The objective of the present study was to assess the effects of occupational exposure to noise and organic solvents on hearing loss in bus and truck plant workers. Our case control study contained 469 workers from a bus and truck plant divided into three groups. The first group contained workers exposed to only noise; the second group contained workers exposed to both noise and mixture solvents at a permissible level; and the third group included workers exposed to permissible levels of solvents. The control group (Group 4) included 119 individuals selected randomly, persons who were not exposed to noise and solvents. These groups were compared in terms of each individual's frequency hearing loss in both ears. Our study demonstrates that combined exposure to mixed solvents and noise can exacerbate hearing loss in workers. Hence, a suitable hearing protection program is advised that would contain short-interval audiometric examinations and efficient hearing protectors.

Aim: Dental technicians are exposed to noise and chemical hazards that may lead to hearing loss in workplace. The aim of this study is to investigate the hearing loss risk of dental technicians working in dental laboratories. Material and Methods: A hundred and five dental laboratory technicians who applied to Ankara Occupational Diseases Hospital for periodic check and 120 control subjects were included in the study. All of the subjects in both the dental technician and control groups were male. Audiograms of dental laboratory technicians was compared with audiograms of control subjects. Mann Whitney-U test and Spearman correlation analysis were used for statistical analysis of data. Results:The hearing threshold values of the dental technicians at all frequency in both ears were found to be significantly higher than the control group. There were statistically significant correlation between age and hearing thresholds at all frequencies (except at 250 Hz and 1000 Hz) in dental technician group. There were statistically significant correlation between age and hearing thresholds at only 4000 Hz and 8000 Hz in control group. It was found that there were statistically significant correlations between exposure time and hearing thresholds at 2, 4 and 8 kHz frequencies in dental technician group. Conclusion:Results of this study indicate that hearing loss is a serious occupational health problem in dental technicians. Dental technicians are exposed to noise and chemical hazards that may constitute a risk for hearing loss. Dental technicians must take preventive measures for hearing loss during working.