It delivers a uniform, slow, continuous force for maxillary expansion, molar rotation, distalization and arch development.
For all simulations, 1000 g of protraction forces were applied, as studies have shown that 500 1500 g is an appropriate force load for maxillary protraction [19].
However, no firm evidence exists in the literature regarding the optimal force levels for maxillary dentoalveolar intrusion.
Some clinicians think that elastic force of 400 g on each side is insufficient and need even more force for adequate maxillary protraction, but there is lack of substantial studies about proper protraction force.
The protraction forces of maxillary protraction appliances are applied to the first maxillary molar, so the effects are more dentoalveolar than skeletal in nature.
Table 1 shows different locations and directions of force application, which simulate eight clinical protocols for maxillary protraction.
But what is the equivalent force for retracting a maxillary central incisor in the class II, division 2 patient?
Rapid maxillary expansion (RME), indicated in the treatment of maxillary deficiency directs high forces to maxillary basal bone and to other adjacent skeletal bones.
Hence, biomechanically, maxillary protraction combined with maxillary expansion appears to be a superior treatment modality for maxillary retrognathia than maxillary protraction alone.
After maxillary protraction, we applied a fan type active plate for maxillary expansion for 11 months for occlusal interdigitation.
