Your Teeth Are Almost as Strong as a SHARK'S!

The outermost layer of our teeth, known as enamel, holds the distinction of being the hardest substance in the entire human body. This remarkable durability stems from its composition, which is overwhelmingly mineral, primarily a crystalline calcium phosphate called hydroxyapatite. It is this dense, mineralized structure that provides our teeth with the incredible resilience needed to withstand the daily forces of biting and chewing, performing tasks comparable to materials like steel.

Interestingly, the formidable teeth of sharks share a similar mineral foundation (Review). Their outer layer, called enameloid, is also rich in calcium phosphate, specifically a fluoride-containing version known as fluoroapatite. While the specific chemical makeup differs slightly, studies have shown that the hardness of shark teeth is surprisingly comparable to that of human enamel. Both biological materials exhibit an impressive resistance to wear and tear, a testament to the evolutionary pressures that shaped these crucial feeding tools.

However, where sharks gain a distinct advantage is not necessarily in individual tooth strength, but in their unique biological system. Unlike humans, who have a limited set of permanent teeth, sharks continuously grow and replace their teeth throughout their lives. They can shed thousands of teeth, with new ones constantly moving forward from multiple rows to replace lost or damaged ones, sometimes in as little as 24 hours. This constant renewal ensures a perpetually sharp and efficient set of teeth, a stark contrast (Review) to human enamel, which, once damaged, cannot regenerate itself.