<prompt> The best bio-compatible dental casting alloy is:Co-CrNi-CrTitanium alloyGold  <response>: TITANIUM AND TITANIUM ALLOYSIn vitro evaluation of titanium biocompatibility, percentage attachment efficiency, and proliferation of human fetal fibroblasts and human gingival fibroblasts reveals that a surface layer of titanium oxide Ti 2 O 3 has the ability to coexist with living tissues and organisms. Based on these studies one can conclude that titanium is relatively nontoxic, noninjurious, and not physiologically reactive. Titanium has a light weight, high strength, and excellent durability when exposed to chemical agents. However, it is susceptible to attack by acidic fluoride products.Phillips 12 ed page 126 