Fixed Transpalatal Arch (TPA)
The appliance is excellent at maintaining acquired expansion. It can be designed with a solid transpalatal bar or with an omega loop allowing for adjustment and producing molar rotation. This appliance can also be fabricated in a removable version.
A transpalatal arch is used to maintain the arch width between the first molars and to de-rotate rotated molars. A wire is soldered to the first molars and runs laterally across the palate preventing a lingual drift. An adjustment loop is located in the middle of the wire and is activated as needed to de-rotate the first molars.