FACTORS INFLUENCING PENETRATION OF SYNTHETIC DETERGENTS AND CERTAIN OTHER COMPOUNDS INTO DENTAL PLAQUE MATERIAL

¹ Walter G. Zoller Memorial Dental Clinic and the Department of Medicine, University of Chicago, Chicago, Ill.

An investigation has been made of the rate of penetration of several different types of compounds into dental plaques. Experiments with powerful antibacterial compounds, e.g., germicidal synthetic detergents, demonstrated that the metabolic activity of the intact plaque is inhibited considerably more slowly than that of an equivalent quantity of homogenized plaque material. It was found that even very diffusible compounds such as glucose and urea entered intact plaques rather slowly. These different types of compounds all appear to penetrate the plaques entirely by passive diffusion. To achieve rapid permeation of thick plaques, a high concentration gradient must be established. A technique was developed for laying down "artificial plaques" of definite thickness in vitro. These preparations proved to be very useful for experiments on the ability of various compounds to permeate plaque material. By means of this technique it was found that synthetic detergents, urea, and glucose penetrate in direct proportion to their concentration and time of exposure, and inversely with the thickness of the artificial plaques.