GPNMB and periodontitis: Seven proteins such as matrix metalloproteinase, Interleukin [(L)‐1α, IL‐1β, IL‐8, osteoactivin, osteoprotegerin and C‐reactive protein] were significantly upregulated in patients with periodontitis compared to healthy controls. The highest diagnostic accuracy using a ROC curve was observed for IL‐1β. Linear discriminant analysis had the highest classification accuracy across the five tested classification models.