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': 'A substantial increase in maxillary width is usually best\nobtained by placing: \nSelect and explain. \nA. Lingual arch wire, B. A sutural expansion fixed appliance, C. Posterior intermaxillary cross elastics, D. A face bow with an expanded inner bow', 'role': 'user'}, {'content': 'Answer: B \nExplanation: In rapid maxillary expansion appliance, when a rapid heavy force is applied to the teeth, there would not be enough time for tooth movement to take place; hence, the force is directly transmitted to the sutures.\xa0\nThe appliance compresses the periodontal ligament thereby bending the alveolar process, tipping the anchor teeth, and gradually opening the midpalatal suture.\xa0\nThe sutures open with minimal movement of the teeth.\nThere is substantial increase in the\xa0maxillary width\xa0with\xa0fixed appliance than\xa0removable appliance.\xa0\n\n\u200bTextbook of ORTHODONTICS Sridhar Premkumar', 'role': 'assistant'}]