An antenna includes at least one antenna radiating element and a dielectric structure defining a cavity containing a fluid dielectric. The dental appliance having the necessary stiffness or strength to firmly secure the appliance on the teeth and provide controlled forces required for repositioning the teeth, until such time as removal of the appliance is desired. The substrate elements are themselves overlapped and an impermeable coating is applied to the overlapping substrate elements to sealably bond the adjoining sheet components to one another and thereby define an assembled liner. The second rake surface is located more inward than the first rake surface and is inclined toward the lower surface at a second rake angle different from the first rake angle on the basis of the perpendicular plane.