Calcium ion transport kinetics during dentinogenesis: effects of disrupting odontoblast cellular transport systems.

Due to strongly discrepant results in the literature, controversy exists about the timing of the transport of Ca2+ ions to the mineralization front during dentinogenesis and the role of the odontoblasts in this transport. The present study gives evidence, by means of autoradiography as well as by a radiochemical technique, that the transport time for Ca2+ ions into the dentin mineral phase is about 10-15 min in the rat incisor. The results also show that technical factors, such as mode of tracer injection and the use of perfusion fixation, may influence the results more or less strongly. Finally, by disturbing odontoblast microtubules, involved in intracellular transport processes, and by blocking odontoblast calcium uptake channels by nifedipine and neomycin, the Ca2+ ion transport into dentin mineral was found to be strongly impaired. This may be taken as an indication that transcellular calcium transport mechanisms have a role during dentinogenesis.