We study a subdiffusion-reaction system with initially separated reactants in the case where one of the reactants is static. Using the scaling method we show that the reaction front x_f evolves in time according to the power law x_f\sim t^{\alpha /2} where \alpha is the subdiffusion parameter. Comparing the theoretical formula with the experimental data we find that the transport of acids molecules inside the tooth enamel during the caries progress is of subdiffusive character.

PACS numbers: 82.33.Ln, 02.50.Ey