Should dentists mandatorily wear ear protection device to prevent occupational noise-induced hearing loss? A randomized case-control study

Objectives: Dentists are constantly exposed to high-frequency noise at their workplace that increases the risk of occupational noise-induced hearing loss (ONIHL). Even though dentists acknowledge about the noisy dental workplace, hearing protection devices or ear protection devices (EPD) are not commonly used by dentists. No study has yet provided any evidence on how effective EPDs can be in reducing the temporary threshold shift and damage to the outer, middle and inner ears. The aim of this article is to evaluate and compare the changes in the hearing acuity and temporary threshold shift (TTS) in dentists who wear EPDs when compared with those who do not use EPDs. Materials and Methods: Sixty-four dental clinicians were randomly divided into two groups: Group 1 (performed ultrasonic scaling without EPDs) and Group 2 (performed ultrasonic scaling with EPDs). Their hearing threshold was checked by using pure tone audiometry, stapedial acoustic reflexes, and otoacoustic emission (OAE) before and after 45 mins of ultrasonic scaling. The intergroup and intragroup comparison was done. All the outcome measures from pre- and post-scaling across the ears, groups, and frequencies among groups were done using mixed-effects analysis of variance. A P-value of less than 0.05 was considered to be statistically significant. Results: EPDs were effective in reducing the immediate TTSs. Immediately upon exposure to high-frequency noise, the alterations in the hearing threshold and stapedial reflex OAE were less in the group that used EPDs. Conclusion: EPDs should be mandatorily worn by dentists to prevent accumulation of temporary shifts in the hearing acuity, which in long-term can lead to permanent hearing loss.