Green tea catechin at a daily intake level suppresses root resorption while maintaining intrusive tooth movement in rat model

External apical root resorption (EARR) is a common complication of orthodontic treatment. Nevertheless, effective preventive strategies have not yet been established. Here, we demonstrated that administration of green tea catechin (epigallocatechin gallate: EGCG), at concentrations equivalent to habitual human daily intake when adjusted for rat body weight, prevented root resorption while preserving tooth movement in rats. An L-loop orthodontic appliance was used to induce vertical intrusive tooth movement for the maxillary first molar; EGCG was administered at doses of 1 and 2 mg every other day for 14 days (without EGCG for control). Tooth movement and root resorption were assessed using micro-computed tomography (µCT) as well as histological staining [hematoxylin and eosin (H-E) and tartrate-resistant acid phosphatase (TRAP)]. Despite no impairment in tooth movement in all groups, root resorption was significantly suppressed in the EGCG-administered groups. These findings suggest that habitual consumption of tea containing EGCG at daily concentrations may provide safe and effective strategies for orthodontic treatment.