Figure 5.

Schematic illustration showing how to prepare dentine disks (a) and how dentine permeability was measured by the fluid filtration system (b). Each dentine disk was placed in a device that allowed the standardization of exposed dentine area for filtration of deionized water by using pairs of rubber “O” rings. Then hydrostatic pressure of 10 psi was applied and the rate of fluid movement across the disk was measured by following the progress of a small air bubble in a micropipette with a millimeter scale.