A Crown (or Cap) is used to repair a damaged or heavily filled tooth & it can also alter the shape or colour of the tooth, as well as strengthening it.
The tooth is shaped to allow enough space for the crown to fit over it & then an impression is taken. A Dental Technician then makes the crown out of the most suitable material:
All Porcelain for front teeth, where the appearance of the crown is most important.
Porcelain bonded to a gold alloy for back teeth, where the strength of the crown is the most important factor.
All Gold for back teeth in exceptional circumstances, when the patients bite is very strong or there’s very little space.