Caries preventive mechanisms of fluoride in milk and fluoride in water. Plasma fluoride profiles. Direct comparisons of the plasma fluoride profiles in fasting human subjects

Biological plausibility is an essential stage in establishing the therapeutic value of a preventive or curative agent. Ultimately, efficacy and effectiveness are tested in clinical trials and community programme evaluations, which provide reassurance and guidance for potential users. Almost invariably, biological plausibility is demonstrated before clinical evaluations are sanctioned and undertaken. Biological plausibility can be established through a variety of investigations relevant to the disease or disability. As far as dental caries is concerned, the biological process is so well known so that there is little difficulty in accepting a variety of models which may be used to demonstrate biological plausibility. These models include systemic parameters (eg. plasma and urine) and intra-oral parameters (eg. saliva, plaque and enamel). This applies particularly strongly to the preventive agent fluoride since its biological effects have been studied very extensively.