The survey found tooth decay among Southampton children at a ten-year low, as reported in yesterday’s Daily Echo.
The city council’s backing for the plan – affecting nearly 200,000 residents – in last year’s public consultation was seen as key to those in favour of the scheme.
Every other local authority – Hampshire, Eastleigh, New Forest and Test Valley councils – opposed the proposals.
Cllr Smith said: “The council was probably the most important consultee, and whatever we said or did was going to be taken very seriously.”
Every councillor had a free vote in November, and they backed fluoridation 26 to 18.
The report for the meeting claimed the city’s dental health was deteriorating and worse than regional and national averages.
Cllr Smith said the latest figures showing Southampton has lower levels of tooth decay than fluoridated Birmingham, are another nail in the coffin for the case for adding fluoride to the water.
“The main thrust was the poor state of dental health in Southampton, and that’s now shown not to be the case,” he said. “That, combined with the overwhelming public opposition and will of the people should be enough for the SHA to rethink their plans and abandon them.”
South Central Strategic Health Authority has said it remains committed to fluoridation.