Early Outer Hair Cell Dysfunction Associated With Educational Noise Exposure in Dental Students: Implications for...

Dental education involves continuous exposure to high-frequency noise from clinical instruments, which may cause early outer hair cell damage even before professional practice begins. While noise-induced hearing loss (NIHL) is a recognised occupational hazard among dentists, evidence regarding subclinical outer hair cell changes during undergraduate training remains limited. As this study did not include a non-dental, age-matched control group, the observed differences are reported as an association with year of dental education rather than as proof of a causal effect of educational noise exposure.

This comparative cross-sectional study evaluated 140 dental students: 88 first-year and 52 fifth-year at Biruni University. Pure-tone and high-frequency audiometry, transient-evoked otoacoustic emissions (TEOAE) and distortion product otoacoustic emissions (DPOAE) were measured to assess auditory function. Environmental noise levels in preclinical and clinical settings were recorded over an 8-h period using calibrated sound level meters.

Average noise exposure was 77.1 dB in preclinical and 81.2 dB in clinical settings. While no significant differences were observed in conventional audiometric frequencies, fifth-year students showed significantly elevated hearing thresholds at 9-20 kHz (p < 0.05). TEOAE and DPOAE signal-to-noise ratios were markedly reduced in fifth-year students, indicating early outer hair cell dysfunction (reduced cochlear amplifier function).

These findings reveal subtle yet measurable outer hair cell changes associated with advancing dental education. Such early alterations, undetectable by standard audiometry, suggest that dental training environments may pose a latent risk for NIHL.

This study provides early evidence of an association between advancing dental education and subclinical outer hair cell dysfunction in dental students, emphasising the need to integrate hearing conservation and noise-awareness education into dental curricula to protect future professionals' auditory health.