Periodontal or gum diseases begin as a buildup of plaque near the gum line on the tooth’s surface. If this plaque is not removed by regular cleanings, brushing, and flossing regularly, it can harden into tartar. Plaque will continue to build over the tartar, eventually causing your gums to become inflamed, red, swollen, and irritated. The first step of this disease is called gingivitis. It later evolves into periodontal disease.