Discussion
PD, bleeding, periodontitis, periodontium
SYSTEMIC DISEASE, BLEEDING, PERIODONTITIS, CHRONIC PERIODONTITIS, PLAQUE, TYPE 2 DIABETES
The present research is one of the first studies to investigate the effect of resveratrol supplementation on periodontitis. In this double-blind study with a placebo control, the effectiveness of resveratrol as a supplementary treatment for clinical indicators (PD, CAL, PI, and BI) and salivary inflammatory indicators (IL-8 and IL-1β) was investigated in chronic periodontitis patients without any systemic disease.According to the results, there were no significant differences between the control and experimental groups in gender and age; in this regard, the two groups were homogenous. According to the comparisons between the two groups, after four weeks of resveratrol supplementation in the experimental group, the only clinical indicator with a significant decrease compared to the control group was plaque index (PI) (P = 0.0001). However, there were no significant differences between the two groups in pocket depth (PD), clinical attachment level (CAL), bleeding index (BI), and IL-8 and IL-1β levels in salivary samples (Table In this research, the changes in PD levels were not significantly different between the experimental and control groups, which is different from the results of a study by Zare et al. (2017), who investigated the effect of resveratrol on 43 patients with type 2 diabetes and chronic periodontitis over four weeks [Several studies have investigated the effect of non-surgical periodontal treatments, such as oral hygiene instructions, scaling, and root planning, as the key treatments for these patients [In the four weeks of the study, CAL decreased by 1.23 mm in the experimental group and 1.8 mm in the control group; these changes are statistically significant (Table The O’Leary plaque index significantly decreased in both the experimental and control groups compared to the baseline (P = 0.0001), and it also significantly decreased in the experimental group compared to the control group (P = 0.0001) (Table In this study, the bleeding index (BI) significantly decreased in both groups after four weeks (P = 0.0001). However, there was no significant difference between the two groups (P = 0.2), which might be due to the significant effect of non-surgical periodontal treatment, frequent oral hygiene instructions, and the Hawthorne effect in both groups that can diminish the effectiveness of resveratrol.The salivary IL-1β levels decreased significantly in both the experimental and control groups compared to the baseline; however, there was no significant difference between the two groups after the intervention (P˃0.05). Casati et al. (2013) treated 10-week-old rats with 10 mg/kg of daily resveratrol and measured IL-1β, IL-7, and IL-4 levels. They did not observe any significant difference between the two groups in IL-1β and IL-4 levels, but IL-7 levels decreased in the resveratrol treatment group compared to the control group (receiving placebo) [Several studies have reported an increase in the salivary or gingival crevicular fluid IL-8 levels in inflamed areas compared to healthy areas. In contrast, some other studies have suggested decreased IL-8 levels in inflamed areas. Therefore, the results are contradictory [Although the mentioned evidence suggests the treatment potential of resveratrol in the host inflammatory modulation, the primary mechanism causing this effect is still unknown. Oral treatment with resveratrol has limited bioavailability, and it is quickly affected by metabolism. Its local treatment or injection might have a higher anti-inflammatory effect on the periodontium. Therefore, although the immunologic findings of this study do not suggest the modulation of immune-inflammatory responses by resveratrol, its molecular mechanism should be studied further. The limitations of the present study included the small number of sample size and short follow-up period. Further studies with larger sample size and longer follow up periods needed to explore the impact of resveratrol supplementation on clinical parameters and inflammatory markers in periodontitis patients.