What is the magnitude of the extraoral force applied on the superior arch as described in the source?

• A. 100 g
• B. 200 g
• C. 400-500 g
• D. 1000 g

Answer: (D)

In this context, extraoral forces used to influence the maxilla with headgear are applied in an orthopedic range, not just for dental tooth movement. The force must be large enough to affect skeletal growth centers while still being tolerable for the patient. The source describes the force magnitude on the superior arch as about 1000 g, or roughly 9.8 N. This level is considered sufficient to produce skeletal changes at the sutures of the maxilla when the appliance is worn for the recommended duration, whereas lower forces tend to yield mainly dental tipping rather than skeletal effects. So 1000 g is the stated magnitude because it achieves the intended orthopedic impact on the maxillary complex while balancing tissue tolerance and clinical practicality.