title: Efficacy of anti-retraction devices in preventing bacterial contamination of dental unit water lines.
abstract: OBJECTIVE
  In this study we examine the efficacy of anti-retraction devices in preventing microbial contamination of dental unit water lines (DUWLs).
  
  
  METHODS
  The study was performed on 54 randomly selected DUs in use at private and public institutions for over six months. The selected DUs were all currently commercially available. To evaluate the efficiency of anti-retraction devices, two different methods were employed, mechanical and microbiological. The ADA/ANSI specification #47 (corresponding to a water retraction of less than 40.3 microl) was used for the evaluation of the retraction determined using the mechanical method; the presence/absence of test microorganisms in DUWLs upstream the turbine after the test was used for evaluating the microbiological assay.
  
  
  RESULTS
  Both evaluation methods indicated correct amounts of retraction and prevention of DUWL contamination occurred in only two cases (3.7%). Correct retraction was noted in six other dental units (DUs), but their DUWLs became contaminated during testing. Six other produced the opposite results-improper retraction, yet no contamination. The remaining 40 DUs (74.0%) failed both evaluations.
  
  
  CONCLUSIONS
  The results showed that the overwhelming majority of the anti-retraction devices did not prevent retraction when the turbine stopped running, leading to a contamination of the water lines, and to a consequent possible cross-contamination of the patients.
authors.affiliation: Dipartimento di Scienze di Sanità Pubblica (Sezione di Microbiologia), Università di Roma La Sapienza, Piazzale A. Moro 5, Rome, Italy. francesca.berlutti@uniroma1.it
authors.forename: Francesca
authors.initials: F
authors.lastname: Berlutti
authors.forename: Luca
authors.initials: L
authors.lastname: Testarelli
authors.forename: Francesco
authors.initials: F
authors.lastname: Vaia
authors.forename: Massimo
authors.initials: M
authors.lastname: De Luca
authors.forename: Giovanni
authors.initials: G
authors.lastname: Dolci
mesh_terms: D001407:Bacillus / Q000302:isolation & purification; D015169:Colony Count, Microbial; D003748:Dental Equipment / Q000382:microbiology*; D003754:Dental High-Speed Equipment; D004203:Disinfection / Q000379:methods; D004866:Equipment Contamination / Q000517:prevention & control; D004867:Equipment Design; D006801:Humans; D019552:Infection Control, Dental / Q000295:instrumentation / Q000379:methods; D008422:Materials Testing; D013171:Spores, Bacterial / Q000302:isolation & purification; D013499:Surface Properties; D014871:Water Microbiology; D018508:Water Purification / Q000295:instrumentation / Q000379:methods