The plain wooden toothpick is among the simplest of all manufactured objects and is considered the oldest instrument for dental cleaning, one that spans more than just human species.
Several higher primates use similar items to rub or pick their teeth, and growing archaeological evidence from throughout Europe suggests Neanderthals also had a habit of scraping food out of their mouths. We know that because it's left quite the impression on their molars.
A newly analyzed tooth, discovered in a Polish cave in 2010, has now been found with a spindle-like groove on the side, indicating the in-and-out motion of a toothpick.
The dental measurements of the upper premolar and radiocarbon dating of the area all suggest it once belonged to a male Neanderthal in his 30s who was cleaning his teeth in this manner as far back as 46,000 years ago.
"It appears that the owner of the tooth used oral hygiene. Probably between the last two teeth there were food residues that had to be removed," explains archaeologist Wioletta Nowaczewska from the University of Wroclaw in an article for Science in Poland.
"We don't know what he made a toothpick from - a piece of a twig, a piece of bone or fish bone. It had to be a fairly stiff, cylindrical object, which the individual used often enough to leave a clear trace."
Above: a) The radial wear pattern on the inside of the premolar; b) A vertical toothpick groove visible under the wear facet, to the right.
A handful of other teeth have been found in the Stajnia Cave near Kraków, and these are also thought to belong to Neanderthals. Some of them even show similar attempts at prehistoric dental hygiene, although their deterioration makes them more difficult to study.
The remarkable condition of this newly analysed molar has now allowed scientists to carry out 2D and 3D analysis of its enamel, which is generally thinner in Neanderthals compared to Homo sapiens.
Further mitochondrial DNA analysis has confirmed this tooth likely belonged to a Neanderthal, and according to the authors, the tooth's major groove was most probably caused by mechanical abrasion.
The location, shape, orientation, and occurrence of this scratch all match other signs of Neanderthals fussing with their teeth elsewhere in Europe.
In 2017, archaeologists announced the discovery of a unique Neanderthal tooth, found in present-day Croatia, which showed remnants of picking and chiseling from 130,000 years ago - possibly as a way to relieve pain.
Other materials Neanderthals might have used to clean their teeth include bone, sinew, and grass, although these have yet to be confirmed in the archaeological record.
According to the famous engineer Henry Petroski, who wrote an entire book on the toothpick, this humble instrument is one of the most convenient and ready tools in human possession, requiring no parts to assemble, no maintenance, and no instructions to use - or at least, it shouldn't.
In the Hitchhiker's Guide to the Galaxy, the very words that finally push the scientist Wonko into social hermitude are directions for toothpicking, which is believed to be the oldest human habit.
As Wonko remarked, "any civilization that had so far lost its head as to need to include a set of detailed instructions for use in a package of toothpicks, was no longer a civilization in which I could live and stay sane."
Even Neanderthals, it would seem, who are stereotypically assumed to be primitive brutes, had enough common sense and intuition to use the toothpick - without much direction at all.
The study was published in the Journal of Human Evolution.