<prompt> Which of the following does not function as a space maintainer?Lingual archStainless steel crownClass II restorationPalatal expander  <response>: Lingual arch is the most effective appliance for space maintenance and minor tooth movement in lower arch.Stainless steel crown and class II restorations, maintain the space and prevent supra-eruption and tipping of adjacent teeth.Palatal expander is used for palatal expansion. It can increase the space in the arch, however, it cannot be used as a space maintainer.Textbook of orthodontics, Gowrishankar 2nd edition page 521 