US Patent 11648087 Mold and aligner with features showing cut line

Embodiments relate to adding customized cut line information to a shell that is to be formed over mold of a dental arch. In one embodiment, a processing device generates or receives a digital three-dimensional model of a mold for a dental arch of a patient. The processing device determines a cut line for a shell that is to be formed over the mold for the dental arch of the patient. The processing device then supplements the digital three-dimensional model by adding an auxiliary structure to the digital three-dimensional model, wherein the auxiliary structure comprises at least one of an elevation or a depression that extends along the cut line in the digital three-dimensional model, wherein the auxiliary structure will cause the shell formed over the mold to have an impression of the auxiliary structure that identifies the cut line.