A method for producing an orthodontic or dental appliance includes laminating a layer of polyethylene terephthalate (PET) with a layer 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 of polyethylene. In one embodiment, the appliance is a multi-layer structure formed from two adjacent layers of PET with a plurality of functional elements such as sensors or actuators between the two layers.
