Human tooth sharpening is the practice of manually sharpening the teeth, usually the front incisors. Historically, many cultures have practiced this form of body modification. In Bali, teeth were filed down because it was thought that the teeth represented anger, jealousy, and other similarly negative emotions. The teeth were also sharpened as a rite of passage for adolescents.
Teeth filing was also used by Aborigines for spiritual reasons, similar to assorted Vietnamese and Sudanese tribes. In Mayan culture, the teeth were sharpened, and sometimes had designs carved into them, to distinguish those in the upper-classes. Many cultures would sharpen their teeth to imitate animals, such as the Wapare of inter-tropical Africa, who sharpened their teeth to imitate sharks, as well as kicking out some mandibular teeth during puberty.