Abstract
Although handpieces are used in various dental practices, no simple and reliable sterilization process for them has been established.The final solution to this problem is to develop disposable instruments, but this is a difficult task due to their precise inner structure.We report the development of air turbine handpieces using plastic journal bearings with hydrodynamic lubrication for the realization of disposable dental handpieces.Their rotational properties were investigated to examine their clinical usefulness.The speed achieved with the handpiece using plastic bearings was about 85% of that using ball bearings under the freerunning condition and 80% in stopping torque.The handpiece was applied to the preparation of extracted human teeth and it was found to have cutting ability satisfactory for clinical usage.
