Comparison of the in vitro permeability of human dentine according to the dentinal region and the composition of the simulated dentinal fluid

Abstract Objective . To compare the permeability of the occlusal and the cervical dentinal regions within the same tooth, which represent the bottom of Class I and V cavities, respectively, with two different compositions of perfusion fluid, in vitro. Methods . An occlusal and a buccal disc were cut from each extracted third molar at a level close to the pulp chamber. The convective permeability of the discs was measured in a fluid transport model using de-ionised water or 1:3 diluted bovine serum and the hydraulic conductance was determined. Results . The mean hydraulic conductance values of the occlusal and the buccal cervical human dentine to water were 0.069 and 0.047 μl min −1  cm −2  cm H 2 O −1 , respectively. When diluted bovine serum was used, the corresponding values were 0.036 and 0.012 μl min −1  cm −2  cm H 2 O −1 , respectively. Statistical analysis revealed no significant difference between the permeability of these two regions. The composition of the perfusion fluid significantly influenced the permeability of dentine. Conclusions . The occlusal and the buccal cervical regions of human dentine have similar permeability characteristics in vitro. There is a strong reverse correlation between the viscosity of the perfusion fluid and the perfusion through the dentine.