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': 'Apexification is the treatment of choice for a permanent tooth with wide open apex when: \nSelect and explain. \nA. The pulp is necrotic, B. The pulp is vital, C. The pulp and root canals are calcified, D. There is traumatic pulp exposure during cavity preparation', 'role': 'user'}, {'content': 'Answer: A \nExplanation: Apexification is the process of inducing the development of the root and the apical closure in an immature pulpless tooth with an open apex.\nThe main aim of apexification is to preserve the Hertwig’s root sheath and apical pulp tissue.\n\nRef :Textbook of endodontics, Nisha Garg and Amit Garg, 3rd edition, pg no:548', 'role': 'assistant'}]