The assessment of glutathione, glutathione peroxidase, glutathione reductase, and oxidized glutathione in patients with periodontitis—A systematic review and meta‐analysis

Objective The present systematic review explored the involvement of enzymatic and nonenzymatic antioxidants in periodontitis, drawing from established literature. Materials and Methods The research approach encompassed an extensive electronic search from 2000 to 2023 across databases such as PubMed, Science Direct, and Wiley Online Library and cross‐referencing using specific keywords. Results The initial literature exploration generated a total of 766 articles. After thoroughly examining the s, 693 articles were excluded from consideration due to duplication and lack of relevance to the central research inquiry. Following that, 73 articles were left for in‐depth evaluation. Following a qualitative assessment, 35 studies that satisfied the inclusion criteria were chosen, while 38 were removed for not meeting the necessary standards. Within this selection, a meta‐analysis was conducted on 11 articles that provided consistent data for quantitative synthesis. Specifically, the analysis of glutathione (GSH) levels in serum samples revealed a standardized mean difference (SMD) of −5.552 µg/mL (CI 95%: −9.078 to −2.026; P‐0.002). In contrast, the analysis of glutathione peroxidase (GPx) enzymes in gingival crevicular fluid (GCF) samples displayed an overall SMD of 2.918 ng/µL (CI 95%: 0.372–5.465; P‐0.025), while salivary samples exhibited an overall SMD value of 0.709 U/l (95% CI: −1.907–3.325; P‐0.596) which is of insignificant. Conclusion The systematic review findings suggest a notable decrease in antioxidant enzymes across various systemic biological samples among patients with periodontitis, contrasting with the results from gingival tissue samples meta‐analysis of GPx enzyme.