This in situ study aims to investigate

• the protective potential of milk and fluoridated milk on erosive wear of enamel
• the protective potential of milk and fluoridated milk on erosive wear of dentin
• to compare to protective potential of milk and fluoridated milk with products containing casein phosphopeptide-amorphous calcium phosphate
• to compare the protective potential of milk and fluoridated milk with a fluoridated toothpaste or stannous-chloride containing fluoride solution (SnCl2/AmF/NaF)

Dental erosion is defined as the pathogenic, chronic, chemical removal of dental hard tissues due to the frequent contact to extrinsic or intrinsic acids. The dissolution process is determined by the pH, the chelating properties, mineral content and kind of acid, but in the same time modified by various biological (e.g. saliva, pellicle) and behavioural factors.

The anticariogenic properties of milk are widely investigated, but information of the effects of milk or milk components on the development of erosion are limited. It is suggested that the demineralisation process is reduced by the presence of calcium and phosphate, but also that casein proteins affect the demineralisation by adsorbing to the hydroxyapatite surface and inhibiting its dissolution. Initial studies suggest that milk is able to increase rehardening of acid-softened enamel, but information about the effects of milk on dentin erosion are not available yet. Particularly, the effect of fluoridated milk on dental erosion was not investigated yet.

In contrast, recent studies analysed the effects of products containing casein phosphopeptide-amorphous calcium phosphate (CPP-ACP) on erosion, as it is suggested that CPP-ACP promotes a supersaturated state and increased remineralisation of demineralised dental hard tissue. However, in situ studies on the effect of CPP-ACP on erosion are limited to one study, which compared microhardness of enamel after treatment with CPP-ACP and CPP-ACP and 900 ppm fluoride, but failed to use appropriate controls in form of other products containing calcium and phosphate or fluoride. In summary, the effects of milk, in particular fluoridated milk, and products containing milk proteins, such as casein phosphopeptide-amorphous calcium phosphate, on erosive wear were not analysed in an in-situ-model so far.

Inclusion Criteria:

• healthy volunteers

Exclusion Criteria:

• non-treated caries lesions
• orthodontic treatment which does not allow to wear an intraoral device
• hyposalivation
• allergy against milk or milk proteins