US Patent 11850112 Systems and methods for forming dental appliances

A method and system for determining a cut line of an aligner are provided. The method comprises: obtaining 3D model data of a plurality of teeth and a gingiva of a subject; obtaining, using the 3D model data, for each one of the plurality of teeth, a respective one of a plurality of intersection loops; translating each one of the plurality of segmentation loops at a predetermined distance from the gingiva to generate a plurality of offset segmentation loops; identifying, within each one of the plurality of offset segmentation loops, a respective buccal portion and a respective lingual portion; sequentially joining respective buccal portions and respective lingual portions associated with each one of the plurality of offset intersection loops, thereby generating a single arch form loop; and applying the single arch form loop to an unfinished aligner to indicate the cut line on the unfinished aligner for producing the aligner.