Public Health England (PHE) has today published a report which says adding the chemical to tap water will provide “significant benefits”.
The Government body's report says youngsters living in areas where fluoridation schemes are in place are less likely to have tooth decay than those in other regions.
The saga over whether fluoride should be added to the water of 200,000 homes in Southampton, Totton, Eastleigh, Netley and Rownhams has rumbled on since the South Central Strategic Health Authority (SHA) were given the go-ahead in 2009.
Campaigners have argued that no public consultation was carried out about introducing the scheme in Hampshire, and they also say it could lead to health problems and reduced IQs if introduced.
PHE took over the responsibility for implementing fluoridation after the SHA was scrapped last year, and the organisation has insisted the measure is “safe and effective”.
The organisation is currently locked in a legal dispute with Southampton City Council and Hampshire County Council, who believe the scheme does not exist due to a failure to hand over key documents between the SHA and PHE.
Both councils want a public referendum on fluoridation.
The authors of the PHE report, experts measured the dental health of five-year-olds with baby teeth and 12-year-olds with adult teeth from fluoridated and non-fluoridated areas.
They said that on average 15 per cent fewer five-year-olds have tooth decay that needed intervention in fluoridated areas.
And when deprivation and ethnicity - both important factors for dental health - are taken into account this figure rises to 28 per cent fewer cases of tooth decay.
Meanwhile there are 11 per cent fewer 12-year-olds with tooth decay in fluoridated areas compared to non-fluoridated areas.
This figure rose to 21 per cent when deprivation and ethnicity were taken into account, the authors said.
And in areas which participate in the water adjustment scheme there are 45 per cent fewer hospital admissions for tooth decay among children aged one to four.
The research compared rates of the effect on fluoridated Newcastle and non-fluoridated Manchester.
They found that the number of 12 year old children in Newcastle with moderate dental fluorosis was around 1% compared to 0.2% in Manchester.
But the authors said the overall dental benefit of the schemes were ''important''.
''Dental caries (tooth decay) is a significant public health problem in England,'' the report states.
''Sizeable inequalities in the incidence of caries exist between affluent and deprived communities, and it is a common cause of hospital admissions in children.''
Professor John Newton, chief knowledge officer at PHE, said: ''There is a good deal of speculation about water fluoridation schemes. This report provides new data which is direct evidence of the safety and efficacy of water fluoridation in England.
''There is no evidence of any effect on general health in fluoridated areas compared to non-fluoridated areas. There are important benefits in terms of dental health - it does look as if there are really significant benefits in those areas that have water fluoridation schemes.
''We will use this report as a basis for discussions with local authorities on the scope and content of further reports and on the role of fluoridation as a public health measure.''
Sue Gregory, director of dental public health at PHE, added: ''These findings highlight the important contribution that water fluoridation makes to children's dental health and general well-being.
''It is notable that the benefits of this public health measure appear to be greatest for children living in the most deprived areas of the country.
''This is significant for reducing the large differences we see in dental health between deprived and more affluent areas of the country.''