Comparison of Diffusion of Different Microbial Growth Factors, Alone and in Combination, through Extracted Human Teeth

¹ U.S. Naval Dental School, National Naval Medical Center, Bethesda, Maryland

The diffusion of microbial growth factors through 18 extracted teeth (unerupted third molars) was measured by means of bioassay. It was found that L-tryptophane, niacin, pantothenate, and folic acid diffused from the pulp sides to the crown sides of teeth at a constant, measurable rate, whether diffused singly or in combination. Diffusion through drilled teeth was from six to twenty-three times greater than through intact teeth. Each single growth factor diffused at approximately the same rate whether diffused alone or in combination—except for folic acid in intact teeth. Significant differences were observed between diffusion ratios of the four growth factors. Finally, significant differences in diffusion ratios were observed between individual drilled teeth. These differences appeared to be correlated principally with the depth of dentin through which the diffusion was occurring.