Teeth whitening

Why tooth color attracts our attention

A smile makes the teeth immediately visible. Their appearance can contribute to the impression of youth and good health, which has led researchers to consider a role in attraction between partners. Teeth tend to darken with age, so a light shade could contribute to this impression. This is a plausible evolutionary hypothesis, not the demonstration of an innate and universal taste for white.

In 2012, Hendrie and Brewer showed 150 people photographs with altered teeth color and spacing. The yellowed versions were less well evaluated, but teeth whitened beyond the natural shade did not bring any gain in attractiveness. This experiment measures judgments in a given context; it does not make it possible to separate biological heritage from cultural learning on its own.

In Japan, a smile could be black

During the Edo period, Japanese makeup notably combined white face powder, red makeup and black eyebrows and teeth. Ohaguro consisted of deliberately blackening the teeth. The prints and objects presented by the Mizuta museum show this practice within a worked aesthetic whole, with hairstyles, clothing and accessories.

The uses of adornment varied according to age, social status and marital status. It would therefore be misleading to present ohaguro as an identical preference among all Japanese, in all periods. But this example is enough to remind us that a black tooth could be part of a desired appearance, far from the negative meaning that many would give it today.

In Vietnam, a practice attested two millennia ago

A study published in 2026 analyzed three dental samples from the Dong Xa site in northern Vietnam, approximately two thousand years old. The analyses, compared with tests and ethnographic descriptions, support the existence of voluntary blackening using iron salts, probably associated with substances rich in tannins. Here we go beyond the simple observation of dark teeth found in a grave.

Closer to home, a 2006 study describes a darkening associated with beauty and a belief in protection against cavities among Kammu women from Laos and Vietnam. The authors then indicate that the practice persists especially among the elderly. The same aspect can thus lose its aesthetic value in a few generations, without human biology having changed in the meantime.

Different colors don't always say the same thing

It is also necessary to distinguish black coloring applied voluntarily from brown-red tints linked to certain chewing habits. Researchers working on Vietnam rightly highlight this difficulty of interpretation. A colored tooth in an ancient source does not prove that this color was sought for its own sake, and the documented blackening does not support a general preference for yellow teeth.

The arrival of modern treatments at home

In 1989, dentists Van Haywood and Harald Heymann published “Nightguard vital bleaching”, a milestone in modern whitening using trays. The approach contributes to the development of treatments carried out at home with a gel, in a dental setting. Lightening thus becomes compatible with a series of home applications, rather than just carrying out sessions in the office.

Strips, gels and other products intended for the general public then increased the number of ways to promise a clearer smile. Their diversity, however, makes comparisons difficult: the 2018 Cochrane review does not make it possible to designate with certainty one formula or method of application superior to all the others. The history of money laundering is also that of a commercial offer that has become much broader than the evidence allowing it to be decided.