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': 'Apexogenesis of incompletely formed root is: \nSelect and explain. \nA. Induce the formation of apical 1/3 of root, B. Closure of apical formation in a developing tooth, C. Induce the formation of apical 2/3 of root, D. Deposition of cellular cementum at open apex', 'role': 'user'}, {'content': 'Answer: B \nExplanation: APEXOGENESIS\nApexogenesis\xa0is\xa0a\xa0treatment designed\xa0to\xa0preserve\xa0vital\xa0pulp tissue in the apical part of a root canal so that formation of the root apex may be completed.\nBecause of the depth at which this procedure is performed, preference has usually been given to the use of Ca(OH)2\xa0rather than MTA because, in the event of failure, this may facilitate reentry\xa0to\xa0the\xa0root\xa0canal\xa0to\xa0perform\xa0apexification\xa0or\xa0pulp regeneration. Also, if apexogenesis is successful and root-end formation is complete, the tooth could be reentered if desired for\xa0 conventional\xa0root\xa0canal\xa0treatment.\xa0It\xa0is\xa0unclear\xa0whether these concerns hold true in an era of microscopy and contemporary microinstrumentation.', 'role': 'assistant'}]