A recent systematic review and meta-analysis by Wang et al. focused on oxidative biomarkers in peri-implant sulcular fluid, and reported significantly decreased glutathione peroxidase (GSH-Px), elevated myeloperoxidase (MPO), and increased MDA levels in peri-implantitis, with standardized mean differences ranging from –1.40 for GSH-Px to +0.46 for MPO and +0.28 for MDA [17]. This evidence concerns the gene MPO and Peri-Implantitis.