The `dental foot engine' was invented by the dentist John Greenwood, who looked after George Washington's teeth. In 1790, Greenwood adapted his mothers spinning wheel so that it would rotate a drill. The only person not to ignore Greenwood's device was his son, who was also a dentist.
The primitive forms of dental drills were joinery drills which were operated by turning a handle fixed at one side. A leap in dental technology came from the work of the Scot, James Nasmyth. Nasmyth devised a way of making rotary power turn corners, a coiled steel spiral within a sleeve enabled him to do this.
Many more people developed ideas for the dental drill. Among them was Charles Merry of America, who in 1858 patented a hand-operated drill with a flexible cable. Another was Englishman George Fellows Harrington who invented the first motor-driven dental drill in 1864. It was a clockwork hand-held device with a drill attached to it.
Modern dental drills operate at high speed, the head is rotated by purified water which also acts as a coolant at the drill tip.
