The expansion produced by the vestibular portion of Frankel appliances results from removal of which pressures?

The expansion produced by the vestibular portion of Frankel appliances results from removal of which pressures?

• A. Dental crowding
• B. Cheek and lip pressure
• C. Tongue pressure
• D. Bite pressure

Answer: (B)

The key idea is that the vestibular portion expands the arches by removing the inward forces from the soft tissues of the face. The buccal shields sit in the buccal vestibule and push the cheeks and lips away from the teeth, eliminating the compressive pressure those muscles normally exert on the dental arches. With those cheek and lip pressures relieved, the teeth can spread apart and the maxilla can widen more readily, aided by the tongue pressing against the palate. Bite (occlusal) pressure isn’t the main driver here, and dental crowding isn’t the mechanism of expansion—it's the removal of cheek and lip pressure that allows the expansion to occur.

The key idea is that the vestibular portion expands the arches by removing the inward forces from the soft tissues of the face. The buccal shields sit in the buccal vestibule and push the cheeks and lips away from the teeth, eliminating the compressive pressure those muscles normally exert on the dental arches. With those cheek and lip pressures relieved, the teeth can spread apart and the maxilla can widen more readily, aided by the tongue pressing against the palate. Bite (occlusal) pressure isn’t the main driver here, and dental crowding isn’t the mechanism of expansion—it's the removal of cheek and lip pressure that allows the expansion to occur.