The effect of hyper-vitaminosis a on the development of rat tooth germs in tissue culture

Pairs of first molar tooth germs from 17-day rat embryos were cultured in vitro , one member of the pair having additional vitamin A added to the medium on which it was grown. The germs cultured on hyper-A medium were smaller than the control teeth, and lagged in cusp development. The histodifferentiation of the enamel organs was severely affected, but the dental papillae showed less differences. The changes were almost completely reversible up to 7 days of culture.