BDNF and periodontitis: This finding is consistent with other studies’ findings.[37] Additionally, the transcription level of CGRP is higher than that of SP in periodontium.[38] In the trigeminal ganglia, CGRP+ neurons are also denser than SP+ neurons.[39] In our study, the bone‐forming capacities in diabetic mice with periodontitis were significantly promoted by the local application of CGRP, without the involvement of other neurotrophins and neuropeptides.