Crowns - Onlays - Bridges - Veneers Crowns Crowns are tooth shaped caps placed over prepared existing tooth structures. Crowns are used to protect heavily filled teeth and root canal filled teeth, both of which are very vulnerable to fractures. Heavily filled teeth can have hidden cracks which make them tender to bite and hot cold sensitive. If a cracked tooth is left untreated, the crack line will propagate and become larger from constantly biting and chewing on the tooth. The crack will either go through the pulp chamber (the nerve centre) of the tooth or the outside of the tooth. About 10 percent of cracks involve the nerve centre of the tooth. Specialized restorative techniques are often required to salvage the tooth. Crowns are also used to support the tooth when there is no longer sufficient tooth structure to place a filling. Crowns can also be used to cosmetically to improve the appearance of your teeth. Types of Crown Porcelain fused to metal crowns: these are the most popular type of crowns used these days; they meet both the strength and the aesthetic requirements. They have a structure of metal alloy to which opaque material is added and porcelain is fused at high temperature to produce a strong crown. Full gold crowns: these are an excellent choice for patients who are not concerned about the appearance of the gold in their mouth. Gold is a very hard wearing metal, therefore gold crowns are strongly recommended and sometimes the only choice for patients with very heavy bite or bruxist. Gold is usually the best option when the space in the occlusion is limited due to over eruption of an opposing tooth. Metal Free crowns: These crowns are made of exceptionally strong porcelain and have no metal base, they are used in patients who are either allergic to metal or want the ultimate aesthetic outcome. Onlays Onlays are partial crowns (rather than full crowns), used to protect cracked teeth or teeth that have been weakened by excessive decay. Unlike full crowns that cover the entire tooth structure, onlays only fill an existing cavity in the tooth and extend over the weak sides of the tooth, thereby preventing them from flexing and the inevitable breakage that could require a full crown if the sides are left unprotected. There are two types of onlays: Gold Onlays, used mostly on molar teeth, they are very durable and long lasting. Metal free onlays done on both premolar and molar teeth. They satisfy demand for aesthetics as well as strength. Bridge A Bridge is a custom made restoration that replaces a missing tooth or teeth. It is supported by teeth on either side of the space. To replace a missing tooth with a bridge type work, the teeth on either side of the missing one must be carefully prepared and shaped as crowns to serve as abutments so they can hold the replacement tooth or teeth in place. Veneers Veneers are thin shells made of high quality porcelain which are permanently bonded to your front teeth. They are used to achieve spectacular improvement in the appearance of teeth that have become mildly to moderately discoloured. They can also be used on chipped, stained and crooked teeth, or to close gaps (called Diastema) between front teeth. This type of restoration requires the removal of a minimum amount of tooth structure. Usually only 0.75-1 mm of the front surface of the tooth need to be shaved off, therefore veneers are very conservative, they are also resistant to staining.