szkliwo
Szkliwo is the Polish word for enamel, referring to the hard, outer layer of a tooth. It is the hardest substance in the human body, composed primarily of hydroxyapatite, a mineral form of calcium apatite. This mineral structure gives enamel its remarkable strength and resistance to wear and tear. The outermost layer of the crown of a tooth, the enamel, is translucent and its color can range from bluish-white to yellowish depending on the individual's genetics and the thickness of the enamel.
Despite its hardness, enamel does not contain living cells and therefore cannot regenerate once it is damaged