Minutus

In an adult with very thin tooth enamel (probably partly congenital, but
also partly from sucking lemons as a child), is there any possibility of
building up the enamel with remedies? Or is it too late, since the teeth
are already formed? The only specific symptoms I'm aware of are sensitivity
of the teeth to many things, and they appear slightly discolored, which
she's been told is because of the thin enamel.

Thanks,
Shannon