Crowns are utilized in several instances, but generally the tooth has been extensively damaged by decay fracture, cracking, or breakage and there is insufficient tooth structure remaining to support a filling. A crown may hold together parts of a cracked tooth and can also be used to replace a missing tooth and support a bridge . Crowns can also be used for enhancing your appearance or for cosmetic purposes to close spaces and cover misshapen or discolored teeth. Crowns are also very useful in rebuilding the chewing mechanism (your occlusion). Crowns are strong themselves and can withstand the forces generated by your jaws.
Restorative crowns are custom made to fit your exact tooth in a dental laboratory. Crowns can be all gold, all ceramic or porcelain fused to metal (PFM). PFM metals include gold alloy, other alloys (palladium) or a base-metal alloy (nickel or chromium). The all gold or PFM crowns are stronger than the all ceramic due to the fact that the have a metal framework and are good choices for back teeth. All ceramics can be used on back teeth where the chewing mechanism (occlusion) is stable. PFM and all-ceramic crowns look just like your normal teeth and many times can be made to look far better than what you have. Gold crowns are gold in color and are very effective where the chewing forces are heavy as they resist breakage.
Temporary crowns used as interim restorations until a restorative crown has been custom made. Temporary crowns can be made of acrylic or stainless steel.
All ceramic crowns will last at least 5 years while gold crowns will last 7 years or longer. In cases where the chewing mechanism is stable, the patient receives consistent cleaning and check-ups as well and has good home care, crowns can last significantly longer. Well placed crowns made of high quality materials have been know to last decades. The good news for you is that crowns can help you save your own teeth and help you enjoy the benefits of long term dental health unlike our parents and grandparents who may time lost teeth to dental diseases.
Preparing The Tooth for Reconstruction with a Crown
If your tooth needs a crown, there may be enough damage that could cause the need for endodontic or root-canal therapy on the tooth, due to extensive decay or the risk of infection or injury to the tooth's inside tissue, the pulp. Not everyone who requires a crown will also need root canal therapy, your dentist will assess your particular needs.
To support the crown, your dentist may need to build up a foundation to strengthen remaining tooth. A foundation would be used if large areas of the natural tooth structure were decayed, damaged, undermined or missing. If you are receiving the crown after root-canal treatment, your dentist may insert a post along with the foundation. To place a crown, your dentist must remove 1 to 2 millimeters of the tooth to make room for the crown to fit properly. If you are receiving an all-gold crown, less tooth structure may need to be removed because these crowns need less space than Porcelain Fused to Metal or all-porcelain crowns.
After shaping the tooth, your dentist will use a piece of thread or cord to move the gum tissue aside around the tooth, and to make room for impression material. The impression material sets in five or six minutes and is removed. This process will allow an very precise model of the tooth. Your dentist will also need to take an impression of the opposing teeth to make sure that the crown properly fits your particular bite.
The impressions are then sent to the dental laboratory, where the crown is fabricated. During the time the crown is being fabricated in the dental laboratory, you will have a temporary crown placed on the prepared tooth. These temporary crowns are usually made of an acrylic substance and are made in your dentist's office on the day of your visit. They are not meant to last, only to protect the tooth. Temporary crowns left in the mouth over a long period of time, the cement will eventually wash out and the tooth can develop decay and cause significant problems.
At a second visit, your dentist will remove the temporary crown and check the fit and the bite relation of the permanent crown. New crowns may need additional polishing or glazing before they are placed. Once the crown is ready, it's cemented to your tooth and you are ready to use the tooth as normal.
After A Crown
You shouldn't feel any significant discomfort or sensitivity after a crown is placed, although if your tooth still has the nerve in it, you may have some hot/cold sensitivity for a while. If you notice pain or sensitivity when you bite down, you should contact your dentist. This may mean that your bite is not balanced. This can be easily fixed.
You may notice a dark line next to the gumline on your newly crowned tooth, if you have a PFM crown. This dark line is the metal of the crown showing and is a normal situation. A crown does not protect the tooth from decay or gum disease. You must continue practicing good oral hygiene to prevent further tooth destruction.
If you have a crown that breaks, chips, comes loose or falls off, call your
dentist's office immediately. You can replace the crown temporarily using denture
adhesive or temporary cement sold for this purpose until you can get in to
see your dentist.