Fig. 1

A 60 g orthodontic force is optimal to induce tooth movement. A, B The distance from the distal ridge of the first molar to the mesial ridge of the second molar is considered the tooth movement distance. The movement distance of the first molar increased in a force-dependent manner and reached a peak at 60 g (P < 0.01). When the orthodontic force was greater than 60 g, the tooth movement distance decreased. Red dotted lines indicate the tooth movement borders. All results are representative of three repeated experiments. *p < 0.05; **p < 0.01