Spatiotemporal Dynamics Of Adjacent Teeth Post-Extraction In Rats

This study aimed to elucidate the spatiotemporal dynamics of adjacent teeth post-extraction and the METTL3-CTSK axis's role in a rat model. Male Wistar rats (n=24, 6 weeks old) underwent mandibular second molar (M2) extraction to quantify 3D positional changes of adjacent molars (M1, M3) via longitudinal Micro-CT imaging (0, 8, 16 weeks post-extraction), approved by Ethics Committee. Histological analyses (H&E, Masson’s trichrome, Sirius Red, TRAP staining, IHC, IF) were employed to observe periodontal ligament space(PLS), fibers, osteoclast activity and expressions of METTL3 and CTSK(4 weeks post-extraction). In vitro, osteoclast differentiation of RAW264.7 cells was induced by RANKL. SAH, a specific METTL3 inhibitor, was used to evaluate the roles of the METTL3-CTSK axis in osteoclast activity and bone resorption. Micro-CT revealed a 61.4% reduction in M1-M3 horizontal distance within the first 8 weeks post-extraction, alongside progressive tilting and vertical bone loss(p<0.05). Histology revealed the distal PLS of the mesial root of M1 was significantly narrower than the mesial PLS (p<0.05), newly formed transseptal fibers connecting M1 and M3, METTL3 and CTSK colocate in TRAP-positive osteoclasts. In vitro, western blotting and bone resorption assay demonstrated the SAH suppressed METTL3 expression, thereby downregulating CTSK levels and inhibiting bone resorption (p<0.05). Tooth extraction led to significant changes in the extraction space and adjacent teeth. Targeting the METTL3-CTSK axis may provide a novel strategy to mitigate pathological tooth movement.