Doriot linkage
The Doriot linkage (French: tour de Constant Doriot; bras Doriot; English: Doriot's transmission) is a drive cord drive (also referred to as rope transmission , in principle a belt drive ) for the transmission of torque from an electric motor to dental handpieces and contra-angles on dental treatment units .
This historical construction for transmitting the torque is now out of date.
It was invented in 1893 by the Parisian dentist Constant Doriot and from 1957 onwards it was replaced by other types of technical drive ( dental micromotor , dental air turbine ). The Doriot linkage was patented in Philadelphia in 1893 and used by the SS White Dental Manufacturing Company (founded in 1844 by inventor, dentist and science author Samuel Stockton White ; born June 19, 1822 in Hulmeville Pennsylvania; † December 30, 1879 in Paris; for the production of Porcelain Teeth and Dental Instruments; Philadelphia, Pennsylvania; then became the largest dental company in the world).
The Doriot linkage with its drive system was considered the standard in dentistry for many decades . "Drills" (handpieces and contra-angle handpieces) that were driven with Doriot rods typically reached a speed of 6000 / min. The Doriot linkage was gradually replaced by a micromotor and turbine until it was almost completely displaced by 1970.
technology
The Doriot rod, a special rod , consists of three hinged metal arms with swivel joints , over which the drive cord is guided by means of pulleys (cord wheels). The power is transmitted by means of a pulley cord that transmits the revolutions of the electric motor to the drive coupling with the attached dental handpiece with the clamped drill.
The speed was continuously increased through technically complex gear ratios, so that in the 1950s the speed could be increased to 10,000 / min. These higher speeds in turn required the development of special handpieces.
An overdrive was added around 1936, increasing the engine speed from 1200 to 3000 rpm to 6000 rpm, later even to 24,000 rpm. The company Kaltenbach & Voigt (today Kavo Dental ) constructed a joint sliding connection in 1954, which enabled about 60,000 rpm. In 1957 there was also a high-speed Doriot linkage.
The electric motor for driving the Doriot rods was on the patient's left, mostly integrated in a treatment unit with cuspidor and lamp. The Doriot linkage was already hanging in the patient's field of vision during the examination - diagonally to the left in front of and above the patient - and caused anxiety , especially in patients with a phobia of dental treatment . The gallows system was balanced in such a way that the entire weight of the Doriot rods did not pull on the handpiece during the treatment and thus severely impaired the fine motor work of the dentist in the patient's mouth.
prehistory
Before the advent of rotating instruments and the rotating drive (“dentist's drill”), the carious tooth hard substances were removed and the tooth cavity was prepared ( preparation ) for filling therapy using hand instruments (enamel knives, dentine knives, excavators ).
In 1871, Georges Green introduced the battery-powered electric drill in dental treatment. However, it was not until the turn of the century, when battery-operated motors ( submersible batteries ) were replaced by mains-operated motors, that the majority of dentists switched from pedal drills to electric drills . This was accompanied by the triumph of the Doriot linkage, which transferred the higher speeds from the motor to the handpiece with significantly more smoothness. Other improvements to the electric motor for dental care included a starter with built-in resistance and electromagnetic brakes for the motor.
The first primitive dental treatment units existed from 1860. Treatment units in the modern sense, however, did not exist in the USA, which were then world leaders in dental matters, only from 1917. That was the "Ritter Unit" of the Ritter company with an integrated drill, water spray, Air blower, lighting sources and cuspidor. Morison patented the pedal drill in 1870. John Greenwood (1760-1819), the body dentist from George Washington , had already in 1790 the first Tretbohrmaschine (Engl. "Dental foot engine") invented.
The first dental drills were very cumbersome to use, difficult to control, and only had a very slow speed. The drilling out of the cavities for the filling therapy was very tedious.
Until 1894, the pedal drill was the state-of-the-art in the dental treatment of carious defects in conservative dentistry . The pedal drill (then called: "Dental Engine") was patented on February 7, 1871 and introduced in the USA by the New York dentist James Beall Morrison (* December 5, 1829 in East Springfield in Jefferson County / Ohio ; † December 22, 1917 in Kansas City / Missouri) 1872 quickly spread in Europe in a short time, with it speeds of 2000 / min could be achieved. The electric drill prevailed over the pedal drill in 1883 thanks to the construction of a flexible shaft to transmit power to the handpiece. This flexible, flexible shaft in the drill tube allows the dentist to move the handpiece largely freely during treatment. Soon after, the first electric drills for dental treatment appeared. They reached a speed of 1200 to 3000 / min. The power transmission also took place by means of a flexible metal spiral. Also hydraulically operated drilling machines were used (Engl. Water Engine Dental Engine).
The Belgian Emile Huet (1874–1944) had designed a motor for dental treatment as early as 1911 that managed a speed of 10,000 / min, but the handpieces of that time were not designed for such speeds.
Further development
In 1950 the handpiece was further developed into a contra-angle handpiece. The water-powered turbine was invented in 1953 and the dental air turbine in 1957 . In 1965 the companies Kerr and Siemens (later: Siemens dental, then Sirona) manufactured the first dental micromotors. Since the micromotor was attached directly to the handpiece or contra-angle handpiece, the problem of power transmission over a longer distance was completely eliminated. All that was required was a coupling for direct power transmission from the micromotor to the handpiece. The conventional drill with a drill hose or Doriot rods became superfluous in the 1960s.
In 1959, the Siemens subsidiary DCR brought out a device for motor transmission for higher rotational speeds. It was brought onto the market under the name SDSR and among other things dentists called it pig because it looked like it. In Great Britain the device was also called the Mouse .
literature
- Wolfgang Strübig: History of Dentistry. An introduction for students and dentists. Deutscher Zahnärzte Verlag, 1989, ISBN 978-3769110999
- Curt Proskauer, Fritz H. Witt: Picture history of dentistry. DuMont Reiseverlag, 1992, ISBN 978-3770101672
- Malvin E. Ring: History of Dentistry. Könemann, 2000, ISBN 978-3895085994
- Heinz E. Lässig, Rainer A. Müller: Dentistry in art and cultural history. Dumont Book Publishing, 2002, ISBN 978-3832171995
Web links
Individual evidence
- ↑ U.S. Patent Number 111,667 for James B. Morrison's Pedal Drill, accessed February 6, 2011.