When teeth are heavily decayed they may be too weak to survive with just a filling. By placing a crown, a tooth may be given a new lease of life. Even when a single tooth is lost a denture may not be required as a bridge can be made which spans the gap with a tooth attached to those next to the space. Sometimes when a single small tooth is lost at the front of the mouth a simple bridge can be made which has ‘wings’ that are glued to the back of the adjacent teeth.
This results in fewer teeth being damaged by the drill.
- When a tooth is heavily decayed it is more likely to fracture and lose considerable tooth substance. The greater risk is that a fracture line may go below the margin of the gum which makes restoration more difficult or near impossible.
- Crowns may be made from several different materials, gold and porcelain being the most common types.
- Gold is usually used on the back teeth, as it has several advantages over porcelain teeth.
- Gold is strong in thin section and very small portion of your tooth needs to be drilled away before taking the impression and fitting the crown.
- The lab technician finds it easier to use gold as it shrinks less when cast and is easier to polish. Crowns of porcelain shrink when cast and the technician has to estimate this when making the crown.
- Porcelain is usually used for the front teeth but may be used for the back teeth in some cases. This material can be made to appear very natural though several factors affect this.
- Some porcelain crowns have metal inside them which gives strength and support to the porcelain. This acts as a barrier for light and gives the crown a dull colour. On posterior teeth this won’t be noticed but in the front of the mouth it can occasionally be a problem as the tooth looks duller than the natural teeth.