[Study of the permeability of oral leukoplakia].

The significant increase in the mortality rates of oral carcinoma speeded up the research on the mechanisms of tumor promoting and inhibiting factors. Results of previous studies in the USA showed different permeability between keratinized (hard palate, gingive) and non-keratinized (floor of the mouth) regions of the oral mucosa, and a corresponding difference in lipid composition. Aim of this study was, to compare the permeability and lipid composition of leukoplakia of the oral mucosa with healthy specimens from the same region, in order to assess a possible enhancement or inhibition in the barrier-function, in cases of pathological keratinization. Results of the measurements showed, that hyperplastic leukoplakia areas were more permeable for the NNN carcinogens contained in tobacco, and even clinically healthy sites showed a higher permeability, that oral mucosa of non-smokers. These data together with the results of lipid analysis, point to the possible generalized changes--caused by smoking--in the oral cavity, even before the appearance of clinical signs.