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': 'Pulp necrosis is most likely to occur after which of the following injury: \nSelect and explain. \nA. Midroot fracture., B. Intrusive luxation., C. Concussion., D. Complete crown fracture.', 'role': 'user'}, {'content': 'Answer: B \nExplanation: These injuries cause severe damage to the neurovascular bundle and to the periodontium. The blood supply and neurovascular tissues are crushed completely and, in teeth\xa0with partially to completely closed apices, the pulpal prognosis is extremely poor, with almost a 100% probability of pulpal necrosis. Because of the severe damage to the periodontium, the probability of ER is extremely high in these injuries.', 'role': 'assistant'}]