to a laboratory where skilled technicians will fabricate the crown. In the meantime, a temporary crown is made and fitted onto the trimmed tooth.
At the third appointment, the temporary crown is removed and the tooth surfaces cleaned. The completed crown is tried on the tooth for fit, harmony with the bite, and appearance. Finally, the crown is cemented onto the prepared tooth with dental cement.
HOW LONG DO CROWNS LAST AND HOW DO I CARE FOR THEM?
Crowns are made of inert materials that do not deteriorate over time. However, the underlying tooth is still prone to decay and gum disease.
Ceramic on the surface may chip or fracture. Avoid chewing excessively-hard substances like ice or bones. Daily brushing and flossing are essential for maintaining good oral health as well as keeping the crown trouble-free. The most vulnerable portion of the crown is the margin or the junction between tooth and crown.
Regular check-ups will enable your dentist to detect any problems with your crown and recommend necessary treatment.
A bridge is a means of replacing missing teeth using the neighbouring teeth as supporting structures. Bridges are usually performed by trimming teeth on either side of a missing tooth as is done with crowns. The crowns made are joined together by adding a tooth in between. The resulting structure is called a bridge. Like crowns, they are also fabricated in a laboratory utilising the same materials and then fitted in the mouth. Maintenance care for bridges is similar to that for crowns. The focus is on regular flossing, brushing, as well as regular check-ups.
CAN ALL MISSING TEETH BE REPLACED WITH BRIDGES?
Bridges can be used to replace a small number of missing teeth if the neighbouring teeth are sufficiently strong. The number of missing teeth, condition of the neighbouring teeth, condition of the supporting gums and bone are all important factors which need to be assessed by your dentist prior to making a bridge. Your dentist will also be able to advise on alternative methods of replacing missing teeth after a clinical examination.