Systems, methods, and devices for producing appliances for expansion of the arch or palate of a patient are provided. In one aspect, a palate expanding orthodontic appliance comprises a teeth engagement portion comprising a plurality of teeth engagement structures and a force generating portion coupled to the teeth engagement portion and configured to apply force to cause the patient's palate to expand. In another embodiment, an arch expanding appliance comprises a force generating portion to apply an arch expansion force and a retention portion to hold the force generating portion on the teeth. The force generating portion is stiffer than the retention portion. The orthodontic appliances can be designed according to the specifications provided herein and manufactured using direct fabrication methods.
