Published: 12-06-2012 00:00 | Updated: 10-06-2015 11:12

Dental plaque may increase risk of cancer

Persistent dental plaque may increase the risk of dying early from cancer, suggests an observational study published in the online journal BMJ Open. In the study, which was conducted by researchers at Karolinska Institutet and Helsinki University, the health of almost 1,400 randomly selected Swedish adults was tracked over a period of 24 years.

Dental plaque is made up of a film of bacteria, which covers the surfaces of the teeth, including the gaps between the teeth and gums. It leads to tooth decay and gum inflammation, with the potential for tooth loss.

All participants of the current study were in their 30s and 40s at the start of the monitoring period in 1985, when they were all quizzed about factors likely to increase their cancer risk, such as smoking and levels of affluence. Their mouth hygiene was also assessed to find out what levels of dental plaque, tartar, gum disease, and tooth loss they had. While they had no overt gum disease, they did have substantial levels of plaque on the tooth surface.

By 2009 about 4.2 per cent of the participants had died. The average age of death was 61 for the women and 60 for the men. Poor mouth hygiene linked to 80 per cent increased risk after accounting for other influential factors. Deaths among the women were predominantly caused by breast cancer, while those among the men were attributed to a range of different cancers.

In other words persistent dental plaque that poor mouth hygiene, as reflected in the amount of dental plaque, may be associated with increased risk of cancer and early death, the researchers conclude. Further studies are required to determine whether there is any causal element in the observed association.


The association of dental plaque with cancer mortality in Sweden. A longitudinal study.
Söder B, Yakob M, Meurman J, Andersson L, Söder P
BMJ Open 2012 ;2(3):