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': 'zone which is absent when repair is done with MTA as compared to calcium hydroxide: \nSelect and explain. \nA. Zone of calcification, B. Zone of necrosis, C. Zone of vascular inclusion, D. None of the zone is absent', 'role': 'user'}, {'content': 'Answer: B \nExplanation: Zones formed with calcium hydroxide (CH) pulp therapy from below CH to normal pulp are:\n\nZone of liquefactive necrosis\nZone of coagulative necrosis\nInflammatory response\nHard tissue barrier with vascular inclusions.\n\nThe necrosis with pure CH is due to its high PH. But dycal which is a hard setting CH formulation forms hard tissue barrier without causing necrosis.\nZones formed with MTA pulp therapy\n\nVery narrow or even absent coagulative necrosis\nReparative dentinogenesis zone resulting in dentin bridge with fewer vascular inclusion (high quality).\n\nMTA is a biocompatible material. The excellent bacteria-tight seal accounts for the success with MTA.', 'role': 'assistant'}]