Gum disease and ulcers are a pair, perhaps even a pair of opposites. Gum disease often precedes an ulcer, but many people develop ulcers before their gums start to bleed. The condition can be caused by physical injury, stress, or infection from dental work, but it also happens with very few teeth.

Like periodontitis, gum disease is a condition that weakens the immune system. People who have periodontal disease or gum disease are more likely to develop ulcers in their mouths. A study conducted in the early 1980s found that the chance of developing oral ulcers was 10 times greater for people with periodontal disease. And research published in 2009 showed that gum disease was associated with a higher risk for ulcerative stomatitis.