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

INTRODUCTION: 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. MATERIALS AND METHODS: 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. RESULTS: 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). DISCUSSION: 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. CONCLUSIONS: 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.