The Parts of a Dental High-Speed Handpiece

The dental high-speed handpiece ("drill") is an essential component of every dentist's toolkit. This device is a power-driven, rotary instrument capable of speeds of 400,000 RPM and higher. Uses include removing decay (cavities) from teeth and preparing teeth for fillings and other restorations.

In the dental office and the dental laboratory, the high-speed handpiece (along with the slow speed handpiece) is a primary tool for cutting and polishing dental trays, models and appliances such as dentures.

Operation

• The high-speed handpiece is activated by pressing a rheostat pedal located on the floor. This foot pedal also controls the speed of the handpiece, similar to the accelerator on a car.

  Most models in use today employ compressed air to drive the turbines inside. The movement of the turbines creates the rotary action at the end of the handpiece. Drill bits, also known as burs, discs or stones depending on their function, are attached to the end of the handpiece and perform the cutting action on the tooth or other material.

Head

• The head, or working end, of the high-speed handpiece is where the burs and other cutting or polishing attachments are connected. Options for the head include standard size as well as pediatric size for small mouths.

  High-speed cutting generates significant friction heat, which can damage the nerve, so the head often features a built-in air, water or air-water spray that acts as an on-demand coolant. Many high-speed handpiece models also include a fiber-optic light source to help the dentist view the treatment area more easily.

Chuck

• The chuck is the part of the head that holds the burs and other high-speed handpiece attachments. There is a small hole in the chuck into which the attachments are inserted and removed from the handpiece.

  With some handpiece models, a bur tool or wrench is used to insert or remove the attachments. Other models have a built-in button or lever on the back of the head, eliminating the need for a separate tool.

Shank

• The shank, or handle, is located between the head and the connection end of the high-speed handpiece. The shank is often contra-angled (at an angle with) the head. This contra-angle provides improved accessibility and visibility during many types of operative dental procedures.

  In a right-angle handpiece, the head is at a 90 degree angle to the shank and is not contra-angled. The most common handpiece of this type is the prophy angle, used with an attached rubber cup to polish teeth.

Connection End

• The connection end of the high speed handpiece is attached to the shank on one end and to flexible hoses and cords on the other. These hoses and cords enclose the wires from the power source. They also transport water to the handpiece and contain the fiberoptic cords for the light source.

  Proper management of these hoses and cords can prevent entanglement and increase the efficiency of dental procedures. The forward and reverse controls for the handpiece are often located on the connection end as well.