samzenpus from the thank-you-science dept.
sciencehabit writes "Don't feel inadequate. Even though your teeth are largely composed of a mineral softer than that found in sharks, new tests suggest that they're just as tough. In sharks, the material coating the teeth is largely composed of fluoroapatite, a fluoridated phosphate mineral that in its pure form is harder than the hydroxyapatite found in the enamel of human teeth. But by pressing tiny metallic pyramids into the surfaces of teeth from a shortfin mako shark and a tiger shark, researchers found that the enameloid coating on shark teeth is no harder than that of the enamel on a human wisdom tooth. The teeth are, in fact, of comparable hardness because their surfaces aren't pure mineral but instead are made of mineral crystals bound together with proteins so that the material doesn't shatter under a sudden impact."
Stinginess with privileges is kindness in disguise.
-- Guide to VAX/VMS Security, Sep. 1984