In Japan, Ohaguro (お歯黒) is a custom of dyeing one’s teeth black. It was most popular in Japan until the Meiji era. Dyeing is mainly done by married women, though occasionally men do it as well. It was also beneficial, as it prevented tooth decay, in a similar fashion to modern dental sealants.
Because objects that were pitch black, such as glaze-like lacquer, were seen as beautiful, Ohaguro became quite prominent and existed in one form or another for hundreds of years and was seen amongst the population until the end of the Meiji period.
The word “ohaguro” was a Japanese aristocratic term. There is an alternate reading for ohaguro, 鉄漿 (literally ‘iron drink’ “lead”). At the old Imperial palace in Kyoto, it was called fushimizu (五倍子水). Among the civilians, such words as kanetsuke (鉄漿付け), tsukegane (つけがね) and hagurome (歯黒め) were used.
For years Ohaguro was a well practiced fashion but on February 5, 1870, the government banned it and the process gradually became obsolete.
In contemporary times, the only places where ohaguro can be seen is in plays, some festivals, and movies. Some traditional geishas still practice it.
Nowadays, modern Japanese dentists and orthodontist are amused at the reaction of their western counterparts when they introduce them to this strange custom.