Daily tooth brushing and annual dentist visits may reduce the risk of some head and neck cancers by a small margin, according to a recent, large study.
“A few smaller studies have shown a link between a few oral hygiene indicators and cancer in the past,” said lead author Dr. Dana Hashim of the department of preventive medicine at Icahn School of Medicine at Mount Sinai in New York.
“I would argue that it is appropriate to say that this is a causal relationship because this study uses incident - that is, newly diagnosed cases of cancer, after oral hygiene indicator data was collected,” Hashim told Reuters Health by email.
The researchers combined data from 13 studies including a total of almost 9,000 mouth, pharynx or similar tumor patients and more than 12,000 comparison subjects without cancer. The studies were done in the Americas, Europe and Japan.
In all of them, oral hygiene was assessed based on gum disease or bleeding, missing teeth, daily tooth brushing, visiting a dentist at least once per year and whether a person wore dentures.
People with fewer than five missing teeth, annual dentist visits, daily tooth brushing and no gum disease had lower odds than others of having head and neck cancer. Wearing dentures was not related to cancer risk, according to the results published in the Annals of Oncology.
“In my view, the findings are not new, but this does seem to be the largest and most comprehensive epidemiologic study to link poor oral hygiene to head and neck cancers,” said Dr. W. Jarrard Goodwin, Chief Medical Officer of the Sylvester Comprehensive Cancer Center of the University of Miami Health System.
Head and neck cancers are causally related to smoking and smokers have poor oral hygiene, so the cancer could be caused by the smoking rather than the lack of dentist appointments, he told Reuters Health by email. This study accounted for alcohol and tobacco exposure but not for diet, said Goodwin, who was not involved in the research.
“The indicators of oral hygiene/health that we studied are all somehow connected with chronic irritation to the head and neck,” Hashim said. “They are indicative of tooth wear, mechanical trauma, and general health maintenance.”
Most of the people in this study came from North America and Latin America, which may not apply to the global population, she said. Almost half of individuals had never or seldom been to a dentist.
“Very few individuals (11 percent) did not brush their teeth at least once per day,” Hashim added. “These are common grooming habits that take very little time in the long-run and certainly couldn't hurt, whether one is at increased risk for head and neck cancer or not,” she said.
“The positive note is that better oral hygiene and health practices could be started at any time,” she said.