Dentin permeability: a comparison of functional versus anatomical tubular radii

Two independent techniques (filtration and surface tension) were developed to measure the functional tubular radii of 11 dentin and 2 glass discs. Anatomic radii were determined using SEM for comparative purposes. The functional radii of the dentin discs ranged from 5 to 40% of the anatomic radii. This differences was due to the fact that SEM visualizes only the surface while the functional techniques measure the radii within dentin tubules. It is concluded that the functional methods are preferred whenever the dynamics of fluid flow through dentin are under consideration.