The toxins released by the bacteria in dental plaque which has accumulated along the gum margin for a period of time irritate the periodontal tissues (tooth supporting tissues) and lead to gum disease.
Animation showing the release of toxins by bacteria in dental plaque accumulated along the gum margin that leads to red and swollen gums. Photograph of a set of teeth, with red and swollen gums on the front teeth and the accumulation of dental plaque and calculus along the gum margin.
Under the following situations, you are prone to having gum disease or making the condition worse:

Accumulation of dental plaque
Photograph of a wearing denture that is not thoroughly cleaned. Wearing dentures that are not thoroughly cleaned
Dental plaque and food debris easily accumulate in the space between the denture and the gingivae (gums).
Photograph of teeth with accumulation of calculus. Accumulation of calculus
The rough surface of calculus allows dental plaque to build up more easily.
Photograph of a set of irregular teeth. Irregular teeth
The irregular alignment of teeth makes it difficult to clean these teeth.
Smoking

Smokers have up to five times greater chance to suffer from gum disease than non-smokers.Smokers are more prone to gum disease because:

  • Early symptoms of gum disease is less noticeable in smokers

    Smoking makes early symptoms of gum disease such as swollen gums and bleeding while brushing less noticeable because chemicals in cigarettes such as nicotine cause blood vessel constriction. As the bleeding symptom is not obvious, it is not easy to discover that the gingivae have been inflamed. As a result, the gum disease will aggravate unconsciously.

  • Smoking lowers the body resistance and therefore lowers the healing capability of patients with gum disease

    Nicotine in cigarettes lowers the healing capability of oral tissues, retards the healing process and causes the gum disease to worsen.

Stress

Stress lowers the body resistance towards illnesses including gum disease.

Hormonal changes during pregnancy
Photograph of the oral condition of pregnancy gingivitis showing severely red, swollen and bleeding gums.
If pregnant women do not clean their oral cavity thoroughly, the hormonal changes during pregnancy may exaggerate the response of the gum tissues to the plaque bacterial toxins, resulting in red, swollen and bleeding gums. This is called “Pregnancy Gingivitis".
Systemic diseases

Systemic disease such as diabetes mellitus, leukaemia and AIDS lower the resistance of the tooth surrounding tissues towards bacterial infection. Bacteria inside the dental plaque will intrude and cause gum disease if the oral cavity is not thoroughly cleaned. Furthermore, the healing capability is also lowered in patients suffering from these diseases and it is more difficult for them to recover from gum disease. Therefore, gum disease is more progressive and severe in these patients.

Intake of medications

Intake of medication such as anti-hypertensive and anti-convulsant drugs stimulate the multiplication and activity of fibroblasts (a type of cells) in the gingivae and causes gingival swelling. Dental plaque that accumulates in the swollen gingivae is difficult to be cleaned, which leads to more severe gingival inflammation and further swelling.