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': 'The anchorage utilized by quad helix is: \nSelect and explain. \nA. Simple, B. Reinforced, C. Extraoral, D. Reciprocal', 'role': 'user'}, {'content': 'Answer: D \nExplanation: Anchorage in which the resistance of one or more dental units is utilized to move one or more opposing dental units is reciprocal anchorage.\xa0\nReciprocal anchorage is also employed in the correction of Class II malocclusion where intermaxillary elastics are used from the maxillary to the mandibular arch, the\xa0\nAnother simple form of reciprocal anchorage is the correction of posterior crossbite by the use of palatal expansion screw or Quad helix.\xa0\n\n\u200bTextbook of ORTHODONTICS Sridhar Premkumar', 'role': 'assistant'}]