Orthodontics · single question
Which can cause anterior open bite EXCEPT:
Show answer and explanation
Correct answer: B. Microglossia
Anterior open bite is caused by habits or anatomy that prevent the anterior teeth from contacting: prolonged pacifier/digit habits, tongue thrust (tongue pushes between teeth during swallowing), mouth breathing/airway obstruction (altered tongue posture), or macroglossia. Microglossia (small tongue) actually has the OPPOSITE tendency — a small tongue does not exert the forward pressure needed to create an open bite. Macroglossia causes open bite; microglossia does not.
- A. INCORRECT (DOES cause open bite). Airway obstruction (enlarged adenoids, chronic mouth breathing) causes the tongue to drop forward/low, altering the balance of forces on the anterior teeth, contributing to open bite.
- B. CORRECT (this is the EXCEPTION — does NOT cause open bite). Microglossia (abnormally small tongue) does not exert the forward pressure or posturing needed to create an anterior open bite. Macroglossia (large tongue) would.
- C. INCORRECT (DOES cause open bite). Prolonged pacifier or digit-sucking habits exert direct forward and downward force on the anterior teeth, creating an open bite.
- D. INCORRECT (DOES cause open bite). Tongue thrust (atypical swallowing pattern with tongue between teeth) exerts constant forward pressure, causing anterior open bite.
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