WHAT CAUSES GUM DISEASE? The condition you may refer to as “gum disease” also is called “periodontal disease.” Periodontal disease is an inflammation of the gums that, if severe, can lead to the loss of the tissues that hold your teeth in place. It is caused by plaque, a sticky film of bacteria that forms constantly on teeth. You can remove plaque by brushing twice a day and cleaning between your teeth daily. If plaque is not removed, it can cause your gums (gingivae) to pull away from your teeth, forming pockets in which more bacteria can collect. Plaque that is not removed also hardens into calculus along and under your gums. The pockets and hard calculus make it difficult to remove plaque without help from a dentist, and periodontal disease can develop. If left un - treated, periodontal disease can damage the tissues that support your teeth, even the bone.