Fig. 11. Blocking out the undercuts and trimming the line of the aligners. These designs applied gentle instantaneous force when inserting and removing the aligners to protect the periodontal tissues. The following gaps are considered to be eliminated in this case: (i) triangle-shaped gaps between teeth; (ii) the gaps between the anterior teeth are greater than 1 mm, and (iii) the gaps between the posterior teeth are greater than 2 mm. Blue means undercut areas between the teeth that need to be eliminated. Orange means undercut areas around the virtual pontic for the right maxillary canine in each aligner need to be blocked out. The dashed line is the boundary of the aligners.
