a-h: Progress of the lingual orthodontic treatment with the WIN appliance. Round SE-Niti archwires are inserted directly after indirect bonding (a and b). The rectangular SE-Niti archwires are straight in the lateral segments to prepare for space closure (c and d). The residual spaces are closed on the SS archwires with the help of power chains (e and f). For final torque control 0.018”x0.018” TMA archwires are used (g and h). The TMA archwires are individual in the lateral segments. No supplementary finishing bends were necessary in both arches.