title: A laboratory evaluation of two brands of disposable air turbine handpiece.
abstract: OBJECTIVE
  To report on the essential performance characteristics of two brands of disposable air turbine handpiece and on aspects of their safety and convenience for clinical use.
  
  
  METHODS
  Oralsafe and Feathertouch disposable handpieces were characterised using a variety of techniques in respect of the following: turbine rotor radius, equivalent orifice radius, stall torque coefficient, pressure effectiveness, power index, efficiency index, sound level and instrument retention force.
  
  
  RESULTS
  Free-running speed versus pressure curves for many of the disposable handpieces showed marked deviations from the expected smooth form. Considerable variation between examples of each type was found in most measured values. Evidence of eccentric rotors and high bearing friction was not found.
  
  
  CONCLUSIONS
  Both brands of disposable handpiece had a number of problems: poor performance, vibration, excessive noise, variability of behaviour, poor bearings. Use of these devices is difficult to recommend. Improvement in design seems necessary.
authors.affiliation: Department of Prosthetic Dentistry, University of Hong Kong, Prince Philip Dental Hospital, Hong Kong.
authors.forename: J E
authors.initials: JE
authors.lastname: Dyson
authors.forename: B W
authors.initials: BW
authors.lastname: Darvell
mesh_terms: D000399:Air Pressure; D003754:Dental High-Speed Equipment; D004209:Disposable Equipment; D004526:Efficiency; D011211:Electric Power Supplies; D004867:Equipment Design; D005069:Evaluation Studies as Topic; D010969:Plastics; D012399:Rotation; D019415:Torque; D014732:Vibration
chemical_list: D010969:Plastics