HIF1A and periodontitis: Periodontitis has been linked to hypoxia, which is a recognized risk factor, and studies documented a marked consequent elevation in the HIF-1α expression in saliva, gingival crevicular fluid, periodontal ligament cells, and gingival tissue adjacent to the periodontal pocket.13, 22, 23, 24, 25Moreover, there is growing evidence of its correlation with abundant inflammatory biomarkers.