Abstract: An interocclusal dental appliance has a liner and an outer shell of a material harder than the liner. The shell extends around the liner through the occlusal surface, the buccal and lingual surfaces, and around an undercut edge of the liner mechanically to secure the harder shell and the liner, but to permit the teeth of the user to engage the liner. The method of producing the appliance includes making a mold of the teeth of a patient forming a liner with cavities complementary to the teeth and occlusal surface, and forming, over the occlusal surface of the liner, over the buccal and lingual surfaces of the liner and around a parimetric edge of the liner a shell of material harder than the liner.