Observational prospective study to determine the association and diagnostic utility of salivary nitrite levels in periodontitis

Objective: It has been found that patients with chronic periodontitis showed higher salivary concentrations of reactive nitrogen species than healthy subjects. However, only a study of elderly Koreans has reported that high salivary reactive nitrogen species concentrations are associated independently with periodontitis. The objective of the present study was to determine whether salivary nitrite concentrations are associated with periodontitis-controlling risk factors in other populations (such as a European population). Method and materials: This was a prospective and observational study carried out in a dental clinic including European subjects without periodontitis (including subjects with periodontal health or with localized gingivitis in 30% sites) or with periodontitis (thus, with loss of periodontal tissue). The levels of nitrite in saliva were assessed using the Griess method. A multivariate regression analysis was performed to determine that variables were associated independently with periodontitis. To determine the association between salivary malondialdehyde levels and the severity of periodontitis, Spearman rho correlation coefficient was used. A receiver operating characteristic analysis with salivary nitrite levels and periodontitis diagnosis was performed.
Results: Subjects with periodontitis (n = 54) in comparison to subjects without periodontitis (n = 30) had higher salivary nitrite levels (P = .003), a higher rate of arterial hypertension history (P = .02), and were older (P .001). Nevertheless, differences between subjects with and without periodontitis in other variables were not found. A positive correlation was found between salivary nitrite levels and periodontitis severity (rho = 0.23; P = .04). Multiple logistic regression analysis showed that elevated salivary nitrite levels > 209 nmol/mL were associated with periodontitis, controlling for arterial hypertension history and age (OR = 10.212; 95% CI = 2.665 to 39.128; P = .001) and controlling for diabetes mellitus and smoking (OR = 8.793; 95% CI = 3.038 to 24.450; P .001). The area under the curve for periodontitis diagnosis by salivary nitrite levels was 69% (95% CI = 58% to 79%; P .001). The selected point of salivary nitrite levels > 209 nmol/mL for periodontitis diagnosis had 72% sensitivity (58% to 84%), 77% specificity (58% to 90%), a 3.1 positive likelihood ratio (1.6 to 6.1), 0.4 negative likelihood ratio (0.2 to 0.6), 85% positive predictive value (74% to 92%), and 61% negative predictive value (49% to 71%).
Conclusions: Salivary nitrite concentrations could be associated independently with periodontitis, could be associated with periodontitis severity, and could help in periodontitis diagnosis in a European population according to the results of this preliminary study. (Quintessence Int 2025;56:100–107; doi: 10.3290/j.qi.b5872791) Keywords: gingivitis, nitric oxide, nitrites, oxidation, periodontitis, salivary