The more dental plaque you've got, the more likely you are to die prematurely of cancer, according to a new study.
Researchers from Sweden examined 1390 people between 1985 and 2009. Each participant underwent an oral examination and was questioned about their lifestyle risk factors, such as socioeconomic status and smoking.
By the end of the study period, 58 patients had died, 35 of whom died from cancer. The people who died had significantly more dental plaque than the survivors.
The researchers used the dental plaque index to measure the amount of plaque in the participants' mouths. Those who died had values of 0.84 to 0.91, which shows the gums were covered with plaque.
Those who survived had values of 0.66 to 0.67, which suggests the gum area only had some parts covered with plaque.
On average, the women who died were 61, while the men were 60, which is significantly lower than average life expectancies of 74 for women and 68.5 for men. Therefore the study authors concluded their deaths were premature.
"Based on the present findings, the high bacterial load on tooth surfaces and in gingival pockets over a prolonged time may indeed play a role in carcinogenesis," the study authors wrote.
"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. Further studies are required to determine whether there is any causal element in the observed association."
Dr Peter Alldritt, chairman of the Oral Health Committee of the Australian Dental Association, says poor oral health has been linked to other health problems.
"More research needs to be done on this specific link, however there are links between having good oral health and having good systemic health," he says.
"There have been a lot of publications showing people with cardiovascular disease are more likely to have gum disease. Problems in the oral cavity in the mouth can [lead to] a higher risk of problems elsewhere in the body."
Dr Alldritt says it’s crucial we brush our teeth morning and night and floss daily.
"To maintain good oral health and lower the amount of bacteria and plaque in your mouth, which were the risk factors for this link to cancer, you've got to have good oral hygiene at home," he says.
"In Australia there are an increasing amount of people only brushing once a day it's a big no no. You really need to brush your teeth twice a day to lower your chance of gum disease and tooth decay."
He also suggests brushing your tongue daily or using a scraper to remove bacteria.