DENTISTRY – Crowns
What is it?
A crown is a tooth-shaped cover placed over a tooth that is badly damaged or decayed. A crown, which many people call a cap, is made to look like your tooth. Crowns may be placed for several reasons, but generally the tooth has been extensively damaged by decay or breakage and filling material can’t replace the missing tooth structure and make the tooth strong enough. A crown may hold together parts of a cracked tooth and can be used to hold a bridge in place. Crowns also are used for cosmetic purposes to cover misshapen or badly discolored teeth. Crowns can be porcelain fused to metal (PFM), or all ceramic. Metals include gold alloy, other alloys (palladium) or a base-metal alloy (nickel or chromium). The all-metal or PFM crowns are stronger and are better choices for back teeth. PFM and all-ceramic crowns look just like normal teeth. Usually, crowns last at least 10 years, but in many cases they last much longer, up to 40 years or so.
How it is done
If you need a crown, you may also need endodontic (root canal treatment) on the tooth, due to extensive decay or the risk of infection or injury to the tooth’s pulp. Not everyone who needs a crown will also need a root canal. Besides the crown, we may need to build up a foundation to support the crown. A foundation is needed if large areas of the natural tooth structure are decayed, damaged or missing. If you are receiving the crown after root canal treatment, we may insert a post-and-core foundation. To place a crown, we must file down the tooth to make room for it. After filing down the tooth, we will use a piece of thread or cord to push the gum down around the tooth, and then make an impression of the tooth. We will also take an impression of the teeth above or below the tooth that will receive the crown, to make sure the crown will not affect your bite. The impressions are sent to the lab, where the crown is made. During that time, you will have a temporary crown. These crowns are usually made of plastic and are made in your dentist’s office on the day of your visit. They are not meant to last. If a temporary crown is left in the mouth, the cement eventually washes out and the tooth can decay. At a second visit, your dentist will remove the temporary crown and test the permanent one. Sometimes crowns need additional polishing or glaze or some other adjustment before they are placed. Once the crown is ready, it’s cemented to your tooth.
You shouldn’t feel any discomfort or sensitivity after a crown is placed, though if your tooth still has the nerve in it, you may have some hot/cold sensitivity.