An apparatus is disclosed to retain an orthodontic aligner tray to teeth of the patient includes the aligner tray, a retention feature securing the aligner tray to the teeth of the patient, and an adhering agent connecting the aligner tray and the retention feature. The retention feature includes a C-shaped clip securing the aligner tray to the teeth of the patient, wherein C-shaped clip includes a single contiguous retention feature aligned to a space between two adjacent teeth and spanning from a first terminal end of the C-shaped clip at a lingual gingival margin to a second terminal end of the C-shaped clip at a labial gingival margin and at least one elongated feature in one of the lingual gingival margin and the labial gingival margin extending perpendicularly from a body of the C-shaped clip along a gum line to increase gripping force upon the teeth.
