Patent ID: 8905756

Claim:
A thermoformed dental appliance comprising at least two plies of thermoformable material, wherein a first ply comprising a copolyester material, having a first set of characteristic properties, provides a first primary surface of the dental appliance and wherein a second ply comprising a copolyester ether material different from the first ply, having a second set of characteristic properties, provides an opposing second primary surface of the dental appliance, wherein the first ply and the second ply have a combined thickness before thermoforming of from 0.25 to 5 mm; wherein the first ply comprises a copolymer of deformable thermoplastic or elastomeric material having properties suitable for use in a dental appliance, the deformable thermoplastic or elastomeric material comprising one of: ethyl vinyl acetate, polypropylene, polyvinylchloride, low density polyethylene, or high density polyethylene, and; wherein the copolyester ether material comprises cyclohexane dicarboxylic acid, ethylene glycol and cyclohexane-1,4-dimethanol; and the dental appliance having teeth receiving cavities conforming to a shape of a patient's mouth or a modification of the patient's mouth based on a stone model, wherein the first primary surface comprises an inner surface arranged to be in contact with a patient's teeth, that forms the inner surface of the dental appliance, and wherein the second primary surface forms an outer surface towards the patient's mouth tissue, and the first ply and the second ply are joined at a common interface.