Fluoride and urea chewing gums in an intra-oral experimental caries model.

The aim of the present investigation was to evaluate the effect of sugar-free chewing gums containing fluoride (F) and urea in an intra-oral experimental caries model. Placebo chewing gums (without any active ingredient) and no gum served as controls. Fifteen subjects participated in a cross-over, single-blind study. Demineralised enamel and dentine blocks were embedded in circular plastic discs and bonded to the buccal surfaces of the lower canines and first premolars. The discs were removed and analysed using transversal microradiography after each of the six 4-week periods during which the subjects used either test or placebo products or no product. The results revealed that frequent use of sugar-free chewing gum is sufficient to inhibit further demineralisation of previously demineralised enamel and dentine specimens in the oral cavity. Comparing F, urea and placebo gums, the data showed that there was little or no difference between the products, except for an inhibitory effect on the chewing side of the dentition after using F chewing gums.