[Fine structure of the root resorption of human deciduous tooth]

During growth and development of the gnathic bone in infants, it is not possible to observe the processes of resorption of the bone and deciduous tooth root, bone formation and calcification of the permanent teeth separately. In the gnathic bone of infants where a normal balance exists between formation of new tissue and resorption, the formative bone tissue is closely related to the cells which give rise to the deciduous and the permanent teeth. We used a scanning electron microscope to observe the fine structure of the root resorption of the deciduous teeth, using root deciduous teeth extracted from humans. Large and small plate-shaped absorbed fossula were found together with projecting dentinal fiber tubuli in the dentinal resorption cavity of the deciduous tooth root. Odontoclasts with a round form supported and covered by fibrous connective tissue were also observed. Furthermore, when the fibrous tissue was removed washed out, an arrangement of calcified collagen fibers (similar to stromal tissue) was found in the cavity. On the absorbed cementum surface a plate-like resorption cavity had formed. The surface was covered by fibrous connective tissue with a regular pattern. The round and oval odontoclasts were surrounded by thick vascular-like connective tissue. High levels of P and Ca were found in the dentinal absorption cavity by X-ray analysis and Al, Mg, Na and Zn were also found. S, P, Ca and Zn were found in the odontoclasts Ca, P, Mg, Na and Zn were found in the cementum resorption cavity.