An appliance for use in a method of reducing facial aging and/or oral parafunctional activity e.g. bruxism, 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: iii) a first layer (2) formed of a durable, resilient, elastomeric material comprising a cured thermoset rubber and which in use contacts the occlusal biting surfaces of the posterior teeth and iv) a second layer (3) formed of a durable, non-deformable material having a softening point over 100°C and which in use provides a bite plate wherein the second layer of each part, that has a substantially planar first surface, is provided with a protrusion (5), formed of durable, non-deformable material having a softening point over 100°C, which extends from at least 2mm up to 20mm from a second surface (4) of the second layer (3) away from the first layer (2) and which is positioned such that in use the protrusion extends from the surface above at least a part of the first and/or second molar teeth which are in contact with the first layer. A method of making the appliance and a kit of parts is also disclosed, as are several methods of use of the appliance.La présente invention concerne un appareil destiné à être utilisé dans un procédé de réduction du vieillissement facial et/ou dune activité parafonctionnelle orale, par exemple, du bruxisme, ledit appareil comprenant deux parties, les parties étant destinées à être utilisées en contact avec les dents postérieures des côtés opposés respectifs de la mâchoire supérieure ou de la mâchoire inférieure, chaque partie comprenant une structure composite : iii) une première couche (2) formée en un matériau élastomère, résilient et durable, comprenant un caoutchouc thermodurcissable durci et qui, durant lutilisation, est en contact avec les surfaces masticatoires occlusales des dents postérieures et iv) une seconde couche (3) formée
