Evaluation of a protocol for reducing the microbial contamination of dental unit water.

Biofilm on dental unit waterlines can spread microbial contamination in the water. The aim of this study was to investigate microbial contamination of water from supplies and dental units before and after the implementation of a protocol for microbial quality improvement and maintenance of dental unit water. The microbial load was evaluated in water from 27 taps and dental units (reservoirs, air-water syringes and highspeed outputs without handpieces) using the PetrifilmT system (total aerobic bacteria and fungi) and conventional culture media (enterobacteria and Legionella spp.). The bacterial load in water samples from taps and reservoirs was within the parameter established by Brazilian legislation (<500CFU/mL); but the bacterial load in samples from air-water syringes and high-speed outputs without handpieces was not. The implementation of the protocol for the maintenance of microbial quality in dental unit water reduced bacterial load in highspeed outputs without handpieces (p=0.004). Enterobacteria and Legionella spp. were not isolated from any of the water samples from taps and dental units. Sociedad Argentina de Investigación Odontológica.