Modern dental drills can rotate at up to 800,000 rpm, and generally use hard metal alloy bits (actually small rotary files) known as 'burs'. Dental burs come in a great variety of shapes designed for specific applications. They are often made of steel with a tungsten carbide coating, or of tungsten carbide entirely. The bur may also have a diamond coating.
Dental drills, which have a distinctive, shrill sound, are often a prominent factor in many people's fear of dentistry (dentophobia).
Archeological researches in the area of the Indus Valley Civilization Mergarh, Pakistan / India, resulted in the finding of eleven human teeth that had been treated with flintstone tools. Cavities of 3.5 mm depth with concentric groovings indicate use of a drill tool. The age of the teeth has been estimated at 9000 years. In later times, mechanical hand drills were used. Like most hand drills, they were quite slow, with speeds of up to 15 rpm. In 1864, British dentist George Fellows Harrington invented a clockwork dental drill named Erado. The device was much faster than earlier drills, but also very noisy. In 1868, American dentist George F. Green came up with a pneumatic dental drill powered with pedal-operated bellows. James B. Morrison devised a pedal-powered burr drill in 1871.
The first electric dental drill was patented in 1875 by Dr. Green, a development that revolutionized dentistry. By 1914, electric dental drills could reach speeds of up to 3000 rpm. A second wave of rapid development occurred in the 1950s and 60s, including the development of the air turbine drill.
The modern incarnation of the dental drill is the air turbine handpiece, developed by John Patrick Walsh (later knighted) and members of the staff of the Dominion Physical Laboratory (DPL) Wellington , New Zealand. The first application for a provisional patent for the handpiece was granted in October 1949. This handpiece was driven by compressed air. The final model is held by the Commonwealth Inventions development Board in Canada. The New Zealand patent number is No/104611. The patent was granted in November to John Patrick Walsh who conceived the idea of the contra angle air-turbine handpiece after he had used a small commercial-type air grinder as a straight handpiece. Dr. John Borden developed it in America and it was first commercially manufactured and distributed by the DENTSPLY Company as the Borden Airotor in 1957.
Current iterations can operate at up to 800,000 rpm, however, most common is a 400,000 rpm "high speed" handpiece for precision work complimented with a "low speed" handpiece operating at a speed that is dictated by a micromotor which creates the momentum (max up to 40,000 rpm) for applications requiring higher torque than a high-speed handpiece can deliver.
Much has been done by Roger C. Field with and other patents to attempt to interest the industry in his proposals to minimize the possibility of cross-contamination, if handpieces are not sterilized between patients.
Starting in the 1990s, a number of alternatives to conventional rotary dental drills have been developed. These include laser ablation systems and air abrasion devices (essentially miniature sand blasters).