Noise Levels in Dental Offices and Laboratories in Hamedan, Iran

Noise pollution is one of the most important situations requiring a solution by the contemporary world. The National Institute for Occupational Safety and Health has identified noise as one of the ten leading causes of work-related diseases and injuries. Dentists and dental auxiliaries are exposed to different noise levels while working in dental offices or laboratories. The purpose of this study was to measure the noise level made by different dental instruments in dental offices and laboratories. Measurement of the noise level was performed in 89 dental offices and nine dental laboratories. The noise levels were determined using a sound level meter; type SL-4011 (Lutron), which was placed at the operator''s ear level in dental offices and laboratories and also at two-meter distance from the technician''s ear in laboratories. The maximum sound level was 85.8 dB in dental offices and 92.0 dB in laboratories. In dental clinics, the highest noise was produced by the ultrasonic-scaler (85.8 dB) and the lowest noise (49.7 dB) by the high-volume aspirator, whereas in the laboratory, the highest noise was caused during grinding by the stonecutter (92.0 dB) and the lowest by the denture-polishing unit (41.0 dB). After close evaluation, we believe that the maximum noise level in dental offices, although often beneath the damaging noise level for the human ear, is very close to the limit of hearing loss (85.0 dB). However, laboratory technicians may be at risk if they choose not to wear ear protection (earplugs or earmuffs).