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': 'Myofunctional appliances are highly effective in Class II malocclusion with \nSelect and explain. \nA. Prognathic maxilla and normal mandible, B. Prognathic maxilla and retrognathic mandible, C. Normal maxilla and Retrognathic mandible, D. Retrognathic maxilla and normal mandible', 'role': 'user'}, {'content': 'Answer: C \nExplanation: Moderate to severe skeletal class II malocclusions are ideally suited for functional appliance treatment. Class II division 1 malocclusion exhibiting a class II skeletal tendency due to a short or retrognathic mandible can be considered functional therapy.\nClass II Div. 2 type of malocclusion may be treated with functional appliances after correcting the axial inclinations of the maxillary anteriors.\nMild class III malocclusions which present with a reverse overjet and an average overbite can be regarded as potentially treatable with functional appliances.\nLow angle cases (i.e., horizontal growers) respond well as most functional appliances encourage the development of posterior teeth.\nHigh angle (vertical growers) class II cases are usually of 2 categories — those with increased overbite and those with some degree of open bite. The deep overbite type of high angle cases are successfully treated using functional appliances while the open bite type of case poses a special problem. Most functional appliances allow vertical development of the posterior dentoalveolar structures, which may induce unwanted backward rotation of the mandible.', 'role': 'assistant'}]