Effects of pulsatile versus non-pulsatile pulpal pressure simulations on diffusional transport across human dentine in vitro

The influence of a simulated pulsatile pulpal pressure on the diffusion of NaCl through slices of human dentine (n = 12) was evaluated in vitro. The average hydraulic conductance of the slices of dentine was 0.0131 ± 0.0031 μl/cm2 per min per cmH2O(x±SD). A 1 mol/1 NaCl solution was placed on one side of the slices of dentine and deionized water on the other side. The time needed to reach a steady state and the quantity of NaCl that diffused through the slice were successively measured on the same slice of dentine, under three conditions: without pressure simulation, with a static pressure of 1.5 kPa, and with a pulsatile pressure varying from 1.2 to 1.8 kPa. The pressure was applied to the deionized water. When a static pressure was applied, the time required to reach a steady state increased from 24 to 30 h. When a pulsatile pressure was applied the time required to reach a steady state decreased from 24 to 12 h. No statistically significant difference was found between the quantity of NaCl that had diffused when the steady state was reached.