How dental drills work

Powered by electric or air-driven motors, modern dental drills have come a long way since the early days of medieval dentistry. As well as a motor, the other main components of today’s dental drills are an ergonomic handpiece, gears and a tungsten drill bit, also known as a bur.

Located inside the drill’s handpiece is a series of drive shafts and gears that transmit rotary motion from the power supply to the tungsten drill bit at the head end. Electrically motorised drills can rotate at about 30,000rpm. For a turbine-powered drill, a compressor converts pressurised air into mechanical energy that rotates the bur at over 300,000rpm.

This generates a huge amount of heat, so high-speed devices are also connected to a cooling water supply. New technologies in development – including laser and air-abrasion drills – are hoping to improve the experience of going to the dentist by providing drills that remove decay without generating the heat, noise and vibrations associated with their predecessors.

The laser drill achieves this by combining the high-speed pulsed light from a laser with an atomised spray of water droplets to generate hydrokinetic energy. Air-abrasion drills, meanwhile, work like a mini sandblaster that fires a stream of abrasive powder (such as silica or aluminium oxide) at the tooth to blast the decay away.