IN-VITRO MINERALIZATION IN BOVINE TOOTH GERM-CELL CULTURED WITH SINTERED HYDROXYAPATITE

Unerupted teeth were extracted from the mandibles of calves, and the enamel surfaces containing ameloblasts and cells of papilla layer were scraped off. Cells migrated from the fragments were transferred into culture flasks containing small bars of sintered hydroxyapatite, and the cultures were incubated long-term. Most of the cells showed a fibroblastic morphology, but some of the cells formed an epithelial cell nest. The fibroblastic cells grew steadily, but the epithelial cells showed poor growth. The fibroblastic cells formed multiple cell layers and were embedded in collagenous matrix containing type I trimer collagen. By 3 months, fibrous bands appeared on the surface of the cell layers and surrounded the bars of sintered hydroxyapatite. Such bands increased in size with incubation time. Mineral deposition was observed in the well-developed bands. The deposited crystals were found by the X-ray powder diffraction method to be hydroxyapatite; the Ca/P molar ratio of 1.49 was determined by the ICP method. These results indicated that cells of papilla layer have the capacity to mineralize in vitro in the presence of sintered hydroxyapatite.