Known by some as “caps”, a dental crown is a covering that protects and covers the entire tooth. These are frequently used on teeth that need to be re-enforced in order to prevent fracture or breaking. Here are some common reasons that crowns are recommended to restore teeth:
- Large fillings, where the tooth may fracture in the future
- Previous root canal therapy on a tooth (which can render a tooth more brittle and prone to breaking)
Crowns are most frequently made with a tooth-colored porcelain outer shell, in order to give the smile a natural and bright appearance.
The first step in preparing a tooth for a dental crown involves reducing and contouring the tooth in order it may properly receive the crown that will be fit over it. An impression of the tooth is made, along with the surrounding teeth and gum tissue, and then it is sent to a lab in order to be made. The materials used to make a dental crown, as well as the porcelain that is laid over it in order to give the crown a natural appearance, are refined under very high levels of heat, which is why they are commonly made in a separate laboratory setting. In the interim, a patient will receive a temporary dental crown, which is made from acrylic of a shade matching the existing teeth. When the new dental crown is ready, it is placed on the tooth, and the dentist will verify that all the edges, or margins, of the crown fit perfectly to the existing tooth structure. Once that is verified, the crown is then cemented in place.
When a person is missing a tooth in the middle of their smile, the teeth around them can be connected by a series of crowns (or a “bridge”) to fill the space created by the loss of a tooth (or in some cases, multiple teeth) and also regain the chewing function that the tooth once provided. Similar to dental crowns, bridges are also frequently made with a tooth-colored porcelain outer shell, as it can be made to closely match the appearance of natural teeth.
Bridges also require at least two appointments. In the first appointment, the dentist will select the appropriate shade for the new crown or bridge, make all the necessary preparations to the teeth, take dental impressions which are used to design the crown/bridge, and finally, create a provisional (or temporary) bridge, which will protect the teeth being worked on, as well as to allow getting accustomed to the permanent restoration. At the next appointment, the temporary restoration will be removed and replaced by a permanent crown or bridge. The dentist will verify that all the edges, or margins, of the bridge fit perfectly to the existing tooth structure. Once that is verified, the bridge is then cemented in place.