A dental restoration or dental filling is a biocompatible material used to restore the function, integrity and morphology of missing tooth structure, usually as a result of decay or trauma. Teeth are restorable, provided there is sufficient remaining tooth structure necessary for the retention of a restoration. Most often a tooth coloured restoration or filling can be used to restore tooth structure. However, in certain situations it may be necessary to gain additional retention by placement of pins or in cases where excessive tooth structure has been lost an indirect restoration such as an inlay, onlay, overlay or crown may be required.