A study to determine the qualitative and quantitative contamination of dental unit reservoir water found widespread contamination of potentially pathogenic bacteria in the water (Future Microbiology, May 2013, Vol. 8:5, pp. 681-689).
The study included water samples from 107 unit reservoirs, which Polish researchers analyzed for aerobic and facultative anaerobic bacteria contamination and the risk these pathogens may pose to dental staff and patients. They used conventional microbiological methods and divided bacteria into three groups according to pathogenic mechanisms.
The study found widespread contamination with an average concentration of isolated bacteria of 1.1 Ă— 105 colony-forming units per milliliter (CFU/mL), with Ralstonia pickettii as the prevailing species (49.33%). The total potentially pathogenic bacteria were 54.54% of all the isolated bacteria.
Bacteria causing infectious and invasive diseases constituted more than one-half of this group, while allergizing and immunotoxic bacteria occurred in smaller quantities, the study authors noted.
They concluded that the presence of more than 50% potentially pathogenic microorganisms among the isolated bacteria and the very high concentrations recommends the daily use of effective methods to reduce dental unit water contamination and health risk.
