<prompt> Which of the following is an example of group III myofunctional appliances?ActivatorBionatorFrankelTwin block  <response>: Myofunctional appliances can be categorised as follows:Group I: Appliances that transmit muscle force directly to the teeth e.g., Vestibular screen.Group II: These appliances reposition mandible and the resultant force is transmitted to the teeth and other oral structures e.g., Activator, Bionator.Group III: They also reposition the mandible but their area of action is vestibule e.g., Frankel appliance.Key ConceptGroup III: They also reposition the mandible but their area of action is vestibule e.g., Frankel appliance.Reference: Textbook of orthodontics 2nd ed Gurkeerat Singh page no 502 