title: [Comparison of preventive effects of two kinds of dental handpieces on viral contamination at different rotating times].
abstract: OBJECTIVE
  It has been demonstrated that when a high-speed handpiece stops rotating, negative pressure will form. Thus, contaminating fluid in which there are many kinds of bacteria and viruses from the external environment will retract into various compartments of the handpiece and the dental unit. The purpose of the study is to compare the preventing effect of antisuction designed handpiece and conventional handpiece on viral contamination at different rotating times.
  
  
  METHODS
  Twenty handpieces with or without antisuction device (10 of each) were used in the study. Each handpiece was submerged into 10(-6) microg/microl HBV particle solution rotating 5 and 10 times respectively (every time rotating for 10 seconds). Samples were obtained from the water line and chip air line of the handpieces and examined by RT-PCR.
  
  
  RESULTS
  At the same rotating times, there was statistical significance of the viral concentration between the two kinds of handpieces (P < 0.05) . However, there was no statistical significance of the viral concentration between different rotating times in each group (P > 0.05).
  
  
  CONCLUSIONS
  Contamination taking place in both water and air lines of dental handpiece was not enhanced by increasing the number of rotating times of the handpiece. The antisuction devices installed into the water line and chip air line were demonstrated to prevent viral contamination effectively.
authors.affiliation: Dept. of Oral Medicine, West China College of Stomatology, Sichuan University, Chengdu 610041, China.
authors.forename: Tao
authors.initials: T
authors.lastname: Hu
authors.forename: Yu-ling
authors.initials: YL
authors.lastname: Zuo
authors.forename: Xue-dong
authors.initials: XD
authors.lastname: Zhou
mesh_terms: D003754:Dental High-Speed Equipment / Q000821:virology*; D004866:Equipment Contamination / Q000517:prevention & control*; D013396:Suction