An orthodontic appliance is described which comprises an upper element 10 and a lower element 12, wherein at least one of the upper and lower elements 10, 12 takes the form of an active appliance, and wherein each of the upper and lower elements 10, 12 includes, on or associated with a surface thereof facing towards the other of the upper and lower elements 10, 12, an engagement member 18, the engagement members 18 being positioned such that, in use, the engagement member 18 associated with the lower element 12 is engageable with the engagement member 18 associated with the upper element 10 to urge the lower element 12 towards a desired position relative to the upper element 10.
