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': 'The common preoperative causes of endodontic treatment failure include all of the following except which one? \nSelect and explain. \nA. Misdiagnosis, B. Leaking coronal restoration, C. Poor case selection, D. Error in treatment planning', 'role': 'user'}, {'content': 'Answer: B \nExplanation: Failure\xa0 of\xa0 previous\xa0 endodontic\xa0 therapy\xa0 can\xa0 be\xa0 attributed\xa0 to various\xa0 factors,\xa0 such\xa0 as\xa0 procedural\xa0 errors,\xa0 missed\xa0 canals,\xa0 or persistent periapical pathosis. Knowledge of the cause of failure is pertinent to the treatment of these cases because it allows the cause to be adequately rectified.\nMisdiagnosis, poor case selection and\xa0 error in treatment planning\xa0 are the preoperative causes and leaking coronal restoration is the postoperative cause of endodontic therapy failure.\nRef: Cohen pathways of Pulp 11th ed page no 44', 'role': 'assistant'}]