An interocctusal appliance is formed from a single polymer material compositionas one unitary piece or from multiple polymer materia! compositions as a two-piecepreform. The two-piece preform includes a base material and an impression materialthat has a softening point lower than the base material. Teeth are received intothe heat- softened impression material, so as to contour the impression material.A portion of the impression material also may contour to a portion of the user'spalate, in certain embodiments, substantially no polymeric material contactsthe front surfaces of the front teeth, leading to greater comfort and better airflow between front teeth, in still another embodiment, the appliance fits overfront teeth only and no polymeric material contacts the maxillary molars.
