# Evaluation of Noise Levels in a University Dental Clinic
## 4 Results  
### Description of Results  
Table 3 shows data gathered from measurement positions. Spectrum analysis of noise at previous sites during the measurement periods is presented in Figures 4-10. In these figures, Leq (or LAeq) represents the equivalent continuous sound pressure level. Figure 3: The Solo 01 dB-Metravb and the two Bruel and Kjaer Noise Dose Meters (Type 4436) were calibrated prior to testing noise measurements. Figure 4: Spectrum analysis of workplace noise at position 4P (center of the UG1). \begin{table}
\begin{tabular}{c c c c c c c} \hline
**Position** & **Clinic/Laboratory** & **Method** & **LA** & **M.Peak dB(C)** & **Time (Min)** & **LeqdB(A)** \\ \hline \multirow{3}{*}{1P} & UG1, & \multirow{3}{*}{Personal measurement} & \multirow{3}{*}{102.5} & \multirow{3}{*}{119.4} & \multirow{3}{*}{67} & \multirow{3}{*}{78.5} \\  & hand instruments, & & & & & \\  & ariotor/micmotor & & & & & \\  & UG2 & \multirow{3}{*}{Personal measurement} & \multirow{3}{*}{101.1} & \multirow{3}{*}{128.5} & \multirow{3}{*}{73} & \multirow{3}{*}{74.5} \\
2P & hand instruments, & & & & & \\  & ariotor/micmotor & & & & & \\  & UG2 & \multirow{3}{*}{Personal measurement} & \multirow{3}{*}{108.6} & \multirow{3}{*}{119.6} & \multirow{3}{*}{58} & \multirow{3}{*}{80.8} \\
3P & ultrasonic handpiece, hand instruments & & & & & \\  & UG1S & Static & & & & \\
4P & all sounds & measurement & & & & \\  & UG2S & Static & & & & \\  & all sounds & measurement & & & & \\
5P & all sounds & measurement & & & & \\  & UG2S & Static & & & & \\
6P & all sounds & measurement & & & & \\  & PG1 & Static & & & & \\
7P & all sounds & measurement & & & & \\  & PG2 & Static & & & & \\  & all sounds & measurement & & & & \\
8P & all sounds & measurement & & & & \\  & PG2 & Personal & & & & \\
9P & ultrasonic handpiece and & & & & & \\  & hand instruments & & & & & \\  & LAB1 & Static & & & & \\
10P & ariotor, acrylic cutting & measurement & & & & \\  & LAB1 & Personal & & & & \\
11P & ariotor/micmotor & dosemeters & & & & \\  & LAB2 & Personal & & & & \\
12P & ariotor/micmotor use & & & & & \\  & LAB2 & Static & & & & \\
13P & ariotor/micmotor & measurement & & & & \\ \hline \end{tabular}
\end{table} 
Table 3: Data from measurement positions of the study. Figure 5: Spectrum analysis of workplace noise at position 5P (center of UG 2S). Figure 6: Spectrum analysis of workplace noise at position 6P (center of UG 2S). The data show that work-related noise levels are within the recommended range discussed by Presidential Decree No.149/2006 [49] and the Directive 2003/10/EC [48]. Figure 8: Spectrum analysis of workplace noise at position 8P (chairside PG 2A). Figure 10: Spectrum analysis of workplace noise at position 13P (center of LAB 2S). Figure 9: Spectrum analysis of workplace noise at position 10P (center of LAB 1S). The mean noise levels in the working clinics and laboratories ranged from 47.0 dB(A) to 80.8 dB(A). Overall, in the post-graduate (PG) clinic, there were significant differences in noise levels (\(p>0.05\)) between the chairside (personal exposure measurement by dosimeters worn by students) (54.6-71.7 dB(A)) and the points of static measurements (area monitoring) (47.0-63.5 dB(A)) with airotor/micmotor/suction use at certain times and in comparison to settings with new dental units (1 year in use). In the undergraduate (UG) clinic, noise levels with suction and high/slow speed handpieces at the center of the clinics were highly significant for all the maximum readings (\(p=0.001\)) between clinics with old equipment (25 years old units, UG1, vs. 15 years old units, UG2) [56.3-68.4 vs. 59.8-70.4 dB(A)]. Also, personal exposure measurements with the use of an ultrasonic handpiece were significantly different in UG1 vs. UG2 [54.5-102.5 dB(A)] vs. [47.5-101.2 dB(A)], respectively) (\(p>0.05\)). Suction alone in the UG clinic [63-75 dB(A)] was significantly quieter than that in the PG clinic [69-79 dB(A)].