It's a health debate that has raged for nearly 30 years - should water companies add fluoride to the water supply?
Campaigners for fluoridation say it is an essential tool against tooth decay, as it helps to strengthen children's teeth and therefore leads to fewer fillings.
However, opponents say 15 per cent of people in areas where it already occurs naturally or intentionally have mottled teeth, because of too much fluoride.
Some also accuse the Government of a 'Big Brother' attitude, imposing healthcare without choice.
The British Dental Association (BDA) has been at the forefront of the campaign to introduce selective fluoridation, backed by the British Medical Association and the British Fluoridation Society (BFS).
To give local health authorities the legal right to add fluoride in areas where they think it is required medically. To win over peers and MPs, who would have the ultimate decision.
Strategy and Plan
Although the issue has been debated for nearly three decades, the dentistry profession was still frustrated by a lack of legislation.
But the BDA saw an opportunity when Leigh MP Andy Burnham set down an early day motion calling for fluoridation in his area.
An amendment to the Water Bill followed. The issue would first be debated in the House of Lords, where the BDA's cause was taken up by Lord Hunt, former head of the Health Confederation
Campaign planning began in February. The BDA press team proposed sending mailshots, including a briefing on the benefits of fluoridation, to each peer. In July, the Lords voted by five to one to include the amendment.
'We were pleased, but we knew the Commons was going to be much harder,' said Tanner. 'MPs have constituents who need to be kept happy.'
The press team drew up a league table for each parliamentary constituency in England and Wales, showing levels of decaying teeth among five-year-olds, using red, amber and green to show the level of decay. The table was accompanied by a fact sheet on fluoridation and sent to each MP.
The next stage was to attend the major party conferences, and a fringe meeting on the issue was held at Labour's Bournemouth conference.
To coincide with the political lobbying, the BDA introduced 48,000 postcards featuring two six-year-olds, one with good teeth, the other with bad teeth, from two different areas - one with fluoride in the local supply and the other without - with the slogan 'spot the difference?'. BDA members were urged to send them to local MPs and distribute them in their surgeries to be posted.
Also, 13,000 cards were inserted into Public Health News and a further 2,000 distributed to the BFS.
In the run-up to last week's crucial vote, the press team sent out regular press releases updating the campaign. On the eve of the Commons vote, the press team pulled off a coup. Four former health secretaries - Alan Milburn, Ken Clarke, Frank Dobson and Norman - now Lord - Fowler - wrote to The Sunday Times backing selective fluoridation.
Measurement and Evaluation
Both the issue and the campaign were covered extensively over the past eight months. Print coverage included The Times, The Independent, The Daily Telegraph, the Daily Mail and the Daily Mirror. BBC and ITN - both nationally and locally - covered the story, as did Sky News, BBC online and trade press such as Dentistry and the British Dental Journal.
On 10 November, the debate reached a climax when the House of Commons voted to grant local health authorities sole charge on whether to add fluoride to water supplies, subject to local consultation.
In a free vote, two other amendments were voted down. The first would have banned adding fluoride to water supplies where it already occurs.
The second, giving powers of local consultation to councils rather than health authorities, was lost by 200 to 243 - paving the way for health authorities to add fluoride to local water supplies, subject to local consultation and need.
Dentistry reporter Julian English said the BDA ran a strong campaign.
'They were energetic and proactive. Lobbying MPs at conferences was a good idea. It was a relatively easy decision by the executive to back fluoride in water once the Government had given a free vote, but we'll have to wait and see whether the campaign transfers to other areas.'
Adam Bowen of the BBC's Politics Show added: 'The BDA had to fight a lot of scepticism in its campaign. At the end of the day, Parliament voted it through, so it has to be seen as a success. The big challenge now is how health authorities win local backing for it to happen.'