The central nucleus of the amygdala lesion attenuates orthodontic pain during experimental tooth movement in rats

INTRODUCTION: Orthodontic pain is the most common adverse side effect reported in the context of tooth movement. Given its central role in processing pain and negative emotion, the central nucleus of the amygdala (CeA) is thought to be a key site involved in orthodontic pain sensation. METHODS: In the present study, we therefore explored whether the CeA is involved in contributing to orthodontic pain in a rat model of tooth movement. For this study, we utilized adult male rats with bilateral sham or electrolytic CeA lesions (400 μA; 25 s), and then we analyzed face grooming behavior as a measure of pain sensation. RESULTS: Through this approach, we found that there were time‐ and force‐dependent factors influencing pain levels in these rats. We further found that bilateral CeA lesions markedly reduced tooth movement‐induced orofacial pain and that unilateral CeA lesions did so to a lesser extent. CONCLUSIONS: As such, these results suggest the CeA is a key area of orthodontic pain, with the results of this study highlighting potential avenues for achieving pain relief in those suffering from orthodontic pain.