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.
Materials and 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.