Probing the future in functional soft drinks on the nanometre scale-towards tooth friendly soft drinks

Soft drink and confectionary induced demineralisation of dental enamel has increased sharply over the last decade and has replaced dental caries, as the number one reason for tooth decay in younger people. The tooth demineralisation process is sometimes called erosion, which is defined as the chemical dissolution of dental enamel without bacterial involvement. During erosion, calcium and phosphor are dissolved from the enamel which eventually leads to a collapse of the enamel surface structure and loss of the outermost enamel layers. The enamel erosion process caused by a large number of conventional soft drinks may be reduced by understanding the physical and chemical processes during the demineralisation process and by using this knowledge in the design of new complex functional soft drinks. A key factor for this seems to be to understand the early stages of enamel demineralisation at the tooth-soft drink interface as at this stage the demineralisation process was assumed to be reversible by remineralisation. Nevertheless, early stages of enamel demineralisation were not accessible for investigation until recently due to a lack of suitable technology. This review paper discusses recent progress to explore the early stages of soft drink induced enamel demineralisation using nanoanalytical/nanomechanical approaches, such as scanning probe microscopy and nanoindentation. The results of the in vitro and in situ studies lead to a design recipe of a new functional soft drink, which may exhibit substantially lower erosion effects than conventional soft drinks.