Dental chairs contain an intricate network of interconnected narrow-bore flexible plastic waterlines that provide water to irrigate tooth surfaces and open wounds during dental procedures .

This water is also used to provide cooling to dental instruments during use including turbine and conventional hand-pieces and ultrasonic scalers, as heat generated during instrument use can be injurious to teeth and gums. Water supplied to dental chairs can be provided directly from a mains supply or from bottles on the dental chair which are refilled as necessary.

Many studies have shown that dental chair output water is frequently heavily contaminated with microorganisms. This contamination results from the growth and development of microbial biofilms on the internal surfaces of dental waterlines.

These biofilms are formed mainly by microorganisms arriving in low numbers in supply water, such as mains or bottle water, which then adhere to the internal surface of the waterlines and form a biofilm.

Planktonic microbes, seeded from the biofilm and by-products, including bacterial endotoxins are aerosolised by instruments such as ultrasonic scalers and hand-pieces, thus exposing patients and staff to harmful microorganisms, biofilm fragments and bacterial endotoxins.