The present invention relates to a coupling interface suitable for use with at least one pair of orthodontic aligners, retainers or positioners, comprising one upper jaw aligner, retainer or positioner and one lower jaw aligner, retainer or positioner, said pair of aligners, retainers or positioners comprising a polymeric material and tooth receiving cavities to accommodate teeth arranged in the said upper and lower jaws. The appliance comprises a set of at least two hinge units, each hinge unit comprising two joints each of which being engaged with one of the two aligners, retainers or positioners, the two joints further being pivotally connected to the distally opposing sections of a tube or shaft, wherein at least one of the joints is detachably engaged with the respective aligner, retainer or positioner
