Nitanium® Coil Springs enclosed in expansion modules provide slow continuous force
The Transforce palatal expander has a range of action of 8 mm from fully closed to fully open. This range can be increased in the molar region by adapting the angulation of the wires extending to the lingual sheaths in the molars. This appliance is extremely effective in correcting labial segment crowding in upper and lower arches as the expansion unit is positioned anteriorly to expand the inter-canine distance. This generates a continuous force of 200 grams in the canine region, and taking into account the lever arms extending to the molar region the force levels are reduced considerably, but are still effective in expanding inter-molar width, apparently without tipping the molars. It appears that the horizontal control achieved by the pin and tube activating mechanism, combined with occlusal forces help to prevent tipping of the molars due to the slower rate of expansion.