Tooth whitening is a kind of brightening which helps teeth recover their original color. It should not be understood as whitening, experts said Friday.
Tooth whitening does not mean that the color of teeth will change. It is aimed at helping darker teeth recover its original color, they said.
To become a “tooth beauty,” one should have teeth with the proper size and form, and the teeth should maintain a good posture, they said.
According to historical records, black teeth were a prerequisite to becoming a beauty in Japan during the Tokugawa Makbu period (1603-1867).
Japanese regarded black teeth as a symbol of eternal harmony between husband and wife and constancy, the records say.
Before marriage, a bride would hold a ceremony to dye her teeth black, they say.
Such peculiar Japanese customs were conveyed to the West by Matthew C. Perry, a U.S. naval officer who headed an expedition that forced Japan in 1853-54 to enter into trade and diplomatic relations with the West after more than two centuries of isolation, the records say.