The bristle toothbrush, similar to the type used today, was not invented until 1498 in China. The bristles were actually the stiff, coarse hairs taken from the back of a hog's neck and attached to handles made of bone or bamboo. During the 1900s, celluloid gradually replaced bone handles and nylon bristles were introduced by Dupont de Nemours in 1938. The first nylon toothbrush was called Doctor West's Miracle Toothbrush and went on sale on 24 February 1938. Later, Americans were influenced by the disciplined hygiene habits of soldiers from World War II. They became increasingly concerned with the practice of good oral hygiene and quickly adopted the nylon toothbrush.