title: The presence of Pseudomonas aeruginosa in the dental unit waterline systems of teaching clinics.
abstract: OBJECTIVE
  The objective of this study was to evaluate the extent of Pseudomonas aeruginosa contamination of Dental Unit Water (DUW) at a Dental Teaching Center in Jordan.
  
  
  METHODS
  Water samples were collected from 30 dental units, 10 from each of three teaching clinics, namely conservative dentistry, periodontology, and prosthodontics. Samples were collected from the outlet of the air/water syringe, high-speed handpiece and water cup filler, at the beginning of the working day (before use), after 2 min flushing, and at midday.
  
  
  RESULTS
  P. aeruginosa was detected in 86.7% (26/30) of the dental units at the beginning of the working day, and in 73.3% (22/30) after 2 min of flushing and at midday. Conservative dentistry units had the highest counts, followed by periodontology and prosthodontics (P<0.05). Overall, the highest counts (log10 count CFU ml-1) were at the beginning of the working day (1.38+/-1.05), and the lowest counts after flushing for 2 min (1.10+/-1.03), and higher numbers were seen again at midday (1.15+/-1.04) (P<0.05).
  
  
  CONCLUSIONS
  86.7% of the dental units were contaminated with P. aeruginosa, the conservative dentistry units had the highest amount of contamination. Flushing the DUW for 2 min significantly reduced the counts of P. aeruginosa.
authors.affiliation: Department of Restorative Dentistry, Faculty of Dentistry, Jordan University of Science and Technology, Irbid, Jordan. hiyasat@just.edu.jo
authors.forename: A S
authors.initials: AS
authors.lastname: Al-Hiyasat
authors.forename: S Y
authors.initials: SY
authors.lastname: Ma'ayeh
authors.forename: M Y
authors.initials: MY
authors.lastname: Hindiyeh
authors.forename: Y S
authors.initials: YS
authors.lastname: Khader
mesh_terms: D015169:Colony Count, Microbial; D003740:Dental Clinics; D003748:Dental Equipment / Q000382:microbiology*; D003754:Dental High-Speed Equipment / Q000382:microbiology; D003762:Dental Instruments / Q000382:microbiology; D003814:Dentistry, Operative / Q000295:instrumentation; D004866:Equipment Contamination; D005374:Filtration / Q000295:instrumentation; D006801:Humans; D010377:Pediatric Dentistry / Q000295:instrumentation; D010517:Periodontics / Q000295:instrumentation; D011476:Prosthodontics / Q000295:instrumentation; D011550:Pseudomonas aeruginosa / Q000254:growth & development* / Q000302:isolation & purification; D012575:Schools, Dental; D013997:Time Factors; D014871:Water Microbiology