Characterization of an in vitro dentin barrier test using a standard toxicant

To characterize a new artificial pulp chamber using bovine dentin, the influence of different phenol concentrations on the cell reaction was evaluated. Bovine dentin slices of 100, 200, 300, 500, and 700 microns were cleaned, sterilized, and mounted between two 5-mm-thick glass plates with a borehole of 5 mm in diameter. L-929 mouse fibroblasts were seeded into the "pulpal" part of the device and incubated for 24 h. Different concentrations of a phenol solution as a standard toxicant were applied to a sterile cotton pellet in the "cavity" side of the device. After incubation for 24 h, the cytotoxic reaction was evaluated by cell counting after vital staining with fluorescein diacetate and related to the negative control. A dependency of the cytotoxic reaction on the concentration of the standard toxicant and on the thickness of the dentin slice was demonstrated. The simple dentin barrier test using bovine dentin may be a suitable alternative to other more complicated procedures using human dentin.