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': 'The occipital pull chin cup is frequently used to treat: \nSelect and explain. \nA. Maxillary prognathism, B. Mild to moderate mandibular prognathism, C. Class I skeletal cases, D. Class II skeletal cases', 'role': 'user'}, {'content': 'Answer: B \nExplanation: Types of Chin Cup\n\nOccipital pull chin cup derives anchorage from the occiput region. This is used in Class III cases with mild to moderate mandibular prognathism, who can bring their incisors in an edge-to-edge position at centric relation. Patients with short anterior facial height also benefit from this type of chin cup. This is the more commonly used chin cup.\nVertical pull chin cup derives anchorage from the parietal region. It is indicated in high angle cases or long face patients, as it helps to close the angle of the mandible and increase the posterior facial height.\n\nRef: Textbook of Orthodontics Gurkeerat Singh Second edition', 'role': 'assistant'}]