Gum disease, also known as periodontal disease, is a serious condition in which the gums and bone around the teeth are infected. This infection is caused by plaque and tartar. This in turn can eat away at the gums and bone and cause irreversible damage to your mouth. 
Gum disease starts with the formation of plaque. When you eat starchy or sugary foods, it mixes with your saliva and becomes food for bacterial plaque. When this bacterial plaque is not removed properly with regular and effective brushing and flossing, it gains strength as it accumulates around the gum line. This causes inflammation of the gums, also known as gingivitis. Eventually, it causes bone loss, which is known as periodontitis. The most serious ramifications of gum disease, if left untreated, is tooth loss. This is an irreversible result of extreme periodontal disease.