Transport of various substances through human enamel and dentine

The penetration of 14C-labelled alcohols (methanol, ethanol, n-butanol), 14C-labelled carbonic acids (formic, acidic, propionic, valerianic, octanoic, malonic, succinic and lactic acid), 14C-drugs (procain, barbital), and 14C-sugars (saccharose, xylose) into about 800 human deciduous or permanent teeth, both healthy and carious, was investigated. Dental enamel up to the cemento-enamel junction was incubated at a pH-value of 5.0 or 6.8 for 1 or 24 hours. For measurement of radioactivity, the dentine of the root was obtained by trepanation. Between intact and carious permanent teeth only slight differences were observed in case of the diffusion of methanol and ethanol (2% of the incubation medium), while n-butanol penetrated the dentine to an extent of 4.2% at a pH of 5.0. The monocarbonic acids penetrated the enamel of healthy teeth within 24 hours to an extent of 6.6-19.2% of the content of the incubation medium, while the dicarbonic (succinic and malonic) acids reached amounts of 3.6 and 9.2%, and the percentage of lactid acid which penetrated the enamel reached 2.9%, respectively. Under all conditions tested, saccharose penetration was higher in carious than in healthy teeth (3.8 vs 6.5%). The highest uptake was found in experiments with barbital; it was more pronounced in deciduous than permanent teeth (16.2 vs 12.4%). The data could be of interest in the therapy of inflammatory and other processes of the pulp.