Gum Disease, also known as periodontal disease, is an infection of the tissues that surround and support the teeth. It is caused by the accumulation of plaque (a sticky film of bacteria) on the teeth, which leads to inflammation and infection in the gums. Gum disease can progress in stages, ranging from gingivitis (a mild form) to more severe forms like periodontitis, which can result in tooth loss if left untreated.