What is Periodontal (gum) Disease? Periodontal disease is something that effects a large portion of the population. It is a disease that causes pockets or spaces in the gum tissue, allowing bacteria to enter. The build up of plaque causes the gums to become inflamed and form these pockets. Normal brushing cannot reach this build up and over time the pockets continue to get deeper. Symptoms may include bad breath, red and puffy gums, bleeding gums and loose or sensitive teeth.