<prompt> Which is the only nearly pure metal used for dental casting purposes?GoldPalladiumSilverPure titanium CP Ti  <response>: CP titanium, which is classified in four different grades, can technically be considered as an alloy because small percentages of other impurity elements are allowed as specified by a standard that has been established by the American Society for Testing and Materials ASTM for each grade. Although it is classified as commercially pure, grade 2 CP-Ti may contain up to 0.10 C, 0.30 Fe, 0.015 H, 0.03 N, 0.25 O, and 0.40 of other elements.Phillips 12th edition page 71 