Parts of the country with fluoridation schemes include Cumbria, Cheshire, Tyneside and Northumbria
Just over 6.1 million people in the UK receive water with a fluoride content, whether naturally occurring or added.
This means that about 10% of the total population is supplied with optimally fluoridated water.
The number of people whose water supplies contain naturally occurring fluoride at the optimum level (around one part of fluoride per million parts of water) is estimated at around 330,000, including those living in Hartlepool and Easington in the north east of England, Uttoxeter in Staffordshire and parts of north Hampshire and south Berkshire.
Around 5.8 million people in different parts of England are supplied with artificially fluoridated water. In these communities, the naturally occurring fluoride is too low to protect teeth from decay and has therefore been supplemented at the water treatment works to bring it up to the 1 ppm concentration.
Parts of the country with fluoridation schemes include Cumbria, Cheshire, Tyneside, Northumbria, Durham, Humberside, Lincolnshire, Nottinghamshire, Derbyshire, the West Midlands and Bedfordshire.
Some areas receive water with naturally occurring levels of fluoride that is below the optimum for oral health but can afford some degree of protection against tooth decay. However, in many instances the level of fluoride varies over time.
Some local fluoridation
Around 120,000 people live in areas of west Cumbria covered by legal agreements for the supply of artificially fluoridated water.
Communities covered by those agreements include Workington, Maryport, Aspatria, Wigton and Cockermouth in the Allerdale Borough Council area and the communities of Whitehaven, Egremont and Ravenglass in the Copeland Borough Council area.
Around 137,000 people are supplied with artificially fluoridated water in Cheshire.
Fluoridated communities include Crewe, Nantwich, Alsager, Bickerton, Bulkeley, Burland, Wrenbury, Egerton Green, Faddiley, Beeston, Broxton, Handley, Huxley, Malpas and Tarporley.
Around 643,000 people are supplied with artificially fluoridated water in and around Tyneside.
Fluoridated communities include Newcastle upon Tyne, Gateshead, Wallsend, North Shields, Tynemouth and Whitley Bay.
About 43,000 people are supplied with artificially fluoridated water in Derbyshire.
Fluoridated communities include parts of Bolsover District bordering Nottinghamshire, and parts of South Derbyshire District bordering Staffordshire
Around the world
Estimates of fluoridation coverageated show that over 204 million US residents are supplied with naturally or artificially fluoridated water at the optimum concentration for oral health. This represents 74% of the US population whose homes are connected to public water supply systems.
Of the 204 million people receiving optimally fluoridated water, 194 million are served by artificial water fluoridation schemes, an increase of around 8.5 million people since 2008, 20.5 million since 2006 and 32.5 million since 2002.
Brazil is the second most extensively fluoridated country in the world after the United States. As at 2008, the number of Brazilians benefiting from artificially fluoridated water was 73.2 million (41% ofthe population) in some 3,350 different communities.
Around 11 million people in Chile, an increase of around 6.6 million since 2003.
This makes Chile the second most extensively fluoridated country in South America after Brazil. Major Chilean cities with fluoridation schemes include Santiago, the capital, and Valparaiso.