Which substance is commonly used in whitening toothpastes for heavily stained teeth?

Hydrogen peroxide is widely recognized for its effectiveness as a bleaching agent in whitening toothpastes, especially for heavily stained teeth. It works by penetrating the enamel and breaking down stains present on the surface and within the tooth structure. This chemical reaction helps to lighten the color of the teeth, thereby making them appear whiter and brighter.

In contrast, while sodium bicarbonate (baking soda) and calcium carbonate both serve as mild abrasives in toothpaste formulations, their primary function is to assist in removing plaque and surface stains rather than providing a deep whitening effect. Silex, which is a form of silica, is often used in toothpaste for its abrasive qualities but does not have the same whitening capabilities as hydrogen peroxide. Therefore, hydrogen peroxide stands out as the most effective and commonly used substance for achieving noticeable whitening effects in heavily stained teeth within whitening toothpaste formulations.