Receding gums in gum disease. Close-up of the mouth of a person with gum (periodontal) disease that has caused a loss of the gum tissue around the lower (mandibular) teeth. Gum disease is most often caused by inadequate dental hygiene, allowing bacteria to build up between the teeth and below the gumline. This leads to chronic inflammation and gradual recession of the gums. In severe cases the underlying bone can be eroded leading to loosened teeth and ultimately tooth loss.