This is a real-world medical entrance exam question, please give the true answer based on the question and selection. Topic name: None, Subject name: Dental
[{'content': 'The purest form of metal used in Dental casting \nSelect and explain. \nA. CpTi, B. NiTi, C. Gold, D. Co-Cr', 'role': 'user'}, {'content': 'Answer: A \nExplanation: Commercially pure titanium (CPTi), which is important for implants and restorative dentistry, consists of high-purity (99 wt% or higher) titanium, with oxygen, carbon, nitrogen, and hydrogen atoms dissolved interstitially.\nPhillip’s 12th edition page 80', 'role': 'assistant'}]