Oral screen:
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
Causes the child to breathe through the nose
Allows for the passage of air through mouth
Prevents passage of air through nares
Allows the passage of air through mouth and nose