Methods for direct fabrication of dental appliances with varying feature thicknesses and associated systems

A system comprising:

• one or more processors;
• memory including computer program instructions that, when executed by the one or more processors, cause the system to perform a computer-implemented method comprising:
• receiving an intraoral scan of a patient's teeth, wherein the intraoral scan captures an initial arrangement of the patient's teeth;
• generating a three-dimensional (3D) dental model of the patient's teeth using the intraoral scan;
• identifying a target arrangement for the patient's teeth using a treatment plan applied to the 3D dental model;
• identifying a movement path to move the patient's teeth from the initial arrangement toward the target arrangement through a plurality of intermediate arrangements in accordance with the treatment plan;
• identifying appliance geometries for a plurality of aligners to implement the movement path, wherein at least one aligner of the plurality of aligners comprises an appliance shell having a plurality of cavities that receive a patient's teeth and apply forces to reposition the patient's teeth along the movement path,
• wherein identifying the appliance geometries comprises identifying one or more protrusions of the at least one aligner to control application of the forces to the patient's teeth, and wherein the one or more protrusions are integrally formed in the appliance shell and extend inward from an interior surface of the appliance shell toward at least one tooth received by the appliance shell to define a contact point for application of force to the at least one tooth;
• exporting into an additive manufacturing file a representation of the at least one aligner;
• and
• instructing an additive manufacturing machine to directly fabricate the at least one aligner in a layer-by-layer fashion.