The aim of this study was to determine any existing difference in the amount of fluoride incorporated in the surface, body enamel and dentin of two groups of deciduous teeth, either exposed to pre- and postnatal fluoride supplements or to postnatal fluoride only. One hundred and eighty five subjects with intact deciduous incisors were selected from a randomized, double blind study of the caries preventive efficacy of prenatal fluoride (F) supplementation. Surface and body enamel samples were obtained by the acid etch biopsy technique. Dentin microsamples were obtained by drilling to a depth of 100 microm using the microdrill biopsy technique. It was concluded that fluoride exposure during the prenatal period offered no additional measurable fluoride uptake by dental tissues other than that attributable to postnatal fluoride alone. Copyright 2005 S. Karger AG, Basel.