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
Burnout of casting to expand the mould is done at a temperature of 
Select and explain. 
A. 100 C, B. 538 C, C. 675-710 C, D. None of the above
B: 538 C
Answer: B: 538 C 
Explanation: The burnout operation is done to

Dry the moisture out of the mould: The mould is heated at 212 F (100 C) for 1 hour to vapourize the moisture content in the investment.
Expand the mould to compensate for solidification shrinkage of the metal: The mould is heated at 1000 F (538 C) for 1 hour to complete mould expansion
Eliminate the pattern plastics and waxes by melting and vapourization: The mould is heated at 1250 to 1300 F (675 C to and 710 C) for 1 to 2 hours to eliminate and vapourize the traces of wax.