When Chinese archaeologists were cleaning up the Mawei Tomb in King Xu, Liao Dynasty, more than 1000 years ago, they found two bone handles very similar to modern toothbrushes, with two rows of holes in the head, which proved that toothbrushes appeared in China at least 600 years earlier than in Europe. The first modern toothbrush was made in 1780. It was officially put into production in France on 1840, and then spread to the United States. At that time, toothbrushes were mainly made of bone handles and natural bristles. Plastic toothbrush handles appeared in the 20th century. In 1930s, people used artificial nylon filaments to make toothbrush bristles instead of natural bristles. With the rapid development of plastic industry, the quality of fine nylon yarn has been improved, and it has been found that the original nylon yarn is very harmful to gums and teeth. Therefore, in the 1940s, soft nylon filaments were used as toothbrush bristles. There are electric toothbrushes abroad now.