Methods for directly fabricating oral appliances with 4d printing

A method comprising:

• receiving a virtual model of teeth of a patient;
• generating a treatment plan based on the virtual model to move the teeth from a first arrangement toward a second arrangement, the treatment plan including one or more displacements of the teeth;
• generating a plurality of teeth engaging structures shaped to engage the teeth and shaped to implement a first portion of the one or more displacements;
• generating one or more time-dependent structures having a first shape at a first time and a second shape at a second time, the one or more time-dependent structures configured to change from the first shape toward the second shape in response to one or more stimuli, and the one or more time-dependent structures configured to implement a second portion of the one or more displacements;
• generating a dental appliance for the teeth using the plurality of teeth engaging structures and the one or more time-dependent structures;
• and
• outputting instructions to manufacture the dental appliance using a 3D additive manufacturing process.