A method for producing an orthodontic or dental appliance (10) includes laminating a layer (20) of polyethylene terephthalate (PET) with a layer (21) of polyethylene to form a multilayer film, forming the multilayer film into the shape of an orthodontic appliance, trimming the formed film to a desired shape, and removing the layer (21) of polyethylene. In one embodiment, the appliance is a multi-layer structure formed from two adjacent layers (20, 22)of PET with a plurality of functional elements (25) such as sensors or actuators between the two layers (20, 22).
