A method of reducing facial aging in a person, having an upper and lower jaw bearing anterior or posterior teeth, comprises: a) providing a mass produced universal dental appliance, which appliance comprises at least one part, the or each part intended in use to be in continuous contact with the teeth on either the upper or lower jaw, the or each part comprising an elongate structure at least a portion of which is formed of a durable, resilient, elastomeric material having a softening point in the range from 35 to 100.degree. C. and has a surface which in use is in continuous contact with the occlusal biting surfaces of at least two teeth on either the upper or lower jaw, and wherein said appliance has dimensions such that in use it provides a predetermined vertical separation of the jaws which is at least 3 mm beyond the normal resting position of the jaws; b) fitting said mass produced universal dental appliance to at least two teeth on either the upper or lower jaw of the individual; and c) exercising the lower jaw passively to allow the jaw to come to rest in a new resting position, is disclosed. An appliance for use in the method is also disclosed.