Onlays can be made of a very strong ceramic which is tooth coloured, or a metal alloy which can be a silver or gold colour. All onlay materials are very solid, which provides the strength and rigidity to withstand chewing pressures.
Onlays require two visits to complete. The first visit involves shaping and then using a special digital camera to scan a mould of the tooth into the computer. The digital mould is e-mailed to a dental laboratory where the onlay is constructed. At a second visit, the constructed onlay is then cemented onto the tooth.
In severe cases where there is not much tooth structure remaining may be more suited to a crown.