How can you regain enamel?

You can regain enamel by drinking milk anf using toothpastes with high concentrates of fluorides and calcium I hope this helps Glad to help Jordan @Jordan
You simply cannot regrow enamel. It is a substance, not a bone. Calcium helps make your bones stronger, and there are other sources besides milk. As for the toothpaste, you are thinking of whiteners or those products that claim they can protect your enamel. But the base line is, you cannot regrow enamel.