Therefore, the purpose of this study was to investigate the effect of green tea on the spontaneous onset of diabetes-triggered periodontitis based on the quantitative and spatial evaluation of TNF-α, RANKL, IL-10, runt-related transcription factor 2 (RUNX-2), and osteoprotegerin (OPG) immunostaining patterns, as well as assessment of the oral microbiotic load, in the periodontal tissues of rats at 15, 30, 60 and 90 days after diabetes induction. The gene discussed is RUNX2; the disease is diabetes mellitus.