130 millions years ago, birds have diverged from other archosaurs. Except the most primitive birds of the cretaceous, they lost the property to produce teeth. Tooth development requires complex epithelialmesenchymal interactions, which imply the expression of numerous genes, which begin to be well known. Four different experiments have permitted to obtain tooth rudiments in chick embryos. The association of oral chick ectoderm with mouse molar mesenchyme, the exposition of oral chick ectoderm to BMP's and FGF's, the transposition of mouse neural crest in young chick embryos, and the use of a Talpid mutation lead to tooth anlage development in the chick embryo.