An 8-year-old child is found to have convex facil profile, forced closing of lips, sagittal gap of 7 mm. Eschler-Bittner test produces some face improvement. This abnormality can be eliminated by means of Frankel type regulator. What is the mechanism of action of this device?

Answer options

1. Inhibition of maxilla growth in the sagittal direction
2. Normalization of upper front teeth position by means of a vestibular bar
3. Normalization of labial, buccal and lingual pressure as well as of mandible position
4. Maxillary expansion by means of a screw
5. Normalization of mandible position and growth by means of intermandibular traction