Surfactants (detergents) create the foaming commonly associated with dentifrices. They aid in the cleaning process by helping to loosen plaque and debris. Sodium lauryl sulfate (SLS) is the surfactant most commonly used. SLS and other surfactants have been associated with the promotion of aphthous ulcers (canker sores) in a very small number of susceptible individuals. Surfactants also provide emulsion stability for the flavoring system. Without the surfactant in the toothpaste the flavor oil would not stay suspended in the product, causing oil separation from the product.