A LABORATORY EVALUATION OF 2 BRANDS OF DISPOSABLE AIR TURBINE HANDPIECE

Objective To report on the essential performance characteristics of tw o brands of disposable air turbine handpiece and on aspects of their s afety and convenience for clinical use. Materials and methods Oralsafe and Feathertouch disposable handpieces were characterised using a var iety of techniques in respect of the following: turbine rotor radius, equivalent orifice radius, stall torque coefficient, pressure effectiv eness, power index, efficiency index, sound level and instrument reten tion force. Results Free-running speed versus pressure curves for many of the disposable handpieces showed marked deviations from the expect ed smooth form. Considerable variation between examples of each type w as found in most measured values. Evidence of eccentric rotors and hig h bearing friction was not found. Conclusions Both brands of disposabl e handpiece had a number of problems: poor performance, vibration, exc essive noise, variability of behaviour, poor bearings. Use of these de vices is difficult to recommend. Improvement in design seems necessary .