Abrasive agents make up the bulk of the ingredients in toothpaste, and their general purpose is to assist in removing plaque from teeth. Among these abrasives are minerals such as mica, various silicas, limestone and aluminum oxide.
While the initial concept of abrasive materials to be applied to one's teeth in the form of early toothpaste (thought to be established in Ancient Greece) involved crushed animal bones and oyster shells, modern toothpaste leans more towards the science behind certain minerals to get the job done. Silica and limestone, when ground, make excellent tools for scrubbing plaque off the teeth due to their coarseness. Mica, a mild abrasive when extracted from rocks and ground, also provides the glistening appeal to toothpaste products.
The white pigment of toothpaste can most commonly be attributed to Titanium Dioxide, produced from ilmenite ore, and is also used to make white paint. Lastly, a fine gel abrasive, such as silica, is also added into most toothpastes. Hydrated silica (Diatomaceous earth - coined "tooth powder") mixed with calcium carbonate is another abrasive said to remove plaque. Hydrated silica is a mineral formed from silicon dioxide and is an odorless, tasteless, white gelatinous substance that is found in most of today's modern toothpastes.