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: Surgery
[{'content': 'Orthodontic treatment in management of cleft lip and palate is usually carried out in: \nSelect and explain. \nA. Deciduous dentition and mixed dentition, B. Mixed dentition, C. Mixed and permanent dentition, D. Permanent dentition', 'role': 'user'}, {'content': 'Answer: C \nExplanation: Many children with cleft lip and palate require orthodontic treatment. Orthodontic treatment is commonly carried out in two phases:\n\nMixed dentition (8 - 10 years) – to expand the maxillary arches as a prelude to alveolar bone graft.\nPermanent dentition (14 -18 years) – to align the dentition and provide a normal functioning occlusion. This phase of treatment may also include surgical correction of a malpositioned/ retrusive maxilla by maxillary osteotomy.', 'role': 'assistant'}]