How it began
Mehrgarh is a Neolithic site in Balochistan province, in present-day Pakistan. In a graveyard there, an international team found eleven drilled molar crowns from people who lived 7,500 to 9,000 years ago. The teeth were drilled with flint drill heads of a kind found at the site. The find was reported in Nature in 2006 by Coppa, Bondioli, Cucina and colleagues. Before this report, the oldest evidence of drilled teeth was at least 1,500 years younger. The flint drill heads at Mehrgarh were found together with beads, which suggests the skill was first developed for bead making and then applied to teeth.
How it works
The holes are 0.5 to 3.5 millimeters deep and were cut into the enamel or the dentine of the biting surface, with one on the side of a lower molar. At least one person shows later carving of the cavity wall. Smoothing around the edges shows the drilling was done on living people who went on chewing with the teeth afterward. Researchers found flint tips surprisingly effective at drilling enamel.
What changed first
All eleven crowns are first or second permanent molars, too far back in the mouth to be seen, which the team took as ruling out decoration. Four teeth show decay associated with the hole, so the drilling may have been meant as treatment or relief in some cases. The exact motive remains unclear.
Where it stands today
The Mehrgarh teeth stand as the oldest known evidence of dentistry on living patients. The original report in Nature described the practice as an early Neolithic tradition of dentistry, and it is routinely cited in the dental literature. The report ran in volume 440 of Nature, and the British Dental Journal summarized it for practitioners the same year.
