Fig. 2

Spatial and temporal correlation of sensory nerves distribution and alveolar bone formation during OTM. a Schematic representation of 10 g induced physiological orthodontic tooth movement (OTM) and sample collection. b, c Bite force (b) and pain threshold in ear-temporal region (c) of mice gradually decreased before the 3rd day of OTM and increased afterward (n = 5. The red p value indicates the difference of the OTM group). d Micro-CT (μCT) reconstruction and X-ray showed the distance of OTM and the bone formation on the tension side of the first molar. The red and yellow boxes represent tooth movement and the distal alveolar bone of the first molar, respectively, and are shown below two rows for enlarged display. e Quantification of first molar moving distance (n = 5). f–i μCT quantification of BV/TV (f), Tb.N (g), Tb.Th (h), Tb.Sp (i) of the first molar distal alveolar bone during OTM (n = 5). j, k Immunofluorescence showed the spatial co-localization of CGRP⁺ sensory nerves with Osx⁺ osteoprogenitors (j) and CD31⁺ endothelial cells (k) in the periodontal tissues during OTM (white arrows indicate CGRP⁺ sensory nerves). All the quantitative data in Fig. 2 is presented as mean ± SD, and Two-tailed Student’s t-test was used for comparison. *P < 0.05; **P < 0.01; ***P < 0.001