Screening of dental staff nurses for noise induced hearing loss

The effect of noise on employees of dental clinics is debatable. The purposes of this study were to determine the intensity and frequency components of dental instruments used by dental staff nurses and the prevalence of noise induced hearing loss.

We performed a comparative, cross sectional study on a group of dental staff nurses. Participants underwent ear examination followed by pure tone audiometry. Pure tone audiometry was performed at least 48 hours after the participants were free from noise exposure. Noise induced hearing loss was defined as failed definitive threshold at a frequency of 4000 Hz greater than 20 dB. The intensity level, noise spectrum, and frequency of hand piece, saliva suction, and scaler were recorded during the dental procedure.

A total of 65 dental staff nurses were included. The mean intensity of hand pieces, scalers, and saliva suctions were 88.7 (SD2.2), 87.1 (SD2.6), and 77.4 (SD6.3) dBA while their most prominent frequencies were 3880, 7997, and 3513 Hz, respectively. Three of the subjects had slightly more than 20 dB hearing loss at 4 kHz on audiogram; all were affected unilaterally. These three individuals worked as dental nurses for 11, 13, and 21 years, respectively. Therefore, the prevalence of noise induced hearing loss was 5.0% (95% CI: -1.0%, 10.0%).

Dental staff nurses might have an increased risk of noise induced hearing loss, depending upon individual factors influencing susceptibility and duration of noise exposure.