Effect of fluoride on human dental pulp cells in vitro.

Human dental pulp cells were cultured in fluoride containing medium of various concentrations (0, 1, 2, 5, 10, 20, 25, 30, 40, 50, 60 and 80 ppm) in order to study the biological effect on the cells' proliferation and alkaline phosphatase (ALP) activities. It was found that fluoride at 5 ppm concentration significantly stimulated cell proliferation and ALP activity between 24 and 48 hours after exposure whereas at higher concentrations (40 - 80 ppm), fluoride significantly inhibited cell growth and ALP activity after 48 hours (Student's t test). The maximum effect was around 80 ppm. These observations suggest that fluoride, if used at a low concentration, may be a useful therapeutic agent for the treatment of pulpal disease by means of stimulating the proliferation and differentiation of dental pulp cells. At higher concentrations, it will have negative effects on this kind of cell.

Effects of lead on the proliferation, protein production, and osteocalcin secretion of human dental pulp cells in vitro.

Teeth have been recognized as providing a useful long-term record of lead (Pb2+) uptake. However, information regarding the effects of lead on dental pulp tissue cells that foster dentinogenesis is scarce. This study investigated the effects of lead on dental pulp tissue using human dental pulp fibroblasts in vitro. Dental pulp cells from the teeth of young patients (aged 17-24 years) were cultured and subsequently treated with lead glutamate. It was shown that, in serum-free conditions, all the tested concentrations of lead (4.5 x 10(-5) M, 4.5 x 10(-6) M, and 4.5 x 10(-7) M) significantly increased pulpal cell proliferation. In the presence of 2% fetal bovine serum, increasing cell proliferation was observed only after exposure to a lead concentration of 4.5 x 10(-5) M. However, protein, procollagen type I, and osteocalcin productions were significantly decreased. The alteration of cell population and protein production of affected human dental pulp shown in this study are toxic effects of the lead.