Oral pathogens in DUWL's: risk of infection and strategies for their control.

Water lines are an importan! source of potentíal contamination. Every dental unit is equipped with small-bore flexible plastic tubing to bring water to different hand pieces, such as the air/water syringe, the ultrasonic scaler or the high-speed hand piece. Most dental units are connected directly to municipal distribution systems for potable water and chlorinated or not, this water contains diverse microflora that include vlruses, bacteria, yeast, fungi, protozoa, unicellular algae and nematodes. Free-floating (planktonic) microorganisms are vulnerable to environmental stress, biocide activity and microscopic predators. However, once inside the dental unit, such microorganism can settle on the inner turblne surface, lnitiating a chain of events that results in cofonization, microcolony formation and, eventually, biotilm formation [1]