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': 'First to classify malocclusion on structural basis? \nSelect and explain. \nA. Salzmann, B. Kingsley, C. Angle, D. Katz', 'role': 'user'}, {'content': 'Answer: A \nExplanation: Salzmann in 1950 was the first to classify on occlusion based on the underlying skeletal structures.\n1. SKELETAL CLASS I\n2. SKELETAL CLASS II\n3. SKELETAL CLASS III\nIn 1899,\xa0Edward Angle classified malocclusion based on the mesial-distal relation of the teeth, dental arches and jaws.\nMorton Katz (1992) shifted the focus from the molars, canines and incisors to the region of premolars for the purpose of classifying malocclusion.\nKINGSLEY (1956)\nBased on the nature of the habits, Kingsley (1956) classified habits as:\n\nFunctional oral habit -\xa0E.g.\xa0mouth breathing.\nMuscular habits - Eg.\xa0tongue thrusting, cheek/lip biting.\nCombined muscular habits - Eg.\xa0thumb and finger sucking.\nPostural habits.\n\tChin-propping\n\t\nFace leaning on hand\nAbnormal pillowing.\n\n\n\nRef: Textbook of orthodontics Gurkeerat Singh 2nd ed page no 175', 'role': 'assistant'}]