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': 'A 12 year old male patient complains of pain in  upper front teeth region and gives a history of fall while playing 30 minutes ago. Intra oral examination reveals intrusion of maxillary right central incisor by 2 mm. What is the most appropriate treatment for this patient? \nSelect and explain. \nA. Observe and allow the tooth to erupt without intervention., B. Repositioned surgically and stabilized for 4 to 8 weeks by means of a flexible splint with endodontic intervention., C. If no movement is evident after 2 to 4 weeks, the tooth may be repositioned either orthodontically  or  surgically with endodontic intervention., D. If no movement is evident after 2 to 4 weeks, the tooth may be repositioned either orthodontically  or  surgically without endodontic intervention.', 'role': 'user'}, {'content': 'Answer: A \nExplanation: The treatment for a permanent tooth with a closed root end, and intruded less than 3 mm, is to allow the tooth\xa0to erupt without intervention. If no movement is evident after 2 to 4 weeks, the tooth may be repositioned either\xa0orthodontically\xa0or\xa0surgically\xa0before\xa0ankylosis\xa0can\xa0take place. If the tooth is intruded 7 mm or more, the tooth\xa0is repositioned surgically and stabilized for 4 to 8 weeks by means of a flexible splint. In most instances the pulp\xa0will become necrotic with intrusive injuries in teeth with complete root formation. Root canal treatment should be\xa0initiated, with calcium hydroxide as a temporary canal- filling material, 2 to 3 weeks after stabilization.\nThe treatment for an intruded permanent tooth with incomplete\xa0root\xa0formation\xa0is\xa0to\xa0allow\xa0it\xa0to\xa0erupt\xa0spontaneously. If no movement is seen within a few weeks, orthodontic\xa0repositioning\xa0should\xa0 begin.\xa0 If\xa0 the\xa0tooth\xa0is intruded 7 mm or more, the tooth can be repositioned surgically\xa0and\xa0stabilized\xa0by\xa0means\xa0of\xa0a\xa0flexible\xa0splint. Endodontic therapy is often required, however, and the tooth\xa0 should\xa0be\xa0monitored\xa0closely\xa0while\xa0a decision\xa0on endodontic therapy is pending.', 'role': 'assistant'}]