TNF and Peri-Implantitis: Diabetes increased the mRNA expression of TNFα (Fig. 4a), IL1β (Fig. 4b), and IL-17 (Fig. 4c) in peri-implant gingival tissues (DM vs. WT), and peri-implantitis further upregulated the expression levels of these pro-inflammatory proteins (DM+lig vs. DM).