Teeth cannot produce enamel. Enamel is not a living tissue and it was produced by cells outside of the tooth in a coral-like manner. In order to grow a new tooth, you need it to be fully surrounded by specialized living tissue for the whole growth cycle.

PS: I honestly expected something like this to come out of bioelectric computation research, but progress seems slower there. Or rather knowledge and techniques in other fields is reaching critical mass, giving us these advances.