Dental handpiece are divided into dental high-speed handpiece and dental low-speed handpiece. Dental high-speed handpiece, also known as high-speed pneumatic turbine handpiece, dental drill handpiece and so on, is a commonly used medical device in stomatology. Its working principle is driven by compressed air, driving the wind wheel to rotate at high speed, so as to drive the dental needle to complete the drilling and grinding of teeth. The rotating speed of high-speed handpiece is more than 300000 revolutions per minute, which is mainly used for treatment and repair (such as drilling and chipping). Low speed handpiece are divided into straight machine and bending machine. Straight machine is used for grinding and polishing. It is treated outside the mouth. Bending machine is treated inside the mouth.