Oral screen:: (A) Causes the child to breathe through the nose, (B) Allows for the passage of air through mouth, (C) Prevents passage of air through nares, (D) Allows the passage of air through mouth and nose
Answer is A. The oral screen like structure enveloping the teeth buccally/ labially help in treating the mouth breathing or thumb sucking habits. This allows for the child to shift from oral to nasal breathing, which in turn allows the nasal passages to develop and the palate to descend.
Reference: Textbook of orthodontics, 2nd ed Gurkeerat Singh page no 574