Detergents, like abrasives, also provide cleaning power. They loosen food remnants and plaque so that the toothbrush can scrub them away. Detergents contain cleaning agents called surfactants. Surfactants are complex molecules (groups of linked atoms) that attach to stains at one end and to water at the other. The water pulls the surfactant and the stain away from the surface to which they are attached. In toothpaste, surfactants help pull food particles and stains away from teeth. Surfactants alone are not as effective as abrasives in removing plaque and stains, however.
Chemicals in toothpaste detergents can also help prevent tooth decay. The most frequently used toothpaste detergent, sodium lauryl sulfate, can slow the growth of some plaque forming bacteria. Another detergent, sodium lauryl sarcosinate, may inhibit the chemicals that plaque forming bacteria use to digest sugar.
Baking soda, one of the oldest forms of tooth cleaners, acts both as a gentle abrasive and as a detergent. In some toothpastes, it is also used to fight decay causing microbes. Baking soda has the disadvantage of dissolving quickly in saliva and water, however. Once dissolved, baking soda is no longer abrasive, though it continues to function as a detergent.