Is salivary melatonin an indicator of periodontal disease severity? A systematic review and meta-analysis

To evaluate, through a systematic review and meta-analysis, the differences in salivary melatonin (S-MEL) levels between individuals with periodontal disease and healthy individuals.

A systematic search was conducted in PubMed, EMBASE, SciELO, LILACS, and BIREME following PRISMA 2020 guidelines and PROSPERO registration. Human studies comparing patients with periodontal disease with healthy controls and reporting S-MEL were included. Screening occurred in two phases. Meta-analysis was performed in Jamovi using the MAJOR module, applying the standardized mean difference (SMD) (Hedges g), a random-effects model, heterogeneity statistics, and publication bias tests. Seventeen comparisons were included.

The random-effects model showed significantly lower S-MEL levels in patients with periodontal disease (SMD = -2.04; 95 % confidence interval [CI] -3.44 to -0.63; p = 0.005), with high heterogeneity (I² = 97.8 %). Notably, most studies reported reduced melatonin levels, despite a few positive effects. Funnel plot asymmetry and Begg/Egger tests suggested publication bias, although trim-and-fill revealed no missing studies. The high fail-safe N supported the robustness of the findings.

S-MEL levels were consistently lower in patients with periodontal disease, suggesting a potential biomarker relationship. Despite the substantial heterogeneity, the overall evidence supports this association. However, further standardized studies are needed.