[Are professional dental health care workers (dentists, dental technicians, assistants) in danger of noise induced hearing loss?].

BACKGROUND: Rotating instruments in dentistry are radiating an unpleasant high-frequency noise, which was supposed to produce hearing loss by its loudness. Therefore frequently notifications and recognizing procedures were initiated because of the suspicion of occupational noise-induced hearing loss (German listing for occupational diseases as given by decree: Number 2301). In recent years dentists, dental technicians and dental assistants repeatedly had to be tested because of a suspicion for noise-induced inner ear damage.

METHODS: Noise measurements were performed in 3 working places of dentists and 7 dental laboratories.

RESULTS: In regard to dentists and dental assistants it was found that the aspirator, not the rotating instruments, was the most intense source for noise in the office. The averaged daily noise level was measured between 70 and 77 db(A) and was therefore obviously below the inner ear damaging limit of 85 dB(A). For dental technicians the on-site related averaged daily noise level was about 68 dB(A) and the person related averaged daily noise level was about 76 dB(A). In some particular cases 80 dB(A) were exceeded, but relevant levels for an occupational noise trauma were not reached. It has to be taken into consideration that the rotating instruments got a considerable noise reduction in the last decade. Additionally it has to be taken into account for the calculation that the averaged running time of rotating instruments is 30 minutes per day in the office. Therefore, a notification or a recognizing procedure can regularly stand aside.

CONCLUSION: An endangering by noise as given by the German occupational disease decree (more than 85 db(A)) cannot usually be expected for the dentist, the dental assistant and the dental technician.