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: Radiology
[{'content': 'Which of the following technique is useful in patients with Trismus? \nSelect and explain. \nA. Occlusal, B. PA view, C. Paralleling technique, D. Bisecting angle technique', 'role': 'user'}, {'content': 'Answer: A \nExplanation: Typically, the occlusal radiograph is especially useful in the following cases:\n\nTo\xa0locate\xa0precisely\xa0roots\xa0and\xa0supernumerary,\xa0unerupted,\xa0and impacted teeth (this technique is especially useful for impacted\xa0canines and third molars).\nTo localize foreign bodies in the jaws and stones in the ducts of sublingual and submandibular glands.\nTo\xa0demonstrate\xa0and\xa0evaluate\xa0the\xa0integrity\xa0of\xa0the\xa0anterior, medial, and lateral outlines of the maxillary sinus.\nTo\xa0aid\xa0in\xa0the examination of\xa0patients with trismus, who can open their mouths only a few millimeters; this condition precludes\xa0intraoral\xa0radiography,\xa0which\xa0may\xa0be\xa0impossible\xa0or\xa0at least extremely painful for the patient.\nTo obtain information about the location, nature, extent, and\xa0 displacement of fractures of the mandible and maxilla.\nTo determine the medial and lateral extent of disease (e.g., cysts, osteomyelitis, malignancies) and to detect disease in the palate or floor of the mouth.\n\nRef: ORAL RADIOLOGY Principles\xa0and\xa0Interpretation,Stuart C. White,Michael J. Pharoah Edition 7 page no 126', 'role': 'assistant'}]