Shape engineered aligner - auto shaping

A method for fabricating an orthodontic positioning appliance having teeth receiving cavities, the method comprising:

• receiving a representation of a patient's teeth in a selected arrangement;
• fabricating the appliance based on the received representation, the appliance including a shell of polymeric sheet material comprising one or more teeth receiving cavities having a first cavity portion shaped to compensate for non-elastic deformation due to use of the appliance, the first cavity portion, when the appliance is removed from the patient's teeth, comprising (i) an upper portion and (ii) a lower portion having a proximal end beginning at the upper portion and a distal end terminating above the patient's gingival margin, the lower portion of the shell of polymeric sheet material being fabricated to include a cavity width substantially smaller than a corresponding width of a first tooth, and wherein the upper portion is shaped to match the contour of an occlusal surface of a received tooth.

A computer-implemented method for defining an orthodontic positioning appliance having teeth receiving cavities, the method comprising:

• receiving a digital representation of a patient's teeth in a selected arrangement;
• modeling an appliance based on the received representation, the appliance including a shell of polymeric sheet material comprising teeth receiving cavities wherein at least one of the cavities includes an upper cavity portion and a lower cavity portion shaped to compensate for non-elastic deformation due to use of the appliance, the at least one of the cavities shaped to contact an occlusal surface of a crown of a received tooth of the patient, and wherein the lower cavity portion of the shell of polymeric sheet material is modeled to include a cavity width substantially smaller than a corresponding width of the received tooth and the lower portion further comprises a proximal end beginning at the upper portion and a distal end terminating above the patient's gingival margin.

The method of claim 20, wherein the modeling of the shell of polymeric sheet material includes defining exterior surfaces of the appliance based on a scaled representation of the patient's teeth.

An orthodontic positioning appliance comprising:

• a patient removable orthodontic tooth positioning appliance including a shell of polymeric sheet material having teeth receiving cavities shaped to receive and apply a resilient positioning force to the patient's teeth where at least one of the cavities has a geometry shaped to at least partially match a geometry of a first patient tooth when the appliance is worn by the patient and the at least one tooth receiving cavity further includes (i) an upper portion and (ii) a lower portion shaped to compensate for non-elastic deformation due to use of the appliance;
• wherein the lower portion comprises a proximal end beginning at the upper portion and a distal end terminating above the patient's gingival margin and, when the appliance is removed from the patient's teeth, the lower portion of the shell of polymeric sheet material is produced to include a cavity width substantially smaller than a corresponding width of the first tooth, and the upper portion is shaped to contact an occlusal surface of the first tooth crown when the appliance is worn by the patient.