Effects of Dental Noise on Dentists' Performance and Stress Responses: A Randomized Crossover Trial.

OBJECTIVE: To investigate the effect of continuous noise generated during dental treatment on dentists' performance and stress responses. METHODS: This study involved a questionnaire survey and an experimental investigation. The questionnaire survey was conducted with 44 dentists to assess dental noise-related subjective burden and noise sources perceived as the most uncomfortable. In the experimental phase, a randomized crossover trial was performed with 11 participants under silent and noisy conditions. Work performance was evaluated using the total number of calculations (work volume) and error rates in the Uchida-Kraepelin test. Saliva samples were collected before, during, and after the test, and salivary alpha-amylase (sAA), chromogranin A (CgA), and secretory immunoglobulin A (sIgA) levels were measured to assess stress responses. RESULTS: In the questionnaire survey, clinical noise was perceived as uncomfortable by 93.2% of dentists, with the extraoral suction unit being identified as the most unpleasant device (equivalent continuous noise level: 91.7 ± 0.6 dBA). In the randomized crossover trial, work volume in the Uchida-Kraepelin test significantly decreased, and the error rates significantly increased, under the noisy condition. With respect to salivary stress markers, sAA levels were significantly higher under the noisy condition, and sIgA levels were significantly increased. By contrast, CgA levels did not significantly differ between the conditions. Furthermore, sAA levels were significantly correlated with work performance. CONCLUSIONS: Dental noise reduced dentists' performance and elicited stress responses. These findings highlight the need for noise mitigation and occupational stress management strategies in dental practice.