# Evaluation of Noise Levels in a University Dental Clinic
## 1 Introduction
Further, there may be music playing in the practice. Exogenous sources include noise from the external environment (e.g., vehicle traffic from outside and work in construction areas). It is also widely accepted that noise during clinical dental practice creates negative emotions in the clinicians and dental staff, such as nervousness, loss of concentration, and restlessness, but at the same time exacerbates anxiety in phobic patients [5]. Previous studies have shown that the noise levels produced in a dental office in dB(A) are less than 80 dB(A), which is within the permissible limits set by the WHO. WHO recommends that noise exposure levels should not exceed 70 dB over a 24 h period and 85 dB over a 1 h period to avoid hearing impairment [35]. However, there are variations in the measurements in different dental environments, resulting in different factors that determine the noise levels that can be recorded. These variations can be attributed to the different methods used. For example, in a study conducted by Songkla University [36], the personal noise dose in the hearing zone was estimated using a decibel meter attached to participants, instead of the noise level in the working areas. The second method involved recording the noise in each minute by obtaining a mean period, in contrast to the method described in the study by [PERSON] et al. [37], where only the peak of noise every 5 min was recorded. In a study by [PERSON] et al. [38], conducted at the Oxford Hospital and Oxford School of Dentistry, Bangalore, Kantaka, the level of noise of the cutting devices was measured using a microphone placed near the operator's ear, close to the main noise source. The minimal intensity and the maximal intensity of noise were assessed for 30 s using the dental devices triggered only during the cutting moments when the intensity of noise ranged from 64 to 97 dB. In some studies, the environment was also assessed [36],reporting that the level of noise was slightly higher than that recorded in the hearing zone. The common part of all relevant studies is that the level of noise that really damaged the hearing of students could be a little lower than that registered in the dental clinic, but at times very high in frequencies temporarily surpassing the control limits [36; 37; 38]. Other relevant studies report on the differences in equipment used for the measurements of noise levels [39; 40; 41; 42]. So far, there has not been enough evidence of the differences in noise levels between different university clinics or laboratories due to years of use of dental equipment, settings, and tasks performed. Further, no noise spectra during dental clinical work have been reported so far. Thus, the purpose of this research is to (a) measure noise levels within different clinics and laboratories of the Department of Dentistry of the National and Kapodistrian University of Athens, which contain dental equipment of different ages of use; (b) present spectrum analysis of noise variations during workflow in clinics and laboratories; (c) promote possible necessity of information sharing regarding this serious health issue among stakeholders; and (d) collect data to enhance preventive measures for students and personnel (faculty members, collaborators, administrative, and technical staff).