Morphometric and immunohistochemical investigation of tooth development in rats prenatally exposed to ethanol

The purpose of this study was to clarify the effect of ethanol on rat molar tooth development. Pregnant rats were fed 25%-ethanol solutions or ethanol-free water up to delivery, and tooth germs, as well as fully developed teeth, obtained from the offspring (ethanol-exposed rats or control rats) were subjected to morphometric analysis and immunohistochemistry. No significant differences were observed in terms of tooth size between the ethanol-exposed and control rats. Moreover, no abnormalities in cusp number, form or dental surface structure was noted in the ethanol-exposed rats. In the ethanol-exposed rats, the tooth development showed a slight retardation in comparison to the controls. Morphological alteration in tooth germs was not observed in the experimental rats. Both bone morphogenetic protein-4 and basic fibroblast growth factor-2 were immunolocalized in the cells composing the tooth germs in the ethanol-exposed rats. No differences, however, were found in immunostaining intensity between the ethanol-exposed and control rats. Taken together, the results indicate that the effect of ethanol on tooth development was weaker than expected in the rat FAS model.