Cleaning your teeth may be the oldest human habit, according to a palaeontologist whose experiments suggest early humans used grass stalks as tooth picks.

This week's New Scientist reports the findings by palaeontologist Leslea Hlusko of the University of Illinois at Urbana-Champaign.

Curved grooves between 1.5 to 2.6 millimetres wide on the roots of teeth from ancient hominids suggest they were indeed concerned about dental hygiene and used implements to pick their teeth. But critics of the hypothesis have pointed out that modern humans who regularly use toothpicks do not have similar grooves.

In a published in Current Anthropology, Hlusko argues that grass stalks were used as toothpicks by early humans and made the distinctive dental grooves.

To prove the point, she spent eight hours grinding a piece of grass along a tooth taken from a baboon, and replicated the experiment for thee hours on a modern human tooth. In both cases, the grooves astonishingly replicated the marks found on early hominid teeth found by electron microscopes.

"Unlike wood, grass contains large numbers of hard, abrasive silica particles. This may explain the grooves seen on ancient teeth," New Scientist says. "In both, the grass left marks almost identical to those seen in scanning electron microscopic images of early hominid teeth."

Dental grooves have been found on fossil teeth dating back 1.8 million years.

The source of the given news and copyrights belong to the ABC Online News

Back