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': 'Lip bumper is used for: \nSelect and explain. \nA. Mouth breathing, B. Nail biting, C. For lip biting & hyperactive rnentalis, D. All of the above', 'role': 'user'}, {'content': 'Answer: C \nExplanation: Lip Bumper\nLip bumper is an appliance that makes use of the tonicity of the lip.\xa0The lip trap and excessive lip activity can be helped with a lip bumper\xa0 which prevents lip pressure on the lower incisor; their labial position gets normalised with tongue pressure. The lost arch length can also be gained with this method.\nKey Concept:\xa0\nThe lip trap and excessive lip activity can be helped with a\xa0lip bumper\xa0which prevents lip pressure on the lower incisor.\nReference: Orthodontics: Diagnosis and Management of Malocclusion and\nDentofacial Deformities 3rd\xa0ed Om P. Kharbanda pdf no 736', 'role': 'assistant'}]