Frequently Asked Questions

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Glossary of Dental Handpiece Terms

By: Steve Aucremann


Air Motor – A slow speed handpiece without internal reduction gears or attachments, usually rotating at speeds near 20,000 rpm.

Attachment – a nose cone or angle that quick disconnects on and off the front of a low speed motor to provide various bur holding options.

Auto Chuck – A mechanism enabling the operator to change a bur without the use of a wrench, by pressing a button or raising a lever.

Autoclave – A steam sterilizer which destroys all living organisms through the medium of heat and pressure. Temperatures are raised to 270-275°F while the pressure is raised to 30 psi.

Bur – A rotary dental instrument, which when placed in a handpiece is used to cut or carve tooth structure. Burs come in a variety of shapes and sizes and can be made of high speed steel, carbide, or diamond coated material.

Canister Turbine – A closed cylinder which houses a rotating turbine assembly inside the head of the handpiece. Designed for easy replacement.

Chemiclave – A sterilizer which uses a chemical to generate chamber pressure instead of steam. The absence of water in the process reduces rust and oxidation of instruments.

Chip Air – Air supplied through the handpiece from the dental unit tubing to the cutting surface to cool the tooth or disperse the water spray, while flushing away residual material resulting from the removal of tooth structure. In a High Speed electric attachment the chip air is also an important source of cooling for the head of the attachment.

Chuck – The part in the handpiece turbine used to hold the bur.

Collet – Another word for the chuck, generally refers to part of the chuck that actually grips the bur.


Connector – Attaches the handpiece to the dental delivery unit that supplies air and water to the handpiece. There are four types of standard U.S. connectors. They include the 2, or 3-Line (also called a Borden) and 4-Line. The 4-Line (also known as a Midwest) is the most popular connector. In a 4-Line connector, the holes are (1) drive air, (2) chip air, (3) water, and (4) exhaust. Sometimes a fifth line or hole is added for a fiber optic bundle. A newer type of connector, 6 Pin, is now available which provides
an electrical connection for a fiber optic light bulb. Hole size and location are indicated by a standardized ISO specification.

Contra Angle
– The front section of a handpiece which changes the desired angle to provide better bur access and visibility to the operator during use.

Coolant – Refers to the water and air spray directed at the bur to cool the tooth when cutting. Doriot handpiece - Often used to refer to the handpiece for a belt drive but it actually refers to any handpiece motor that accepts a standard 3/32 bur shank or an angle or attachment which slides on to the nosecone and has the 3/32 shaft that fits into the chuck.

Doriot or Universal Angle –Any angle that operates on the front of a nose cone that has a protruding shaft designed to fit into the nose cone chuck.

Drive Air – The compressed air used to rotate the turbine or vain motor in a dental handpiece. In the Electric operatory motor the drive air pressure controls the RPM of the motor and provides cooling to the motor.

Electric lab Handpiece – Hand held electric motor that takes 3/32 shank burs used in a lab for trimming and grinding. They operate at maximum speeds from 25k to 50k RPM and are either a brush motor that runs off DC current or a brushless motor which runs off a 3 phase signal.

Electric operatory motor
– These electric powered motors are normally attached to the dental unit in the place of a Highspeed handpiece and can drive a variety of attachments that that achieve different speeds at the bur by a system of gears to step up or step down the speed of the motor. “E” Type Motor – A motor with a standardized male connection (ISO standard) that accepts attachments with the matching female connection.

End Cap – The cap or cover which is removed to install the turbine may also contain the button or lever to actuate the chuck.

Exhaust – The air discharged from a dental handpiece after spinning the turbine. Fiber Optic Handpiece – A handpiece through which a transparent fiber or glass rod optic bundle transmits light to illuminate the area around the bur.

Friction Grip Chuck
– A chuck which holds the bur strictly by friction generated from an internal spring assembly. The bur is simply pushed in and out of the chuck with a special tool using force to overcome friction.

Handpiece – A handheld device which engages rotary instruments for cutting, cleaning or polishing the teeth. A handpiece can be belt-driven, pneumatic (air or gas driven) or electric.

High Speed Handpiece – A handpiece which operates at a speed greater than 50,000 RPM.

Jacobs Chuck – A mechanism which utilizes a wrench to tighten the chuck. This design incorporates slots which create jaws that are compressed onto the bur shank when tightened with the corresponding wrench.

Latch Angle – An attachment that holds a specialized bur which is mechanically retained by the use of a swinging hook that engages a recess in the bur shank.

Low Speed Handpiece (or Slow Speed)
– A handpiece which operates at speeds ranging from 5,000 to 40,000 rpm.


Lubricant or Oil – A liquid applied to moving parts of a handpiece or attachment in order to reduce friction, heat, or wear, or applied to surfaces in close contact to prevent them adhering to one another. May also include a solvent for cleaning.

Nosecone – A straight attachment used with a slow speed motor which holds a lab type bur (3/32” shank) or any standard doriot attachment.

Prophy Angle – An angle that holds a brush or cup containing prophy paste used by a hygienist for cleaning teeth.

Quick-Disconnect – A handpiece attachment or fitting designed to allow easy separation of the handpiece from the supply tubing.

Replacement Cartridge – Another name for a high speed turbine, usually self-contained to allow easy replacement.

Rotary Vane Motor
– A type of low speed motor utilizing small vanes instead of a turbine to trap drive air in a rotor assembly to generate rotation.

– Revolutions Per Minute. A unit of measurement indicating speed.

Straight Handpiece
– Same as a low or slow speed handpiece. Often refers to a handpiece with a nosecone permanently “fixed” to the motor.

– Instead of threads at the rear of a handpiece, the swivel is usually a separate part that threads into the supply tubing and incorporates a quick disconnect. Designed to allow the handpiece to rotate where it attaches to the air supply tubing in order to reduce fatigue on the operators wrist.

– Located in the head of a high speed handpiece, the turbine holds the bur or cutting instrument while rotating from high pressure compressed air. A turbine consists of five components: spindle; chuck; impeller; bearings; and two “O” rings

Our Thanks Joe Pellegrino of Superior Handpiece Service who created the original list.

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