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

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 mul min(-1) cm(-2) cm H2O-1, respectively. When diluted bovine serum was used, the corresponding values were 0.036 and 0.012 mul min(-1) cm(-2) cm H2O-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. (C) 2002 Elsevier Science Ltd. All rights reserved.