Hematopoiesis and osteoclastogenesis do not occur in the dental pulp. (A–E) Immunohistochemistry for a mandible, including first and second molars at P18. CD45⁺ HCs and CatK⁺ osteoclasts were detected in the alveolar bone marrow (BM) but not in the dental pulp (DP). (F) Schematic diagram depicting the structural and cellular differences between BM and DP. Scale bars: 200 µm (A); 20 µm (B–E).