Tooth enamel is the hardest substance in the human body, but, until now, no one knew how it managed to last a lifetime. The authors of a recent study conclude that enamel's secret lies in the imperfect alignment of crystals. Using new imaging technology, scientists have unlocked the secrets of enamel.

If we cut our skin or break a bone, these tissues will repair themselves; our bodies are excellent at recovering from injury.

Read more at Medical News Today.