Psychoacoustic analyses of noise in dental environment

Abstract

Introduction: Noise in dental environments (NDE) is unwanted or unpleasant sound that is created during dental services. The poor sound quality (SQ) of the NDE may have various negative impacts on both dental professionals (DP) and patients. Psychoacoustics, a branch of psychophysics, scientifically studies the psychological impacts of sounds more than mere loudness sensation. Although the high-energy and high-frequency properties of the NDE are highlighted in the previous studies, the psychoacoustic approach is a novel way to quantitatively characterise the SQ and the perceptual influence of the NDE. The knowledge of the human-environmental interactions is essential for the future noise management.

Objectives: i) To investigate the negative impacts of the NDE on the DPs in the psychoacoustic approach; ii) To systematically investigate and synthesize the fundamental structure of the perceptual dimensions of sounds from the existing studies; iii) To develop a psychometric tool in characterising the principal perceptions of sounds; v) To analyse the associations of the perceptual influence of the NDE and the patient’s dental anxiety (DA).

Methods: The noise exposure assessments that embraced the measurements of the acoustic and psychoacoustic metrics were conducted together with the noise impact assessments to evaluate the impacts of the NDE on the DP. Bivariate and multivariate statistical analyses were applied to test the associations between the objective and subjective data. The acoustic studies that involved subjective measurements of perceptions of sounds were systematically searched from the online databases. Different validity and reliability tests were applied to test the psychometric properties of the designed psychoacoustics perception scale (PPS). The patient's perceptions of the NDE was assessed by the PPS and the effects of the negative perceptions on the DA were also tested.

Results: The psychoacoustic studies showed that: i) The degree of the perceptual influence from the noise from dental instruments (NDI) was correlated with N, rho = 0.34, p = 0.008. ii) The score of the short-term impacts of the NDE on the DP was increased by 4.3 units (p < 0.001) with 1-acum increment of the S. iii) The hearing state of the DP with daily working hours (DWH) >= 8 hr and service length (SL) >= 10 yr was found to be the worst. iv) The underlying structure of the perceptions of sounds (EPA model) was synthesized by the meta-analysis and was further verified. v) The PPS is a reliable and valid psychometric tool to assess the EPA model. vi) The MDAS score of the subjects was increased by 0.27 units (p = 0.003) with a unit increment of the score of the latent factor Evaluation (E).

Conclusion: The negative impacts of the NDE on the DP and the patients were evidenced by the psychoacoustic analyses. The shot-term impacts mainly came from the temporal and spectral characteristics of the NDE. The long-term impacts were more related to the energy characteristics of the NDE. The needs of the psychoacoustic approach for the assessments, control, and prediction of the NDE were demonstrated in this work.