ULTRASTRUCTURAL INVESTIGATION OF THE ROLE OF THE ODONTOBLAST IN MATRIX CALCIFICATION USING THE POTASSIUM PYROANTIMONATE OSMIUM METHOD FOR CALCIUM LOCALIZATION

The localization of calcium in the odontoblast and odontoblast process related to forming dentine was investigated using the potassium pyroantimonate osmium method. Precautions were taken to minimize artifacts; the specificity of the reaction for calcium was confirmed by appropriate controls and energy dispersive analysis. Calcium was not removed by a high extracellular concentration of potassium; calcium introduced into the tissue was localized at specific sites within the cells, suggesting that the calcium is bound, probably to organic macromolecules, and released during the fixation process. In the odontoblast, calcium was localized within the vesicles of the Golgi apparatus, including abacus bodies, as an evenly distributed calcium pyroantimonate precipitate. In the odontoblast process, vesicles were concentrated peripherally and often associated with numerous coated vesicles. Within the vesicles, the calcium pyroantimonate precipitate was usually polarized. The mechanism by which this calcium is released from the cell remains uncertain. © 1979.