Alfredo Coppa and friends have a cool short article in Nature detailing evidence for early tooth drilling in Pakistan:
Prehistoric evidence for the drilling of human teeth in vivo has so far been limited to isolated cases from less than six millennia ago. Here we describe eleven drilled molar crowns from nine adults discovered in a Neolithic graveyard in Pakistan that dates from 7,500-9,000 years ago. These findings provide evidence for a long tradition of a type of proto-dentistry in an early farming culture.
The site of Mehrgarh in Baluchistan lies along the principal route connecting Afghanistan to the Indus valley. After intermittent occupations by hunter-gatherers, Mehrgarh's subsistence economy shifted to the cultivation of barley and wheat, cotton domestication and cattle breeding. Diachronic archaeological evidence records an increasingly rich cultural life, with technological sophistication based on diverse raw materials. Excavation of the Neolithic cemetery known as MR3 yielded more than 300 graves created over a 1,500-year time span.
They found 9 individuals with a total of 11 drilled teeth, all first or second molars. The fact that they are all back teeth tends to rule out a cosmetic function, and several of the drill holes have decay associated with them, so they speculate that the purpose may have been "palliative". Of course, there is this:
The perforations exposed sensitive tooth structure, so some type of filling may have been placed in the cavity; however, no evidence survives to confirm this.
They replicate the procedure using period materials:
At Neolithic Mehrgarh, flint drill heads occur in the lithic assemblages associated with beads of bone, steatite, shell, calcite, turquoise, lapis lazuli and carnelian. Using models of these drill tips, we reconstructed a method for drilling based on the ethnographic literature and found that a bow-drill tipped with a flint head required less than one minute to produce similar holes in human enamel.
Is that cool or what?