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
The following appliance is used in: 
Select and explain. 
A. Space regaining, B. Maxillary arch expansion, C. Distalization of molar, D. None of the above
B: Maxillary arch expansion
Answer: B: Maxillary arch expansion 
Explanation: This is a HYRAX appliance used for maxillary arch expansion.
Several methods have been developed for RME, such as bonded Hyrax developed by McNamara and Brudon (a Hyrax with an acrylic splint bounded to the occlusal surface of posterior teeth) to minimize the vertical effects of conventional expansion appliances.