The toothbrush is an oral hygiene instrument used to clean the teeth and gums that consists of a head of tightly clustered bristles mounted on a handle, which facilitates the cleansing of hard-to-reach areas of the mouth. Toothpaste, which often contains fluoride, is commonly used in conjunction with a toothbrush to increase the effectiveness of tooth brushing. Toothbrushes are available with different bristle textures, sizes and forms. Most dentists recommend using a toothbrush labelled "soft", since hard bristled toothbrushes can damage tooth enamel and irritate the gums.The predecessor of the toothbrush, the chew stick, first appeared in Egypt and Babylonia, and the earliest bristle toothbrush originate in China. Toothbrushes were introduced to Europe through merchants and travelers in East Asia by the 17th century. DuPont introduced the nylon toothbrush in the 1930s.