Gingival index (GI)
The mean GI scores at baseline (GI-0) in the intervention and placebo groups were 1.28 and 1.22, respectively, but this difference was not statistically significant (p = 0.392). The mean GI at four weeks (GI-3) were 0.86 and 0.23 in the intervention and placebo groups, respectively, in which this difference was statistically significant (p = 0.006). According to the results of the Friedman test, during the study time, the changes in GI score had a statistically significant decreasing trend in both groups (p = 0.001) (Table 