The aim of the present study was to investigate the influence of surface enamel on the susceptibility of the tissue to acid attack by exposing both unabraded and abraded surfaces to an identical artificial caries system. Enamel from teeth developed in ‘low’, ‘optimal’ and ‘high’ fluoride areas was used for the experiment and the fluoride content of the surface enamel under test was sampled. Results confirmed the protective nature of surface enamel and the resistance of the fluorosed tissue to the artificial caries process. However, no difference was found between enamel from low and optimal fluoride areas in either the fluoride content of the surface enamel or its susceptibility to acid attack. It is, therefore, suggested that the cariostatic effect of fluoride in optimal fluoride areas may well be a result of its top