This group of alloys has a composition that is over 60% noble metal (gold, palladium and/or platinum), of which more than 40% must be gold. These metals are easiest to cast, provide the most accurate fit on the tooth, offer some degree of malleability (so the fit of the metal can be adjusted, if needed), and offer the most predictable bond with porcelain. So in case of a reliable metal framework noble metals may be the metal of choice for premium results. Studies report that about 10% of the female population and 5% of the male have an allergic response to nickel, chrome and/or beryllium alloys which are standart base metal substructures. Consiquently, nobel metals also are alternatives for such allergic subjects.