Dental drill
The handpiece itself consists of internal mechanical components that 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 the overall success of the procedure.
The turbine is powered by compressed air between 35 and 61 pounds per square inch (~2,4 to 4,2 bar),[1][2] which passes up the centre of the instrument and rotates a Pelton wheel in the head of the handpiece.
The centre of the windmill (chuck) is surrounded by bearing housing, which holds a friction-grip burr firmly & centrally within the instrument.
Inside the bearing housing are small, lubricated ball-bearings (stainless steel or ceramic), which allow the shank of the burr to rotate smoothly along a central axis with minimal friction.
Older handpieces utilized a system of halogen lamps and fiber-optic rods, but this method has several drawbacks: halogen bulbs decay over time and are costly to repair, and fiber-optic rods fracture readily if dropped and disintegrate through repeated autoclaving cycles.
Generally used for operative procedures such as the removal of dental caries or for polishing enamel or restorative materials.
A straight, slow-speed handpiece is generally indicated for the extra oral adjustment and polishing of acrylic and metal.
[7][8] The United States Food and Drug Administration classes burrs as "single-use devices",[9] although they can be sterilised with proper procedures.
[10] This earliest form of dentistry involved curing tooth-related disorders with bow drills operated, perhaps, by skilled bead craftsmen.
In 1864, British dentist George Fellows Harrington invented a clockwork dental drill named Erado.
In 1868, American dentist George F. Green came up with a pneumatic dental drill powered by pedal-operated bellows.
The contra-angle was invented by John Patrick Walsh (later knighted) and members of the staff of the Dominion Physical Laboratory (DPL) Wellington, New Zealand.
These include dental laser systems,[17] air abrasion devices (devices that combine small abrasive particles with pressurized air, essentially miniature sand blasters),[18][19] and dental treatments with ozone or silver diammine fluoride (SDF).
