Studies on fluoridated toothpicks.

The aim of this thesis was to evaluate the wooden toothpick as a vehicle for the delivery of fluoride to the approximal area. After two minutes use in vivo, the release of fluoride from the pointed section of a toothpick impregnated in 4% NaF was estimated to 0.15 mg. Toothpicks produced similar or somewhat higher fluoride concentrations in the approximal area compared with other fluoride-containing products, like dentifrice, mouthrinse solution and tablet. The mean fluoride concentration in an approximal area treated for two minutes with a toothpick impregnated in 4% NaF was around 11 mM/l. Toothpicks impregnated in 4% NaF, 8% SnF2 or 2% chlorhexidine had an effect on the proportion of mutans streptococci and on the decline of pH in dental plaque, but it was small and only of short duration. The recolonization of mutans streptococci was, however, slower after using the SnF2- and chlorhexidine-impregnated toothpicks than after using the NaF- and non-impregnated toothpicks. The effect of fluoridated toothpicks on the degree of de- and remineralization of enamel and dentine was measured using transversal microradiography in an in situ study. Four weeks' use of toothpicks, especially of NaF-impregnated toothpicks, reduced the degree of demineralization of enamel and dentine at approximal sites. Secondary ion mass spectrometry was also used to determine the fluoride content in the outer surface of dentine, which increased more than 10 times after using fluoride toothpicks compared with non-impregnated toothpicks. In a second in situ study, 4% NaF-, 2% chlorhexidine- and non-impregnated toothpicks had a similar effect on sound and demineralized enamel and on demineralized dentine. However, the NaF toothpicks were superior in terms of their effect on sound dentine. The effect on mutans streptococci and plaque-pH, on the other hand, was the same for all three types of toothpicks. The main conclusion from this thesis is that the wooden toothpick is a suitable vehicle for the delivery of fluoride to the approximal area.