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 ³H₂O 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 ³H₂O 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.