[HiTech RedNeck]

Or, the cavity has to get into the pulp before this treatment will do anything? But once it does, it will grow back the tooth, enamel and all?

[Right Wing Assault]

Misleading headline, poorly-written misleading article. Otherwise, it was great!

[Carry_Okie]

Or, the cavity has to get into the pulp before this treatment will do anything? But once it does, it will grow back the tooth, enamel and all?

Unlikely. IIRC, the dentin is a high-density variant of cancellous bone originally built from the interface with the enamel downward, while the enamel is laminar bone built the other way from the outside. The process involves two different kinds of cells.

That's the cool thing about composite structures, and the difficulty in replicating them.