A South Island wide study of dental decay in 12-year-olds is being used by anti-fluoride campaigners to push the case of keeping fluoride out of Ashburton’s community water supply.

The information was presented at a meeting on Thursday night, called by anti-fluoride campaigners, and is part of a package of data being used to ensure all voters are fully informed before the district’s fluoride referendum begins on February 16.

Ministry of Health statistics for decay in 12-year-old children for 2004 show the benefits of fluoridation of community water supplies are proven in the North Island, but in the South Island, there appears to be little, if any benefit.

The data divides regions into fluoridated and non-fluoridated water groups and it also indicates the percentage of the population deemed to be of low socio-economic status.

Nelson Marlborough is fully non-fluoridated and has a low socio economic status of 11 per cent. It’s 12-year-olds have just 1.25 decayed, missing or filled teeth at age 12.

In the fluoridated parts of Canterbury, 12-year-olds have 2.45 decayed, missing or filled teeth, while unfluoridated Canterbury 12-year-olds have 1.58.

Canterbury has just 4 per cent of its water supplies fluoridated and has 15 per cent of its population listed as low socio-economic.

Otago has the highest percentage of its population on fluoridated water supplies, 47 per cent, and the lowest number of people listed as low socio-economic. In its 12-year-old population those on fluoridated water have 1.65 decayed, missing or filled death, and on non-fluoridated water 1.94.

Southland ranks at the bottom of the table, with 41 per cent on fluoridated water, 24 per cent listed as low socio economic status. On fluoridated water 12-year-olds have 2.03 decayed, missing or filled teeth and those without fluoridation, 2.11.

The data also showed the changes in decay rates for Timaru 12-year-olds, an area where fluoride was removed from the water supply in 1984. At that time 12-year-olds were 15.04 per cent caries free, by 1989 they were 31.05 per cent caries free and by 2004, 41.98 per cent.

Timaru’s experience is being used as a support case for keeping fluoride out of Ashburton’s community water supply.

People connected to the town’s water supply will be able to cast a vote for or against fluoride when a referendum is held from February 16–March 10.

Voting papers will be posted by the Ashburton District Council and must be returned by noon on the final day. The council expects to have the result of the binding referendum on fluoride known on March 10.