The primary and mixed dentition, post-eruptive enamel maturation and dental caries: a review

Between birth and the age of 12 years, the mouth is in flux, through the eruption of the primary teeth, post-eruptive maturation, and then the mixed dentition period. The latter phase is perhaps the most complex of all, with concurrent exfoliation of the primary dentition, eruption of the permanent dentition and the post-eruptive maturation of the permanent teeth. The permanent teeth are often at highest risk of caries during this period for at least two reasons. Erupting teeth are difficult to clean, as they are not yet fully aligned with their neighbours, and, in any event, cleaning may be avoided completely because of tender gums. In the months and years following eruption, primary and permanent enamel undergo post-eruptive maturation, which is thought to reduce vulnerability to caries. During post-eruptive maturation, the enamel surfaces accumulate fluoride and metal ions, become harder, less porous and hence less caries-prone.