Dental drill

When a tooth develops a cavity, the decayed tissue must be removed. The earliest devices for doing this were picks and enamel scissors. Later, two-edged cutting instruments were designed that were twirled in both directions between the fingers. The father of modern dentistry, Frenchman Pierre Fauchard (1678-1761), described an improved drill in 1728. Its rotary (turning around a central point) movement was powered by catgut twisted around a cylinder, or by jewelers' bowstrings. A hand-cranked dental drill bit was patented by John Lewis in 1838. George Washington's dentist, John Greenwood (1760-1819), invented the first known "dental foot engine" in 1790. Greenwood adapted his mother's foot-treadle (pedal) spinning wheel to rotate a drill. Greenwood's dentist son continued to use the drill, but the idea went no further.

Modern dental drills are turbine-powered and rotate at speeds of 300,000 to 400,000 revolutions per minute.
Modern dental drills are turbine-powered and rotate at speeds of 300,000 to 400,000 revolutions per minute.

Early Drill Designs

Scottish inventor James Nasmyth used a coiled wire spring to drive a drill in 1829. Charles Merry of St. Louis, Missouri, adapted Nasmyth's drill by adding a flexible cable to it in 1858. The first motor-driven drill appeared in 1864, the design of Englishman George F. Harrington. This "motor drill" was a hand-held device powered by the spring action of a clock movement. In 1868 American George F. Green introduced a pneumatic (air-driven) drill powered by a pedal bellows. Fellow American James B. Morrison patented a pedal bur drill in 1871. A further improvement of the Nasmyth-Merry design, the bur drill featured a flexible arm with a handpiece to hold the drill, a foot treadle, and pulleys. Each of these developments increased the speed at which the drill operated.

In 1874, six years after he made his original contribution to drills, Green added electricity to the dental drill. Green's drill was powered by electromagnetic motors and worked well, but it was also heavy and expensive. Plug-in electric drills became available in 1908. By that time, most dental offices had electricity.

The Modern Dental Drill

Once efficient, mechanically-driven drills became widely available, teeth could be properly and accurately prepared for well-fitting crowns (an artificial substitute for the part of the tooth projecting beyond the gum line) and fillings. American teeth blossomed with the gold of inlays (a filling for a tooth made from a mold) and crowns. Modern dental drills are turbine-powered and rotate at speeds of 300,000 to 400,000 revolutions per minute. Drills generate a large amount of heat but are less irritating to the patient because the cutting action is smoother.

[See also Dental fillings, crown, and bridge ]

User Contributions:

1
lloyd cook
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After reading the above data with interest, I was wondering, with the drill turning at so many revolutions per minute (300,000 to 400,000) wouldn't the heat created from the high friction tend to burn rather than "drill" - hence do some damage?
2
manoj
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there is very less friction as the bearing used is "air bearing" and not the ball bearings.
3
KkZ
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If the drill is capable to work above 400,000 rpm, will this make its work better?
4
NIGEL ALLEN
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As the inventor of the air bearing high speed dental drill in the late 1960 and later founding Westwind Air Bearings company I can answer shortly your readers comments. It is true that very high speeds create great friction at the cuttting bur tip. To use such high speed it was also necessarry to make improved water cooling directed at the bur tip consisting of drops of water blown by air as otherwise the centifugal force of rotation prevents the water reaching the cutting area. In addition my work involved getting manufacturters to make better accurate cutting burs, held securely in a metal chuck in the drill shaft. This development took many months to develope as was the selection of the correct materials for the correct function of the air bearing parts. Consider a shaft running at in excess of 500,000 rpm being stalled to a stop by a heavy handed dentist. The friction caused would seize most bearing surfaces together in an instant. I finally found a combination of shaft and bearing material that would suffer repeated stalls without seizure and it was this aspect of this invention that made it a success. However it is a very long story where we do not have rooome here to cover. Hope this answers your queries. Regards Nigel Allen LDS.RCS(Eng)
5
Kit
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I thought Australian John Walsh developed the first high-speed dental handpiece around 1950-1960 in NZ? Nigel Allen, could you please explain the difference of what he developed to what you invented to someone who is a novice in the world of dentistry? My ignorance isn't meant to offend you, I just am unsure who did what?
6
daljeet
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This article is mild blowing..give me alot of information about dentistry history...
7
Linda Mundell
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I have acquired a treadle dental drill and would like to find pictures of the inventions listed in this article, so I can date my piece. It sounds like a Greenwood design, possibly the dentist son, Greenwood.

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