What's the purpose and function of a Cap or Crown?

When we have fractures in our bones we place a cast on the limb that is broken. In doing so, the immobilization allows for the bones to form a callus and mend. Our bodies have great healing capabilities, EXCEPT for a few tissues. Nuerological, optical, and tooth tissue all have very limited healing capabilities. The enamel that covers the outer surface of our teeth does not have regenerative capabilities. Therefore, once the enamel is fractured it will not heal. To prevent the fracture from propagating either deeper into the tooth, hence, damaging the nerve or causing the loss of the tooth, we often choose to cast the tooth with a crown. Like the cast on a broken arm, the crown restoration will immobilize the fractured segments. Immobilization of these fractured segments is meant to prevent the fracture from propagating deeper into the tooth as the tooth is used for chewing and is cycled between very cold foods (ice cream) and very warm foods (hot coffee). However, since the enamel will not heal, the cast needs to be a left on the tooth forever.

How is a crown or cap placed on a tooth?

Crowning a tooth is usually a very simple and straight-forward process that well trained dentists and certified laboratory technicians perform routinely. After a thorough examination and consultation with your dentist, some preliminary molds may be taken of your existing teeth. This will give your dentist some information to help him/her make some important decisions on the placement of the crown. Next, the material that the crown is to be made from will be chosen. This decision will be based on several very important factors:

• What are your desires and expectations as a patient?
• Where is the tooth that needs the crown located in the mouth? (i.e., Is it a front tooth, back tooth, or somewhere in between?)
• Have you had other crowns placed and what type of crowns are they?
• Do you clench or grind your teeth?
• What is the pathology that the placement of the crown is addressing?
• Do you have any metal allergies?
• What is the existing health of the surrounding teeth and gum tissues?

1) Gold
2) Porcelain Fused to Gold
3) Full Porcelain (Procera ™)

Prior to beginning the preparation of the tooth, your dentist will administer local anesthetic to ensure complete comfort during the tooth shaping. Your medical history, past experiences with local anesthetics, and anxiety levels will help your dentist choose the best anesthetic to use. Many dentists will offer Nitrous Oxide gas, better known as "laughing gas", to help those individuals that are more anxious. Once your comfort is assured, the tooth will be shaped to some very exact specifications. This process is done under very controlled conditions to protect your tooth and gum tissue from injury. Once the tooth is shaped, another mold will be made of the tooth and a color will be chosen for cases where white porcelain will be used. On occasion, the dentist will utilize the laboratory technician's expertise to match a difficult tooth color. This is called a custom shade. The mold will be delivered to the certified laboratory for fabrication of the appropriate type of crown. As for your prepared tooth, a custom temporary crown will be placed.

The temporary crown will serve several important functions.

1. Protect the tooth during chewing
2. Stabilize the tooth to keep it from shifting
3. It will look very nice
4. It will keep you comfortable during eating and drinking.

The temporary crown will be glued in place with temporary cement. It will remain in place until the second appointment, approximately 2 weeks following the first visit. During the second appointment, the dentist will gently remove the temporary crown, thoroughly clean the tooth, adjust and cement the new permanent crown with very strong luting cement. Individuals usually do perfectly fine without the use of anesthetic during this last step.