Fig. 1

The diagrammatic sketch of this mouse incisor movement model. (1) Ligature A was threaded through the proximal space between bilateral maxillary incisors, then ligated at the neck of the incisors. (2) The ligature B was fixed on the distal side of the maxillary incisors by ligature A. (3) The Ni–Ti orthodontic wire was fixed on the distal surface of the maxillary incisors by ligature B. (4) The Ni–Ti orthodontic wire became U-shaped, and the “U-shaped bottom” was located between the first molars