A tongue cleaner (also called a tongue scraper or tongue brush) is an oral hygiene device designed to clean the coating on the upper surface of the tongue. While there is tentative benefit from the use of a tongue cleaner it is insufficient to draw clear conclusions regarding bad breath. A 2006 Cochrane review found tentative evidence of decreased levels of odor molecules. The large surface area and lingual papilla are anatomical features of the tongue that promote tongue coating by retaining microorganisms and oral debris consisting of food, saliva and dead epithelial cells. Tongue cleaning is done less often than tooth brushing, flossing, and using mouthwash.