title: Internal contamination of air-driven low-speed handpieces and attached prophy angles.
abstract: BACKGROUND
  In an in vitro crossover study, the authors investigated whether the interior of low-speed handpiece/prophy-angle systems becomes contaminated during operation and submersion into Geobacillus stearothermophilus.
  
  
  METHODS
  This study involved two types of handpieces attached to eight brands of prophy angles. The researchers operated angles attached to sterile handpieces for 60 seconds. They then analyzed the inside surfaces of the angle, nosecone and motor. They tested each prophy angle and handpiece 10 times.
  
  
  RESULTS
  In the 160 tests of handpieces contaminated at the prophy cup end, the spores traveled into the motor gears 32 times (20 percent). In the other 160 tests in which the motor gears were contaminated, the test bacterium traveled through the prophy cup in 75 instances (47 percent).
  
  
  CONCLUSIONS
  The in vitro data suggest that low-speed handpiece motors can become contaminated internally during use with prophy angles. Also, internal contaminants appear to have been released from the handpiece.
  
  
  CONCLUSIONS
  The results suggest that low-speed hand-pieces can become contaminated internally during use. Unless low-speed handpieces are sterilized properly between patients, they may become cross-contaminated.
authors.affiliation: Oral Health Research Institute, School of Dentistry, Indiana University, 415 Lansing St., Indianapolis, 46202, USA. jchin@iupui.edu
authors.forename: Judith R
authors.initials: JR
authors.lastname: Chin
authors.forename: Chris H
authors.initials: CH
authors.lastname: Miller
authors.forename: Charles John
authors.initials: CJ
authors.lastname: Palenik
mesh_terms: D018592:Cross-Over Studies; D003754:Dental High-Speed Equipment / Q000382:microbiology*; D045302:Geobacter / Q000302:isolation & purification; D019552:Infection Control, Dental