A mass produced universal dental appliancee (1) comprises two parts, the parts intended in use to contact the posterior teeth on respective opposite sides of either the upper or lower jaw, each part comprising a composite structure comprising: i) a first layer (2) formed a durable, resilient, elastomeric material having a softening point in the range from 35 to 100.degree. C. and which in use contacts and grips the occlusal biting surfaces of the posterior teeth; and ii) a second layer (3) formed from a durable, non-deformable material having a softening point over 100.degree. C. and which in use provides a bite plate; wherein the second layer of each part is provided with a protrusion (5), formed of durable, non-deformable material having a softening point over 100.degree. C., which extends from at least 2 mm up to 20 mm from the surface (4) of the bite plate away from the first layer and which is positioned such that in use the protrusion extends from the surface of the bite plate above at least a part of the first and/or second molar teeth which are in contact with the first layer. The appliance is useful in a method for reducing facial aging.