Gum disease, as it worsens, progresses from a0 to a1. next question ask for turn it in

According to the National Institute of Dental and Craniofacial Research, gum disease or periodontal disease is the infection of the tissue that holds teeth, which is cause by high presence of bacteria that forms plaque. Some of the symptoms of gum disease are:

The gum disease can begin with gingivitis, which is the inflammation of the tissue that holds teeth, causing easy bleeding and red colour of gum. The worst stage of gum disease is necrotizing periodontal disease, which is an infection involving dead gum tissue, it can be caused by immunodeficiencies, malnutrition, physical and psychological stress, smoking, or a genetic causes.