A literature overview on the results of epidemiological studies focused to defining the period of child’s life, when developing enamel of permanent dentition is the most susceptible to be influenced by different impairing factors. The so called critical developmental period for the enamel of frontal permanent teeth spanns between the half year and the 4th to the 5th year of child’s life. It is necessary in the above period to manage carefully fluoride supplemen- tation in prevention of dental caries owning to the preventing the development of non-carious impairments of the enamel.

        Key words: enamel – permanent dentition – critical developmental period – fluoride