Impact of poor dental health on pneumonia.

saliva into the line due to lack of anti-retraction valves. Even a small amount of Pseudomonas aeruginosa in a municipal water system can contribute to the dental chair unit contamination problem because dental chair units provide a different environment with small bores, narrow lumens and periods of stagnant water. However, if the water is well maintained according to current hygiene guidelines, the prevalence of Pseudomonas aeruginosa in the public water supply is extremely low [6]. As Pseudomonas aeruginosa can be recovered from the oral cavity of ,4% of healthy individuals [7], it is therefore possible that some of these bacteria are aspirated into the dental chair unit waterlines through a defective check valve and are able to colonise in the waterlines. As the suction system hoses and pipe work are frequently wet, they provide an environment that is conducive to the growth and proliferation of biofilms which adhere to the inner surfaces of the lines. This biofilm protects the bacteria both from being washed away by the water flow and from many types of antimicrobial water treatment [8].