Selection of contra-angle handpieces
How large must the selection of straight and contra-angle handpieces be in a dental practice?
Air or electric motors are used as drive units for straight and contra-angle handpieces in the dental practice. The gear ratio of the handpiece means that different instrument speeds can result from the drive speed. Handpieces with 1:1 ratios (i.e. producing the same speed as the drive) or speed-reducing ratios (i.e. producing a lower speed at the rotary instrument than from the drive) are commonly used.
With electric motors, preparation can also be carried out with a 1:5 speed-increasing ratio. This allows a speed of up to 200,000 rpm with a higher torque than can be achieved with a turbine.