A Swedish research study – published June 11 in the British Medical Journal Open – states that dental plaque may increase the risk of early cancer death by as much as 80 percent.

About 1,400 people from Stockholm – age 30 to 40 – with no signs of gum disease took part in the study – conducted by researchers at the Karolinska Institute and the University of Helsinki – to see if oral hygiene had an impact on cancer mortality. Each person received an oral health assessment and answered questions such as how often they visited their dentist; whether or not they smoked; their level of education; how much money they earned; and their levels of dental plaque, tartar, gum disease and tooth loss.

After a 24-year follow-up – in 2009 – the amount of people that had died and the cause of their death were determined using national death and cancer records. Fifty-eight people died and 35 of the deaths were cancer-related. The average age at death was 60 for men, who died of a variety of cancers, and 61 for women. One third of the deaths occurred in women, the majority of whom died of breast cancer. These were all considered premature deaths because the women were expected to live about 13 years longer and the men an additional 8.5 years. Those who died had higher dental plaque index values – .84 to .91 – than those who lived – .66 to .67. This indicates that plaque had covered the gum area of the teeth in the individuals who died.

The Key Findings:

  • Dental plaque increased the risk of early cancer death by 79 percent.
  • Participants with the most bacteria on the surface of their teeth and gums had an 80 percent increased risk of premature death.
  • A link was found between high levels of dental plaque or bacteria and dying from cancer up to 13 years earlier than might otherwise be expected.


While the researchers admit their findings do not prove a causal link between cancer and dental plaque, they suggest that poor mouth hygiene may be an indicator of other lifestyle factors associated with cancer. The authors caution that this study does not prove that dental plaque either contributes to or causes cancer. “Our study hypothesis was confirmed by the finding that poor (mouth) hygiene, as reflected in the amount of dental plaque, was associated with increased cancer mortality,” the study says. “Further studies are required to determine whether there is any causal element in the observed association.”

“In this study, the people who died as a result of cancer had a greater amount of dental plaque build-up than those who were still alive at the end of the study or died of other causes,” said Dr. Brian Franks, Clinical Director, Dentistry, Bupa Health and Wellbeing. “A lot can happen in peoples’ lives and their mouths over 24 years. There is no doubt that good oral hygiene is important; if plaque build-up is left for a long time, it can lead to tooth loss and gum disease. But whether or not it causes cancer death is yet to be proven.”

The Recommendations
Dr. Frank’s recommendations to avoid plaque build-up that leads to tooth decay and gum disease are to:

  • Brush your teeth twice a day for two minutes and pay attention to your gum line.
  • Use dental floss or interdental brushes to remove plaque and small bits of food from between your teeth.
  • Avoid sugary foods and drinks.
  • Visit your dentist regularly to spot potential problems early and prevent them from getting worse.



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