Systems, methods, and devices for producing appliances for expansion of the arch of a patient are provided. 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 retention portion comprises a flexible portion and a stiff portion. The force generating portion applies a force to move teeth associated with the flexible portion, while the stiff portion resists movement of its associated teeth. The orthodontic appliances can be designed according to the specifications provided herein and manufactured using direct fabrication methods.