title: Clearance of biofilms from dental unit waterlines through the use of hydroperoxide ion-phase transfer catalysts.
abstract: OBJECTIVE
  The purpose of this research was to demonstrate the effectiveness of hydroperoxide ion-phase transfer catalyst (HPI-PTC) cleaners and disinfectants for maintaining dental unit waterlines free of planktonic organisms.
  
  
  METHODS
  Water samples were taken from 117 sites, which included a variety of dental units and samples from the sink faucets of most operatories. Samples were plated on appropriate bacteriologic media and incubated. The presence or absence of biofilms was confirmed by scanning electron microscopy. Twenty-two of the dental units were retrofitted with independent water systems; the cleaning procedure involved an overnight application of an HPI-PTC cleaner followed by a 2-minute water rinse.
  
  
  RESULTS
  Water from both the air-water syringe and the high-speed handpiece lines from all untreated units contained at least 6 x 10(2) colony-forming units per milliliter of planktonic or free-floating bacteria; the average was 1.4 x 10(5) CFU/mL. An initial 5% solution of HPI-PTC successfully cleared the lines of any apparent biofilm when applied for 3 consecutive days. Thereafter, once weekly use of the cleaner maintained the dental unit water supplies free of significant numbers of planktonic organisms.
  
  
  CONCLUSIONS
  Routine weekly use of an HPI-PTC cleaner controlled dental unit waterline biofilm and reduced, with minimum effort, the microbial contamination level of water used for patient treatment to less than 200 CFU/mL.
authors.affiliation: Endodontics Program, School of Dentistry, University of Louisville, Louisville, Kentucky 40292, USA.
authors.forename: P A
authors.initials: PA
authors.lastname: Shepherd
authors.forename: M A
authors.initials: MA
authors.lastname: Shojaei
authors.forename: P D
authors.initials: PD
authors.lastname: Eleazer
authors.forename: A
authors.initials: A
authors.lastname: Van Stewart
authors.forename: R H
authors.initials: RH
authors.lastname: Staat
mesh_terms: D018441:Biofilms / Q000187:drug effects; D002384:Catalysis; D015169:Colony Count, Microbial; D019551:Dental Disinfectants / Q000494:pharmacology*; D003748:Dental Equipment; D006861:Hydrogen Peroxide / Q000494:pharmacology; D016877:Oxidants / Q000494:pharmacology; D011549:Pseudomonas / Q000302:isolation & purification; D013291:Streptococcus / Q000302:isolation & purification; D014871:Water Microbiology
chemical_list: D019551:Dental Disinfectants; D016877:Oxidants; D006861:Hydrogen Peroxide