Using water with fluoride significantly reduces tooth decay, even if that use didn't start until adulthood, a new study finds.
The study examined dental records of 3,779 older teens and adults who had spent various amounts of time living in communities with fluoridated water supplies. "We found there are protective effects for adults and, equally important, that the protection occurs even if those adults didn't have access to fluoridated water when they were children," said Gary Slade, who directs the University of North Carolina-Chapel Hill School of Dentistry's oral epidemiology Ph.D. program.
Many people think of tooth decay as a childhood issue, Slade said, but adults are equally vulnerable. Today's adults with good dental health may have long years of living with fluoridated water supplies to thank, he said.
"It's an escalating benefit," Slade said. "The more prolonged your exposure to drinking fluoridated water, the better."
Fluoride is a mineral occurring naturally in the earth that strengthens tooth enamel. It is often added to toothpaste and dental rinses.
The Campaign for Dental Health, a coalition of dental and health groups, said tooth loss among people ages 65 and older has dropped by 21 percent since 1961, when fluoridation was widely introduced.
Slade was working in Australia when he began the study in the late 1990s. He and other researchers from the University of Adelaide traced dental histories of their subjects -- all Australians ages 15 and older -- back to 1963. Australia had little fluoridation in the early 1960s, but by 1980 two-thirds of the country had fluoridated water supplies. Results showed that adults spending more than 75 percent of their lives in communities with fluoridated water had about 30 percent less tooth decay than those living for the same duration in areas without treated water.
The research findings were published last week in the online Journal of Dental Research. Fluoride has been used in public water supplies for more than 60 years, reports the federal Centers for Disease Control, which lists water fluoridation as one of the 10 greatest public health achievements of the 20th century.