Fluoride should be added to water supplies across England to stem the increasing number of children being admitted to hospital with tooth decay, dental surgeons say.

Almost 26,000 such children between five and nine were admitted in 2013-14, making it the number one reason for admission in the age group and representing a 14% rise in three years.

About 10% of water supplies in England have fluoride content, either naturally or artificially, at the optimum level for dental health. But in a report on the state of children’s oral health, published on Tuesday, the Royal College of Surgeons’ (RCS) faculty of dental surgery says that is not good enough.

The faculty’s dean, Prof Nigel Hunt, said: “One of the biggest problems that comes out in the document is the inequality in terms of oral health up and down the country and providing water fluoridation is one way of overcoming that. We know it’s of proven benefit.”

He cited a 2014 report by Public Health England that found 45% fewer children aged one to four were admitted to hospital for tooth decay in fluoridation areas.

Almost a third of five-year-olds are suffering from tooth decay, linked to consumption of sugary or acidic food and drink, around 90% of which is deemed to be preventable. There are significant regional variations with over 60% more cases among five-year-olds in the north-west of England than in the south-east. In Leicester, a third of three-year-olds have tooth decay, compared to just 2% in south Gloucestershire.

Despite also winning the support of the British Dental Association, adding flouride at one part per million, in an effort to reduce tooth decay, has proved a controversial issue.

In Hampshire, plans to add fluoride to the water supply were scrapped in the face of opposition from the local authorities and the public. Opponents claim that it can be unsafe and forcible medication. But the PHE report that Hunt referred to examined the comparative rates of hip fractures, kidney stones, cancers, Down’s syndrome births and all-cause mortality and found no difference, concluding that there was “no evidence of harm to health in fluoridated areas”.

As well as fluoridation in water, the RCS wants the government to invest in a national oral health programme, similar to Childsmile in Scotland. The £1.8m Scottish scheme, which includes supervised toothbrushing for children in primary school and nursery in deprived areas has saved more than £6m in dental costs between 2001 and 2010. The RCS, which represents around 4,500 specialist dentists, also wants awareness raised on the impact of sugar on tooth decay and for the government to ensure that all children with advanced tooth decay have timely access to specialist paediatric services.

“We are talking about a relatively small amount of money that will provide life-long benefit,” said Hunt. “If oral health isn’t tackled as a child, there is growing evidence there will be problems later in life.”

Chief dental officer Barry Cockcroft said dental health had improved dramatically over the past 10 years “We strongly encourage parents to take their children for regular dental check-ups - so dentists can promote healthy mouths and prevent decay before it happens,” he said.“Tooth decay is almost completely preventable through a balanced diet and good oral hygiene.”

A spokesperson for the National Pure Water Association said: “The Royal College’s otherwise good report is spoilt by its flawed recommendation to increase the extent of fluoridation in the UK.

“There is good evidence to support oral health initiatives like Scotland’s Childsmile programme, which costs less than fluoridation in England and covers more people. After nearly 70 years of fluoridation, there is not one high-quality scientific study (an individual, randomised, controlled trial) that shows fluoridation to be effective or safe.”