High-speed handpiece
- Can cut at speeds of up to 180,000 rpm
- Classified as air turbine or speed-increasing
- Air turbine handpieces commonly referred to as high-speeds
- Have a chuck or collet for holding a cutter called a burr
- Used in clinical context for various dental procedures

Mechanisms
- Powered by compressed air between 35 and 61 pounds per square inch
- Turbine rotates a Pelton wheel in the head of the handpiece
- Bearing housing holds the burr firmly and centrally within the instrument
- Small ball bearings allow the burr to rotate smoothly along a central axis
- Failure to run centrally can cause clinical defects and decreased control

Cooling
- High-speed friction generates heat within the burr
- High-speed handpieces have an excellent water-cooling system
- Standard cooling water flow rate is 50 ml/min
- Cooling water is provided through 3 to 5 spray hole jets
- Effective cooling is essential to prevent overheating

Illumination
- Modern handpieces have a light in close proximity to the burr
- Light is directed at the cutting surface to assist with vision
- Older handpieces used halogen lamps and fiber-optic rods
- Halogen bulbs decay over time and are costly to repair
- LED technologies are now used for longer operating life and better light production

Speed-increasing handpiece
- Electric motors cannot turn as fast as air turbines
- Gears are needed to increase the speed of an electric motor
- Also known as micromotor
- Power is provided by the micromotor and internal gearings
- Allows cutting speeds over 180,000 rpm

Evolution of Dental Drills:
- Ancient dentistry involved the use of bow drills operated by skilled craftsmen.
- Mechanical hand drills were introduced in later times, but they were slow.
- In 1864, British dentist George Fellows Harrington invented the clockwork dental drill named Erado, which was faster but noisy.
- In 1868, American dentist George F. Green developed a pedal-operated pneumatic dental drill.
- James B. Morrison created a pedal-powered burr drill in 1871.
- The first electric dental drill was patented in 1875 by George F. Green, revolutionizing dentistry.
- By 1914, electric dental drills could reach speeds of up to 3,000 rpm.
- In the 1950s and 60s, the development of the air turbine drill brought further advancements.
- The modern incarnation of the dental drill is the air turbine contra-angle handpiece, allowing access to less accessible areas of the mouth.
- Current iterations can operate at speeds up to 800,000 rpm.

Alternatives to Conventional Dental Drills:
- Starting in the 1990s, alternatives to rotary dental drills have been developed.
- Dental laser systems have been introduced as an alternative tool for dental work.
- Air abrasion devices combine small abrasive particles with pressurised air for precise dental treatments.
- Ozone and silver diamine fluoride (SDF) have also been used as alternative dental treatments.
- These alternatives offer different benefits and applications in restorative dentistry.

Dental drill (Wikipedia)

A dental drill or dental handpiece is a hand-held, mechanical instrument used to perform a variety of common dental procedures, including removing decay, polishing fillings, performing cosmetic dentistry, and altering prostheses. The handpiece itself consists of internal mechanical components which initiate a rotational force and provide power to the cutting instrument, usually a dental burr. The type of apparatus used clinically will vary depending on the required function dictated by the dental procedure. It is common for a light source and cooling water-spray system to also be incorporated into certain handpieces; this improves visibility, accuracy and overall success of the procedure. The burrs are usually made of tungsten carbide or diamond.