Known. People at Mehrgarh drilled holes in the teeth of living people.
Mehrgarh is on the Kachi Plain, near the Bolan Pass, in Balochistan, Pakistan. The first village there dates to between 7000 and 5500 BC. People grew barley and wheat and kept sheep, goats, and cattle. Researchers found 11 drilled teeth from nine people. The edges of the holes were worn smooth. That shows the people kept chewing with these teeth after the holes were made. It is the earliest sign found of teeth being drilled in a living person. Flint drill tips were found at the site. In tests, drills like these made a similar hole in less than a minute.
People may have first learned to drill by making beads, then used it on teeth. That is only a guess.
https://www.ancient-origins.net/ancient-places-asia/mehrgarh-0012615