The aim of the present follow-up study was to verify the incidence on the development of type 2 diabetes in women with previous gestational diabetes with and without periodontitis after a three-year time interval, and to quantify CRP in the blood as well as TNF-α, IL-6, interleukin 10 (IL-10), matrix metalloproteinase 2 (MMP-2), and matrix metalloproteinase 9 (MMP-9) in the saliva. The gene discussed is MMP9; the disease is type 2 diabetes mellitus.