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': 'Which of the following does not function as a space maintainer? \nSelect and explain. \nA. Lingual arch, B. Stainless steel crown, C. Class II restoration, D. Palatal expander', 'role': 'user'}, {'content': 'Answer: D \nExplanation: Lingual arch is the most effective appliance for space maintenance and minor tooth movement in lower arch.\nStainless steel crown and class II restorations,\xa0maintain the space and prevent supra-eruption and tipping of adjacent teeth.\nPalatal expander is used for palatal expansion. It can increase the space in the arch, however, it cannot be used as a space maintainer.\nTextbook of orthodontics, Gowrishankar 2nd edition page 521', 'role': 'assistant'}]