Gum disease can be more than just painful; new research suggests it can also lead to tongue cancer.

Researchers at the University of Buffalo and Roswell Park Cancer Institute say they have found a possible link between chronic periodontitis, or gum disease, and the risk of developing tongue cancer.

The study, published in the May issue of the Archives of Otolaryngology, found the risk of tongue cancer due to chronic periodontal disease increased fivefold with every millimetre of lost alveolar bone -- the bone in the jaw that holds teeth in place.

The researchers compared panoramic dental X-rays of 51 males newly diagnosed with tongue cancer against those of 54 men without cancer. Bone loss measurements were made by the same periodontist, who did not know the cancer status of any of the participants.

After adjusting for potential effects of age, smoking status and the number of existing teeth, researchers found that the men with chronic gum disease were 5.2 times more likely to have tongue cancer with every millimetre of bone loss than those without gum disease.

What's more, the link between periodontal disease and tongue cancer existed even among non-smokers, the researchers concluded.

"This association needs to be confirmed by larger studies using quantitative assessment of lifetime tobacco exposure," the authors write in the study.

"If this association is confirmed, it has a potential impact on understanding the etiology of oral cancer as well as on its prevention and control."

Periodontal disease begins when the bacteria in plaque -- the sticky, colourless film that forms on teeth -- causes the gums to become inflamed. If the bacteria are allowed to multiply, it can start to erode alveolar bone, leading to pain and tooth loss.

An estimated 15 per cent of Canadian adults have the condition to varying degrees.

It's not known why precisely gum disease can lead to cancer, but it's thought that the enzymes and toxins produced by mouth bacteria can cause genetic alterations in specific cells in the tongue, which then become cancerous.

Signs of tongue cancer include white or red lesions that don't heal, unlike canker sores.

The best way to prevent periodontal disease is with regular oral hygiene: regular brushing, flossing and dentist visits.