Abstract: A method of forming an aligner includes dipping a positive mold of teeth in a liquid material to form a liquid layer and curing the liquid layer to form a shell. The shell may include an inner layer including material from the liquid material and an outer layer including material from another liquid material. Prior to dipping the mold in the liquid material, features may be coupled to the layer. The features may be selected from the group consisting of an archwire, a sensor, and a bracket. The mold includes model teeth and a gingival margin on a base. Dipping may be to a predefined depth. A fluid level of the material is positioned proximate the gingival margin. The fluid level may define the edge of the shell. A set of aligners including at least one aligner having an edge that defines an opening and the edge is as-formed.