Why can a broken bone heal but chipped tooth enamel never grows back?
Your body builds the hardest thing it owns - then throws away the tools to ever build it again.
Tooth enamel is the hardest tissue in the human body, about 96% mineral. But the cells that make it, ameloblasts, die once the tooth comes in. Enamel has no living cells of its own, so unlike bone or skin it can never grow back. What is lost stays lost.
Crack a tooth biting an olive pit in your bun rieu and that chip is permanent - a dentist fills it with material, the enamel itself never returns.
Protect enamel like a one-time gift: once worn or chipped, your body cannot remake it.
Knowing enamel never regrows changes how you treat acidic drinks, hard chewing, and skipped brushing - prevention is the only repair.
Hardest tissue, no spare cells - enamel is a one-and-done build.
Learn the idea and practice English at the same time.