MANCHESTER — A key segment of the Manchester population saw no significant reduction in tooth decay over the first four years of fluoridation, and only experienced significant drops in tooth decay after the city launched a program to seal their teeth, according to Manchester Health Department data.
A top city health official cautioned against drawing too many conclusions from the data. The data tracked 12 years of tooth decay in second- and third-grade students from inner-city schools.
“It is not unexpected to see the untreated decay levels remain level or increase slightly shortly after water fluoridation,” said Anna J. Thomas, deputy public health director for the city. “In some cases, the decay may have been present long before community drinking water fluoridation began.”
But an anti-fluoridation group, contacted by the New Hampshire Union Leader, said the results look good for the sealant program, but not fluoridation.
“Since no benefit shows up following fluoridation for at least four years, I believe this shows that fluoridation in Manchester did not reduce decay in a detectable manner,” said Chris Neurath, research director for American Environmental Health Studies Project, which follows topics such as environmental injustice, fluoridation and sustainability.
Manchester Water Works started fluoridating the region’s water supply in December 2000, a year after the city voted in favor of fluoridation.
Manchester health officials have tracked decay of children in Title 1 schools as part of the city’s school-based sealant program.
Piloted in the 2004 school year and expanded the following year, the program is available throughout the city’s elementary and middle schools. It provides sealants free of charge to families that cannot afford them.
The data show a slight increase in untreated decay in the first two years of fluoridation — the 2001 and 2002 school years — and a slight decrease after that. A similar track is shown in decay that is treated.
But both measures start to drop faster in the 2004-2005 school year, when the sealant program kicked into high gear.
Thomas, and even Neurath, said the data should be interpreted cautiously. Thomas notes that the sample only involves children in Title 1 schools. Neurath also said increases in private dentist visits and the implementation of the Full Service Manchester School Dental Program could have impacted the results.
But both are eager to advocate for their side.
Endorsed by U.S. Surgeons General and the Centers for Disease Control, fluoridation provides teeth with frequent contact of low levels of fluoride throughout the day, Thomas said. The fluoride helps to re-mineralize tooth surfaces harmed by acid generated by sugar and refined carbohydrates, she said.
Significant population shifts, including rising poverty and increased diversity, may explain the slight rise in decay in the early 2000s, she said.
Thomas said both sealants and fluoridation are evidence-based strategies recommended by the CDC and the Community Preventive Services Task Force. And she said all community members receive the benefits of fluoridation.
“One’s income level or ability to receive routine dental care is not a barrier to receiving the health benefits,” she said.
Neurath said that the idea has been discredited the fluoride ingestion helps developing teeth. But fluoride advocates still maintain its effectiveness through exposure to the surface of enamel, he noted. But the Manchester data don’t support that, he said.
“Any topical benefit should show up almost immediately,” he said. “For this data, within a year or two.”
He said the sealant program seems to be responsible for a 15-percentage point reduction in the history of decay over five years.
“While by no means eliminating decay, this is a substantial enough benefit that it is probably a worthwhile public health program,” he said. “In contrast, since fluoridation does not appear to have reduced decay at all, it is all money ‘down the drain.’”