A Passive Noise Attenuation Earplug Designed to Minimise Unwanted Air Turbine Driven High-Speed Dental Drill Noise.

Introduction: Air turbine dental drill noise contains high-frequency components that are of concern for patients and dental staff. Meanwhile, verbal communication between the dentist and patient is essential. Conventional active noise-cancelling headphones are ineffective for dental drill noise and simply suppress all sound and hinder communication.

Method: A compact passive earplug device was designed specifically to attenuate broadband high-frequency noise ranges from 5 to 8 kHz employing an array of quarter wavelength (QW) resonators. This device was 3D printed and tested against white noise to enhance the objectivity of analysis, using a calibrated ear and cheek simulator to effectively measure its performance.

Results: The results showed that the resonators produced an average reduction of 27 dB across the targeted frequency range. When compared with two proprietary passive earplugs, this developed passive device prototype was able to attenuate an average of 9 dB more across the target frequency range whilst delivering louder speech signals of 14 dB more. The results also show that using an array of resonators exhibits an accumulated effect of individual resonator performance.

Conclusions: This low-cost passive device could have a place in the dental clinic to reduce unwanted drill noise equivalent to the white noise high frequency spectra tested.