Effects of the degree of tubule occlusion on the permeability of human dentine in vitro

The effects of changes in the nature of dentine surfaces on the permeability coefficients of 3H 2O and 131I-albumin were determined in vitro. From these data, diffusional surface areas were calculated. The dentine surface was altered from a highly-polished surface to a bur-roughened surface, to an acid-etched surface and to an oxalate-treated one. The diffusional surface areas for 3H 2O and 131I-albumin were: 1.72, 0.74; 1.86, 0.68; 7.89, 6.30; 2.24, 1.44 per cent, respectively. A second, independent technique based on measuring the volume of water occupying the tubules gave a mean surface area of 10.2–10.5 per cent. The increase in tubular surface area available for diffusion after acid-etching could be reversed by treating the surface with oxalate.