Metformin-treated gingiva showed significantly lower gene expression levels of inflammatory markers related to periodontal disease progression [39] Tnf-α (− 2.7 fold; p = 0.005) and Caspase 3 (− 2.3 fold; p = 0.011), as well as lower expression of reparative markers important to reconstruct the periodontium [40] Igf-1 (− eightfold; p = 0.036) and Axin2 (− 2.5 fold; p = 0.004), suggesting a more normal (homeostatic) gingival tissue (Fig. 2B). Here, TNF is linked to periodontal disorder.