*2.6. Statistical Analysis*

Data were entered and analyzed using SPSS (IBM Statistics software version 21, New York, NY, USA). For average comparison among exposure time, Kruskal–Wallis analysis was applied to each of the bacteria (*E. coli*, *S. aureus* and *S. mutan)* by treatment and growth time as CFU count were not normally distributed. The Mann–Whitney test was applied for pair-wise comparison of each exposure time with treatment and growth time controlled. A *p*-value of < 0.05 was considered as statistically significant.
