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': 'Root end filling material of choice is: \nSelect and explain. \nA. MTA, B. Super EBA, C. GIC, D. Amalgam', 'role': 'user'}, {'content': 'Answer: A \nExplanation: Mineral trioxide aggregate (MTA) is composed of tricalcium silicate, tricalcium aluminate,\xa0tricalcium oxide and silicate oxide.\n\nBismuth oxide is added to the mixture for radiopacity.\npH - 12.5 (when set).\nSetting time is 2 hours 45 minutes.\nCompressive strength—40 MPa (immediately after setting) which increases to 70 MPa after 21 days.\nExcellent biocompatibility. In contact with periradicular tissues, it forms connective tissue and cementum, causing only very low levels of inflammation. So, best material for root end filling.', 'role': 'assistant'}]