Background/Objectives: Patients with periodontitis have been found to have higher salivary concentrations of malondialdehyde, a biomarker of lipid hyperoxidation, compared to healthy subjects. However, the association between salivary malondialdehyde levels and periodontitis, independently of other risk factors, has not been analyzed. Therefore, the novel objective of our study was to explore this possible association by performing a logistic regression analysis. Material and Methods: This observational, prospective study was carried out in a private dental practice. Salivary malondialdehyde levels were measured in subjects with periodontitis (characterized by periodontal tissue loss) and in subjects without periodontitis (either periodontally healthy or with localized gingivitis in <30% of sites). A multivariate regression analysis was carried out to determine the factors associated with periodontitis. Variables with a p-value ≤ 0.05 in the comparison between subjects with and without periodontitis were included in the regression analysis. Results: A total of 119 subjects were included, 63 with periodontitis and 56 without (35 periodontally healthy subjects and 21 patients with localized gingivitis). In the multiple binomial regression analysis, salivary malondialdehyde levels > 0.77 nmol/mL were identified as a predictor of periodontitis (p = 0.03), after controlling for age (p < 0.001), diabetes mellitus (p = 0.81), arterial hypertension (p = 0.43), smoking status (never smoked p = 0.08), and cardiovascular disease (p = 0.88). Conclusions: To our knowledge, this is the first study to report that salivary malondialdehyde levels are associated with periodontitis, independently of other known risk factors.

Background: Tyrosine, a non-essential amino acid involved in protein biosynthesis, can undergo oxidative modification upon exposure to reactive species like the peroxynitrite radical (ONOO⁻), resulting in the formation of 3-nitrotyrosine (3-NT). High concentrations of 3-NT have been found in the periodontal tissues of rats with periodontitis and in one study involving twelve patients with periodontitis; further, a correlation between 3-NT concentrations in periodontal tissues and clinical indices of periodontitis was found in 24 patients with periodontitis. The objectives of our study were to compare salivary 3-NT concentrations in subjects with and without periodontitis, to determine whether an association exists between salivary 3-NT concentrations and periodontitis, and to evaluate the potential of salivary 3-NT concentrations for the diagnosis of periodontitis. Material and Methods: This prospective study involved the measurement of salivary 3-NT concentrations in individuals diagnosed with periodontitis—defined by the presence of periodontal tissue loss—and in individuals without periodontitis, characterized by either periodontal health or localized gingivitis affecting fewer than 30% of sites. A total of 66 participants without periodontitis and 60 with periodontitis were included. To identify variables independently linked to periodontitis, multivariate logistic regression was applied. Additionally, a receiver operating characteristic (ROC) analysis was carried out to assess the ability of salivary 3-NT levels to discriminate between the two groups. Results: Multivariate logistic regression analysis showed that the variables independently associated with periodontitis were salivary 3-NT concentrations > 4.25 ng/mL (OR = 3.22; 95% CI = 1.180–8.789; p value = 0.02), age (years) (OR = 1.12; 95% CI = 1.064–1.168; p value < 0.001), and being a never smoker (OR = 0.36; 95% CI = 0.129–0.989; p value = 0.048). The area under the curve (AUC) of salivary 3-NT concentrations for the diagnosis of periodontitis was 62% (95% CI = 53–70%; p value = 0.02). Conclusions: Our findings showed that salivary 3-NT concentrations were higher in subjects with periodontitis than in those without, that there is an association between high salivary 3-NT concentrations and periodontitis, and that salivary 3-NT concentrations may be useful for diagnosing periodontitis.

Background: Sirtuin-1 (SIRT-1) is one enzyme that has anti-oxidative, anti-inflammation and anti-apoptosis effects, and it is involved in regulating aging and in different age-associated disorders. Salivary SIRT-1 concentrations in periodontitis patients have been scarcely studied and only in studies with small sample sizes (the highest with 83 subjects). There were no differences in salivary SIRT-1 concentrations between periodontitis patients and periodontally healthy subjects in any of those studies. The aims of our study were to compare salivary SIRT-1 concentrations in subjects with periodontitis and those without it in a study with a larger sample size to determine whether there exists an association between salivary SIRT-1 concentrations and the presence of periodontitis and to analyze the potential capability of salivary SIRT-1 concentrations for periodontitis diagnosis. Material and Methods: In this cross-sectional study, salivary SIRT-1 concentrations were measured in subjects with and without periodontitis. To determine that variables were associated with periodontitis, a multivariate logistic regression analysis was carried out. To determine the capability of salivary SIRT-1 concentrations to diagnose periodontitis, a receiver operating characteristic (ROC) analysis was carried out. Results: We included 144 subjects (85 without periodontitis and 59 with periodontitis). Salivary SIRT-1 concentrations < 1.2 ng/mL were associated independently with periodontitis (OR = 2.84; 95% CI = 1.075–7.506; p = 0.04) in the regression analysis. The salivary SIRT-1 concentration showed an area under curve of 74% (95% CI = 66–86%; p < 0.001) for periodontitis diagnosis in the ROC analysis. Conclusions: Our study had the highest sample size reporting salivary SIRT-1 concentrations in patients with periodontitis. We found that low salivary SIRT-1 concentrations could be associated with the presence of periodontitis. In addition, they could play a role in periodontitis diagnosis as an adjunct to other markers given that their diagnostic capability is not high. However, given the limitations of our study, further investigations are necessary to confirm these preliminary findings.