The set has two rigid connecting rods (20, 20') laterally connecting lateral pivots (33) of corresponding dental trays of the set and arranged in vestibular position. The pivots are arranged perpendicular to a median plane (P) on each dental tray. Each connecting rod has a central part (21) defining an axis, and end tabs (22) defining planes that are distinct and parallel to the median plane. The axis of the central part sections the planes of the end tabs at a non-zero angle.
