5 Types of Dental Burs & When To Use Them » Diatech ...
2008-1-1 · The start of the modern turbine era may be 1941, when a patent claimed 25 000 rpm (417 /s) for a design using compressed air at 45 psi (310 kPa). 42 The turbine rotor was unusual: a cylinder with a circular arrangement of holes through which air jets from two nozzles were directed. In addition, ball bearings were to be used (as opposed to the sleeve bearings of earlier …
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