Noise-induced hearing loss in dental surgeons : the Maltese perspective

Abstract

Dental surgeons are exposed to several occupational hazards during their daily practice, amongst which is noise, generated by equipment used in dental clinics. Such noise exposure may lead to hearing loss. The aim of this study was to investigate hearing loss among dental surgeons registered and practising in Malta (n=129), with special reference to occupational noise-induced hearing loss. Noise levels in dental clinics were measured so as to check whether they exceeded levels set by the European Agency for Safety and Health at Work. The study adopted a quantitative research design. It is a cross-sectional, structured, non-experimental study, partly using a survey, and partly using a descriptive correlational (ex post facto) design retrospectively. The first part of the study involved a questionnaire. Eligible dentists were invited to have their hearing assessed via a pure-tone audiogram and the noise-levels at the dental clinics where they practised measured. The final cohort consisted of 40 dentists. These had a prevalence of hearing loss of 2.5%, however, 35% showed noise-induced auditory changes, most commonly at 4000 Hz, followed by 6000 and 3000 Hz. Males had worse thresholds than females but this was statistically significant only for the left ear. Deteriorating hearing thresholds were positively correlated to number of years in active dental practice, the latter being a predictor of high-frequency hearing loss. The mean background noise level was found to be 55.5 dBA, higher than the recommended value for public areas in hospitals/clinics. The mean noise level whilst dental instruments were in use was 76.7 dBA. This did not exceed permissible levels, in agreement with other similar studies reported in the literature. Given that more than one third of the participants still had noise-induced changes, a more proactive approach towards noise reduction and hearing conservation should be adopted.