title: A pilot study of 2 methods for control of dental unit biofilms.
abstract: OBJECTIVE
  This pilot study was conducted to clinically evaluate 2 different concentrations of sodium hypochlorite for the control of dental unit biofilms and to evaluate the efficacy of pasteurizing dental treatment water for patient care.
  
  
  METHODS
  Two dental units with no prior chemical treatment were retrofitted with self-contained water systems for this study. One dental unit was treated with 5,000 ppm of sodium hypochlorite and the other with 1,500 ppm. Treatment consisted of a 10-minute contact with the dental unit water lines, followed by a flush with a buffer solution. A pasteurizer was equipped with autoclavable spigots to provide dental treatment water. Heterotrophic Plate Count Samplers (Millipore) water sampler kits were used to quantify microbial contamination as absolute colony-forming units per millimeter. Scanning electron micrographs were taken of water line lumens to compare pretreatment and posttreatment biofilms.
  
  
  RESULTS
  Pasteurized water was significantly less contaminated than was tap water. No significant difference in contamination was found between the 5,000 ppm and 1,500 ppm treatment chairs, either in the reservoir water or effluent water. Scanning electron micrographs demonstrated removal of the biofilms after sodium hypochlorite treatments, regardless of the concentration used.
  
  
  CONCLUSIONS
  There was no significant difference between the abilities of 5,000- and 1,500-ppm concentrations of sodium hypochlorite to control contamination of dental treatment water and biofilms. Pasteurization of tap water can reduce contamination; this water can be used as acceptable dental treatment water (< 200 CFU/mL).
authors.affiliation: Baylor College of Dentistry, Texas A & M University Health Science Center, PO Box 660677, Dallas, Texas 75266-0677, USA.
authors.forename: P J
authors.initials: PJ
authors.lastname: Kim
authors.forename: R A
authors.initials: RA
authors.lastname: Cederberg
authors.forename: R
authors.initials: R
authors.lastname: Puttaiah
mesh_terms: D018441:Biofilms / Q000254:growth & development; D015169:Colony Count, Microbial; D003748:Dental Equipment / Q000382:microbiology*; D004202:Disinfectants / Q000008:administration & dosage / Q000627:therapeutic use*; D004866:Equipment Contamination / Q000517:prevention & control*; D006358:Hot Temperature; D006801:Humans; D008851:Micropore Filters; D008855:Microscopy, Electron, Scanning; D010865:Pilot Projects; D012973:Sodium Hypochlorite / Q000008:administration & dosage / Q000627:therapeutic use; D013242:Sterilization / Q000379:methods; D014871:Water Microbiology; D018508:Water Purification / Q000379:methods
chemical_list: D004202:Disinfectants; D012973:Sodium Hypochlorite