Influence of Chewing Gum with Sodium Fluoride on the Human Tooth Enamel Fluoride Content in 13-Year-Old Children Affected by Caries

Abstract

The carious lesion is initiated by the production of organic acid, products of the carbohydrate metabolism by plaque bacteria and the subsequent dissolution of the enamel. Such a process is a dynamic one, and a number of factors must be considered. These factors vary from the type and relative amounts of microorganisms colonizing tooth surfaces to the chemical and ultrastructural properties of the enamel, what ultimately leads to the unique phenomenon of subsurface demineralization (1). Numerous authors have proved that hard dental tissues are permeable to certain sizes of molecules and ions. One of them can be fluoride. There is general agreement that availability of fluoride reduces caries. The beneficial influence of fluoride on caries has been confirmed in numerous studies (2). In spite of a vast amount of researches, the mode of action of fluoride as a caries preventive agent is still discussed. The most important of the current views seems to be that fluoride in the fluids surrounding the enamel crystals enhances the rate of the remineralization after the acid attack (3,4). The plaque fluid contains approximately 0.85 mmol/dm³ of calcium ions (5), and it has been suggested that calcium fluoride may be precipitated when plaque is exposed to fluoride present in mouthrinse solutions, toothpastes, or other fluoride-containing preparations used for caries prevention. The fluoride level in the oral fluids necessary for the saturation with respect to calcium fluoride is estimated to be approximately 0.30 mmol/dm³, assuming an ionized concentration of 0.50 mmol/dm³, similar to that found in the parotid saliva (6). This fluoride concentration may be compared to those found in the whole saliva ranging from 1.4 to 38 mmol/dm³ during the first minutes after administration of fluoride tablets, fluoride-containing chewing gums or dentifrices, or 1.2% fluoride solutions (7). The aim of the present study was to investigate the influence of a sodium-fluoride-calcium-gluconate-containing chewing gum on the human dental enamel fluoride content among children affected by advanced caries.