Abstract: The invention concerns a mounting device for a pair of orthodontic retainer elements intended for attachment to a pair of adjacent teeth in a dental arch during passive orthodontic treatment. The retainer elements include approximal surfaces formed complementary to each other so as to form contact surfaces capable of stabilizing each other when the pair of retainer elements is attached to the pair of adjacent teeth, thereby also stabilizing the pair of teeth. The mounting device comprises a jig to which the pair of retainer elements is releasably connected and is maintained in a specific spatial relationship, which allows the approximal surfaces to form the stabilizing contact surfaces when mounted on the pair of teeth. The invention also concerns a method of maintaining a correct spatial relationship between the pair of retainer elements, especially when attaching them to the pair of teeth.