[Noise-induced hearing loss caused by dental turbines]

Sound level measurements and third octave analyses were carried out to estimate the risk of hearing impairment caused by working the turbine drills. Idling noise of two turbines equipped with ball-bearings and air-bearings respectively and the effects of different burs under varying load conditions in particular were examined. Finally, the background sound level in a great consulting room of a dental clinic at medium activity was looked at. Without any exception the sound levels were situated below 85 dB (A). The sound level exceeded 80 dB in only a few third octave bands; this was the case only with the antiquated ball-bearing turbine. Working with turbine drills requires only a fraction of the total treatment duration, resulting in a very low equivalent sound level. As a consequence a hearing impairment risk may be excluded within the reach of this investigation.