history of dental highspeed handpiece

human beings always had struggled with tooth decay and always had a thought how can get rid of it.before bronze age, people usually suffer from tooth ache until such a time that the decayed tooth become mobile and suddenly or intentionally be removed.  until such a time in bronze age that the Indus Valley Civilization has yielded evidence of dentistry being practiced as far back as 7000 BC. The Indus Valley Civilization (IVC) was a Bronze Age civilization (6000–1300 BCE; mature period 2600–1600 BCE) mainly in the northwestern regions of the South Asia, extending from what today is northeast Afghanistan to Pakistan and northwest India.  This earliest form of dentistry involved curing tooth related disorders with bow drills operated which is an ancient form of drilling tool. It commonly was used to make friction fire, and in this function it also was called a fire drill. However, the same principle also was used widely in drilling for purposes of woodworking and dentistry, perhaps, by skilled bead craftsmen. The reconstruction of this ancient form of dentistry showed that the methods used were reliable and effective. 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 (mechanisms utilizing a complex series of gears)  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 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 (or air rotor) hand piece, developed by John Patrick Walsh (later knighted) and members of the staff of the Dominion Physical Laboratory (DPL) Wellington, New Zealand. The first official 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. Borden Airotors soon were also manufactured by different other companies like KaVo Dental, which built their first one in 1959.

Current iterations can operate at up to 800,000 rpm, however, most common is a 400,000 rpm "high speed" hand piece for precision work complemented with a "low speed" handpiece operating at a speed that is dictated by a micro motor which creates the momentum (max up to 40,000 rpm) for applications requiring higher torque than a high-speed hand piece can deliver.