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': 'Anterior vibrating lines can be recorded during impression making by: \nSelect and explain. \nA. Valsalva maneuver, B. Speaking “ah” in short normal bursts, C. Speaking “ah” in short vigorous bursts, D. Both 1 and 3', 'role': 'user'}, {'content': 'Answer: D \nExplanation: Anterior vibrating line is an imaginary line at the junction of the attached tissue overlying the hard palate and the immediate movable tissue of the soft palate. It is always on soft palate. Due to the projection of the posterior nasal spine, the anterior vibrating line is not a straight line, but takes the shape of a cupid’s bow. It is located by:\n\nValsalva maneuvre—patient is asked to hold both nostrils and gently blow through the nose. This will place the soft palate inferiorly at the junction of the hard palate and the junction can then be marked.\nIt can also be located by instructing the patient to say ‘ah’ in short vigorous bursts.\n\nPosterior vibrating line is an imaginary line at the junction of the aponeurosis of the tensor veli palatini muscle and the musculature of the soft palate. It is the demarcation between the part of the soft palate that has limited movement during function and the remainder of the soft palate that is markedly displaced during function. It is a slightly curved line.\n\nIt can be located by instructing the patient to say ‘ah’ in short bursts but in a normal, unexaggerated manner.\n\nKey Concept:\nAnterior vibrating lines can be recorded during impression making by Valsalva maneuver or by\xa0 Speaking “ah” in short vigorous bursts. Posterior vibrating line can be recorded by speaking “ah” in short normal and unexaggerated bursts.\nRef: Textbook of prosthodontics V Rangarajan Ed. 2nd', 'role': 'assistant'}]