Teeth blackening is usually done during puberty. It was primarily done to preserve the teeth into old age, as it prevents tooth decay similar to the mechanism of modern dental sealants. It was seen as a sign of maturity, beauty, and civilization. A common belief is that blackened teeth differentiated humans from animals. Teeth blackening is often done in conjunction with traditions of tooth sharpening and evulsion, as well as other body modification customs like tattoos. Teeth blackening and filing were regarded with fascination and disapproval by early European explorers and colonists. The practice survives in some isolated ethnic groups in Southeast Asia and Oceania but has mostly disappeared after the introduction of Western beauty standards during the colonial era.