Teeth cleaning in 200 feet Radial road Gum Disease Explained Gum disease is caused by bacteria that gets below your gums and creates “pockets” where even more bacteria can collect. As your body tries to fight this infection, it begins breaking down the tissue and bone surrounding your teeth. You’ll likely have tender, inflamed gums in the early stages of gum disease, called gingivitis. As the disease progresses, it destroys not just tissue but bone. This stage is called periodontitis, and it’s when you can begin losing teeth.