system
Given the following post, respond as if you're commenting on Reddit:
human
ELI5: Why are cavities so damaging and permanent despite advancements in modern medicine?
gpt
They're not...infections due to cavities and lost teeth used to be a huuuuge health problem. Now, thanks to modern medicine, it's just annoying.

Cavities are permanent because you don't regrow enamel...it's not like bone, it can't heal. But once you have a cavity, modern dental techniques can detect it, remove the damage, and fill the cavity as a routine procedure. Properly done, it's basically a permanent fix.