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
Calcium silicate based material is: 
Select and explain. 
A. MTA, B. Geristore, C. Dieket, D. Retroplast
A: MTA
Answer: A: MTA 
Explanation: Mineral trioxide aggregate was developed by Dr Torabinejad in 1993. 
It contains tricalcium silicate, dicalcium silicate, tricalcium aluminate, bismuth oxide, calcium sulfate and tetracalcium aluminoferrite.
pH of MTA is 12.5.

Textbook of Endodontics Nisha Garg 3rd Ed