Dental appliances with folded material components

A plurality of dental appliances configured to implement a plurality of stages of a treatment plan, at least one of the plurality of dental appliances comprising:

• a shell having one or more tooth apertures configured to receive and reposition one or more teeth of a patient, wherein the shell comprises:
• a specialized region configured to impart one or more specialized forces to one or more particular areas of the patient's dentition, the specialized region including a reinforcement structure comprising a rigid three-dimensional structure, wherein the rigid three-dimensional structure comprises a plurality of repeating polygonal shapes defined by folds in layers comprising a sheet of one or more polymeric materials combined with other limitations including wherein the rigid three-dimensional structure has a greater thickness than the unfolded sheet so as to impart a greater rigidity to the specialized region compared to the unfolded sheet, thereby reinforcing the specialized region for imparting the one or more specialized forces to the one or more particular areas of the patient's dentition.