Abstract
To clarify the mechanism of root resorption in human deciduous teeth, we examined the activity of tartrate-resistant acid phosphatase (TRACP-ase), a marker enzyme for osteoclats, in 32 human deciduous teeth. After detecting the TRACP-ase activity by the azo-dye method, the sections were observed by light microscopy or confocal laser scanning microscopy (CLSM). At the early stage of root resorption, week TRACP-ase activity was detected in the odontoblasts only by CLSM. In the teeth undergoing root resorption, TRACP-ase activity was detected by CLSM in the odontoblasts located far from the resorption site. In the odontoblasts near the resorption site TRACP-ase activity was intense enough to be detected by light microscopy. The most intense activity of TRACPase was observed in odontoclasts and in the dentinal tubules opening onto the resorptive lacunae beneath odontoclasts.
These findings suggest that odontoblasts also involve during the initiation of root resorption, and the dentine matrix under the odontoclasts is degenerated by TRACP-ase secreted from odontoclasts into the dentinal tubules.
