The particles generated during tooth preparation were separated according to their sizes, the concentration in different locations of the room and the efficiency of the HEOS unit was examined. For different PM values two-way ANOVA results showed in Table 1.
Table 1
Two way ANOVA results for different PM values
| 0,3 µm | 0,5 µm | 1 µm | 2 µm | 5 µm | 10 µm |
| P-value | P-value | P-value | P-value | P-value | P-value |
Corrected Model | 0.001 | 0,001 | 0.001 | 0.001 | 0.001 | 0.001 |
Intercept | 0.001 | 0.001 | 0.001 | 0.001 | 0.001 | 0.001 |
Location | 0.001 | 0,530 | 0,074 | 0,100 | 0,005 | 0,024 |
Group | 0.001 | 0.001 | 0.001 | 0.001 | 0.001 | 0.001 |
Location * Group | 0.001 | 0,417 | 0,032 | 0,078 | 0,014 | 0,033 |
For PM0.3 values, there was a signficant effect of both location (P = 0.001) and groups (P = 0.001) on PM values. Interaction of group and location was also significant (P = 0.001). According to post-hoc test for interaction, there was no statistically significant difference between the locations measured in group 1 for PM0.3 values. There was a statistically significant difference between group 1 and group 2 in all four locations (P = 0.001). That is to say, the HEOS unit reduced the particle concentration of 0.3 microns in all four locations. There was a statistically significant difference in all four regions between the PM0.3 values in group 1 and group 2 and there was an apparent increase (Fig. 1).
For PM0.5 values, no difference between locations (P = 0.530) but significant difference between groups (P = 0.001) was found. Interaction of group and location wasn’t statistically significant (P = 0.417). There was a statistically significant difference between group 1 and group 2 (P = 0.001). In group 2, PM0.5 values increased apparently. There was a statistically significant difference between group 2 and group 3 (P = 0.001). In group 3, PM0.5 values decreased apparently (Fig. 2). There was no significant difference between the group 1 and group 3 (P = 0.574).
For PM1.0 values, no difference between locations (P = 0.074) but significant difference between groups (P = 0.001) was found. Interaction of group and location was also statistically significant (P = 0.032). There was a statistically significant difference between group 1 and group 2 (P = 0.001). In group 2, PM1.0 values were increased. There was a statistically significant difference between group 2 and group 3 (P = 0.001). In group 3, PM1.0 values were decreased (Fig. 3). There was no significant difference between the group 1 and group 3. In group 3, The highest decrease in PM1.0 value was observed in the center of the room.
For PM2.0 values, no difference between locations (P = 0.100) but significant difference between groups (P = 0.001) was found. Interaction of group and location wasn’t statistically significant (P = 0.078). There was a statistically significant difference between group 1 and group 2 (P = 0.001). In group 2, PM2.0 values were increased. There was a statistically significant difference between group 2 and group 3 (P = 0.001). In group 3, PM2.0 values were decreased (Fig. 4). There was no significant difference between the group 1 and group 3 (P = 0.162).
For PM5.0 values, there was a signficant effect of both location (P = 0.005) and groups (P = 0.001) on PM values. Interaction of group and location was also significant (P = 0.014). According to post-hoc test for interaction, In group 1, there was no statistically significant difference between locations. In group 2, there was a statistically significant difference between locations, the maximum PM5.0 value is chest of patient, chest of dentist, center of the room and near the window, respectively. In group 3, there was no statistically significant difference between locations. There was a statistically significant difference between group 2 and group 3 in all four locations (P = 0.001). HEOS unit reduced particles of 5 microns in all four locations. There was a statistically significant difference in all four locations between group 1 and group 2, and there is a significant increase (Fig. 5).
For PM10.0 values, there was a signficant effect of both location (P = 0.024) and groups (P = 0.001) on PM values. Interaction of group and location was also significant (P = 0.033). According to post-hoc test for interaction, there was no statistically significant difference between the locations in group 1. There was a statistically significant difference between the locations in group 2, the maximum PM10.0 value is chest of patient, chest of dentist, center of the room and near the window, respectively. In group 3, there was no statistically significant difference between locations. There was a statistically significant difference between group 2 and group 3 in all four locations (P = 0.001). HEOS unit reduced particles of 10 microns in all four locations. There was a statistically significant difference in all four locations between group 1 and group 2, and there is a significant increase (Fig. 6).
When the general descriptive statistics are examined, PM0.3 value averages were listed as group 3 with the lowest, followed by group 1 and group 2. In group 3, the highest decrease was seen in PM10.0 and PM5.0 values compared to the group 2. This was followed by PM2.0, PM1.0, PM0.5, and PM0.3, respectively. According to these findings, the HEOS unit is more effective as the particle size increases. When the HEOS unit was running, the mean values of the 0.3 and 0.5 micron particles decreased compared to the first measurement in the empty room, the mean value of the 1.0, 2.0, 5.0 and 10.0 micron particles decreased in group 3 compared with group 2, but increased compared with group 1.