Table 2.
Experimental design.
| Reference | Duration | Experimental Design | Measurement of Vitamin C | Main Results | ||
|---|---|---|---|---|---|---|
| Dosage | Administration | Frequency | ||||
| Gumus, 2009 [66] | 2 and 1/2 years | none | none | none | measurement of antioxidants’ salivary concentrations in whole saliva samples | Subjects with type 2 DM had fewer teeth and more sites with probing depths (>4 mm) than patients with type 1 DM. Despite this, total antioxidant capacity and vitamin C concentrations did not seem to play a major role in the pathogenesis of periodontitis correlated with DM. |
| Thomas, 2010 [65] | Not mentioned | none | none | none | venous blood samples collected | Diabetic patients with periodontitis revealed a significant decrease in vitamin C levels. |
| Gokhale, 2013 [63] | 4 months | 450 mg | subgroups randomly divided using a coin-toss method: subgroup A (15) 450 mg chewable tablet and subgroup B (15) placebo chewable tablet | daily intake for 2 weeks or only SRP | plasma measurement | Plasma measured AAL were below the normal range in systemically healthy subjects with gingivitis and diabetics with periodontitis. Dietary AA supplementation associated with SRP improved the SBI in patients with gingivitis and PD–DM. |
| Amaliya, 2015 [68] | 1 year | food products categorized as high (>60 mg), fair (31–60 mg), low (2–30 mg) or no vitamin C (<2 mg vitamin C/100 g) | Number of guava fruit servings | food frequency taken in the last month | plasma measurement, based on the values provided by the National Nutrient Database for standard reference | 45% of the participants showed vitamin C depletion/deficiency, 70% were in a prediabetic state, 6% had untreated diabetes. Still, it has been shown that guava fruit consumption might have played a protective role against periodontitis in a malnourished population, regarding the extent and severity of ABL (at least 10% of the participants had a low BMI and were considered as malnourished). |
| Patil, 2016 [67] | 1 year | none | none | none | plasma measurement | A significant decrease in vitamin C was observed in the diabetic periodontitis group as compared with healthy control groups. Type 2 diabetic subjects revealed excessive ROS concentration, therefore more periodontal tissue destruction. |
| Kunsongkeit, 2019 [64] | 2 months | 500 mg | tablets | daily for 2 months | plasma measurement | Periodontitis patients with uncontrolled type 2 DM did not have evident benefits by supplementation of 500 mg/day vitamin C. |
Abbreviations (in alphabetical order): ABL—alveolar bone loss, AA—ascorbic acid, AAL—ascorbic acid levels, BMI—body mass index, DM—diabetes mellitus, PB—probing depth, PPDs—probing pocket depths, ROS—reactive species of oxygen, SBI—sulcus bleeding index, SRP—scaling and root planning.