Sex Pistols lead singer John Lydon has been pilloried for shelling out $22,000 to fix the decaying gnashers that inspired his nickname Johnny Rotten. "It wasn't vanity that sent me to the dentist," he has said in his defence. "All those rotten teeth were seriously beginning to corrupt my system. I was feeling incredibly ill. I was permanently poisoning myself with gum infections. My gums were receding and I was starting to look seriously weird."
Perhaps punk fans should go easy on him. It was reported last week, in a study published in Lancet Oncology, that periodontitis (gum disease) could be associated with an increased risk of lung, kidney, pancreatic and haematological cancers, while previous research has suggested a link with illnesses such heart disease, diabetes and stroke. But why would the state of your teeth affect the rest of your body?
In the latest study, researchers at Imperial College, London, found that men with a history of gum disease had a 14% higher chance of cancer compared with those with no history of gum disease. One theory is that an immune system weakness causes both illnesses. There is even a possibility that the bad bacteria from infected gums might cause the cancer when it is swallowed. At this stage, however, these are all mere possibilities. "This study doesn't confirm whether it is gum disease or other factors that are causing this small increase in risk," says Hazel Nunn of Cancer Research UK. For instance, she says, "People from deprived backgrounds are more likely to have both poor dental health and poor overall health."
Whether people with poor gum health should worry about stroke or heart disease is also not clear-cut. It may be that the bacteria that causes gum disease also causes an inflammation and narrowing of artery walls. Another theory is that some of us are predisposed to developing inflammation in response to both plaque and fatty deposits in blood vessel walls. However, says Dr Philip Preshaw, senior lecturer in periodontology at Newcastle University, "while early studies indicated apparently very strong associations between heart disease, stroke and periodontal disease, some suffered from methodological weakness and more recent studies have failed to show the same level of evidence." Similarly, research that linked gum disease with gestational diabetes has suggested that the inflammation could interfere with the normal functioning of insulin, but this research is in its infancy, so while pregnant women should visit the dentist regularly (it is free for them), anxiety about diabetes would be overkill.
What dentists know for sure is that people with diabetes are more likely to develop gum disease, as are smokers. "Diabetes affects blood vessels and immune processes so that your body cannot fight infections as well," says Preshaw. Smoking also affects immune responses.
There are two main forms of gum disease. Gingivitis is the inflammation and bleeding of the gums caused by bacterial plaque on the tooth's surface (pink spit when brushing your teeth, red gums and bad breath are key signs). "Gingivitis is reversible with improved oral hygiene," says Preshaw. "You need to see a hygienist who will remove the plaque that causes the inflammation, and you then need to clean your teeth more effectively." If plaque is not removed, it can turn into calculus (tartar), a hard layer on the surface of the tooth. With periodontitis, the more advanced form, the body's immune system fights the harmful bacteria, but this constant battle damages tissue that supports the tooth. Teeth then begin to "drift" away from the bone, loosen or fall out. Indicators of periodontal disease include gum swelling, discharge, or gaps opening up between the teeth. The damage it causes is irreversible - however, it can be stabilised with better brushing and a method of cleaning by a hygienist known as "root planing", which removes plaque. In severe cases, dentists may have to extract teeth, and some sufferers need gum surgery.
All of this is scarily common: 40-60% of the population has gingivitis or mild periodontitis, while approximately 10-15% of us have advanced periodontitis.
Dentists already know how abysmal we are at looking after our teeth, but a survey by the British Dental Health Foundation has found that we commonly use penknives, screwdrivers or scissors to pick food from them, and when faced with bleeding gums, around half of us will ignore the problem, or just brush softly.
According to the foundation, the most effective brushing technique involves tilting your toothbrush to a 45-degree angle against the gumline. Use circular movements on all teeth surfaces, and brushing your tongue will also help to remove bacteria. Flossing once daily is also recommended.
Gum disease can affect anyone - even those who brush angelically and visit their dentist regularly. "Gum health involves a complex interplay between bacteria and the body's immune responses against those bacteria," he says. "If any part of the immune system is out of balance, you may be more susceptible to gum disease." Dental hygiene reduces your risk but some people are more genetically prone, and since gum disease is largely painless, people are often unaware of the problem. So next time you're spitting blood, don't ignore it or you could end up resembling the old John Lydon.
