Fluoride is a substance that naturally occurs in some water sources. It is derived from fluorine, the thirteenth most common element on earth, and is known to help prevent dental caries.
Fluoride works mainly by slowing down the process of demineralisation, whereby the enamel loses calcium and phosphate when exposed to acid following ingestion of food and drinks which contain sugars. It also helps to “heal” (remineralise) surfaces which show early signs of calcium or phosphate loss, such as an opaque appearance. Most benefit is obtained if a low level of fluoride is constantly maintained in the mouth throughout the day.
Fluoride delivered directly (or topically) to the tooth surfaces by toothpastes and rinses help to maintain fluoride levels in the mouth and provide added benefit to the fluoride delivered systemically via water fluoridation. Introduced in the mid- 1970s, fluoride toothpastes now account for over 95% of the toothpaste sales in this country. The sale of mouthrinses, many of which contain fluoride, has also increased considerably since the mid-1980s.
In Ireland, an estimated 70% of the population reside in communities served with water supplies containing a regulated amount of fluoride. The permissible range of fluoride in drinking water in Ireland is presently set at 0.6–0.8 parts per million (Health (Fluoridation of Water Supplies) Act 1960, (S.I. No. 42 of 2007)). This level of fluoride in drinking water is deemed optimal for the oral health of all age groups, including infants.
The dramatic improvement seen in the oral health of Ireland since the introduction of water fluoridation in the mid-1960s – particularly among children and young adults with lifetime exposure to water fluoridation (labelled “Full Fl” in charts) – has been mainly attributed to the caries-preventive effect of fluorides in water and in toothpaste.
The main advantage of water fluoridation is that its caries reducing effects are available to everybody on the fluoridated water supply and is considered safe even for infant use. Bottled drinking waters contain highly variable amounts of fluoride depending on their source. While it is legally permissible for bottled natural mineral waters to contain up to 5 mg/l of fluoride, when fluoride concentration exceeds 1.5 mg/l the warning “contains more than 1.5 mg/l of fluoride: not suitable for regular consumption by infants and children under 7 years of age” must be clearly carried on the bottle label (Commission Directive 2003/40/EC).
There are no known side effects of water fluoridation at the optimal level, other than dental fluorosis. Dental fluorosis is mainly a cosmetic condition, commonly characterised by fine white lines or white patches on the teeth. The risk of developing dental fluorosis is linked to the ingestion of excess fluoride during enamel formation (amelogenesis) of the permanent teeth in childhood. International research indicates that the early use of fluoride toothpastes in young children can lead to the development of fluorosis in permanent teeth.
In Ireland, dental fluorosis remains at a very mild to mild level as measured by the Dean’s Index. However, the increase in the prevalence of dental fluorosis when levels of water fluoridation had remained constant (at 0.8–1.0 ppm between 1964 and 2007) suggests that young children are swallowing excess fluoride from toothpaste. As a result of this finding, in 2007 the permitted level of fluoride in water was lowered from 0.8–1.0 ppm to 0.6–0.8 ppm as a means of reducing the total intake of fluoride among young children. Recommendations on the appropriate use of fluoride toothpaste in young Irish children issued by the former Expert Body on Fluorides and Health (2004-2022) advised that children aged 2–7 years should use only a small pea-sized amount of fluoride toothpaste 1,000–1,500 ppm and be supervised by an adult when toothbrushing; children under 2 years of age should not use toothpaste except on professional advice.
Fluoride toothpastes are an important source of additional fluoride and should be used twice a day to help maintain a constant level of fluoride in the mouth. Daily fluoride mouthrinses are particularly useful for people who are prone to high levels of decay and also for people wearing orthodontic braces; fortnightly fluoride mouthrinse programmes are used in a number of schools in non-fluoridated areas. It is advisable that fluoride mouthrinsing be carried out at a different time from fluoride toothbrushing to maximise the added benefits from these topical fluorides. Fluoride varnishes and gels are alternative forms of topical fluorides that require application by a dentist or dental hygienist.
Despite the widespread availability of fluoride toothpastes, the most recent national oral health surveys show that only 58% of Irish children brush their teeth at least twice a day as recommended and that older people (aged 65+) in particular have poor oral hygiene habits. Only 52% of older people who have natural teeth (i.e., are not toothless) brush their teeth at least twice a day and 4.5% never brush.
In Ireland, dental fluorosis remains at the very mild to mild level as measured by the Dean’s Index. However, the increase in the prevalence of dental fluorosis when levels of water fluoridation had remained constant (at 0.8–1.0 ppm between 1964 and 2007) suggests that young children are swallowing excess fluoride from toothpaste. As a result of this finding, in 2007 the permitted level of fluoride in water was lowered from 0.8–1.0 ppm to 0.6–0.8 ppm as a means of reducing the total intake of fluoride among young children.
Recommendations on the appropriate use of fluoride toothpaste in young Irish children issued by the former Expert Body on Fluorides and Health advised that children aged 2–7 years should use only a small pea-sized amount of fluoride toothpaste 1,000–1,500 ppm and be supervised by an adult when toothbrushing; children under 2 years of age should not use toothpaste except on professional advice.
The former Irish Expert Body on Fluorides and Health advised:
From 0 until 2 years of age:
- Start to clean a baby’s teeth as soon as the first tooth appears.
- Brush a baby’s teeth with a soft toothbrush and water only
- Do not use toothpaste. (Professional advice on the use of fluoride toothpaste should be considered when a child below 2 years of age is thought to be at high risk of developing dental decay (e.g. children with special needs).
From 2 until 7 years of age:
- Use a small pea-sized amount of fluoride toothpaste 1,000–1,500 ppm. (Paediatric toothpastes with low concentrations of fluoride (e.g., 500 ppm) require further research before their use can be recommended.)
- Supervise brushing twice a day, in the morning and at night just before bedtime.
- A child under seven years needs help from an adult when brushing teeth.
- A child should never eat or swallow toothpaste.
- Clean the teeth thoroughly twice every day with fluoride toothpaste.
Water Fluoridation and the appropriate use of fluorides play a major part in public health policy in Ireland in the prevention and management of tooth decay. Fluoridation began in Ireland in 1964 on foot of the Health (Fluoridation of Water Supplies) Act 1960. Currently, approximately 68.5% of the population receives fluoridated public water supplies.
Water fluoridation is one of the most widely studied public health policy initiatives in the world, with approximately 350 million people in some 60 countries globally residing in areas served by optimally fluoridated water supplies.
At the Sixtieth World Health Assembly (WHA60.17, Agenda item 12.9 23) in May 2007, on oral health: an action plan for promotion and integrated disease prevention, supported water fluoridation as a central strategy in oral health promotion. It explicitly recommended that "for those countries without access to optimal levels of fluoride, and which have not yet established systematic fluoridation programmes, to consider the development and implementation of fluoridation programmes, giving priority to equitable strategies such as the automatic administration of fluoride, for example, in drinking-water, salt or milk, and to the provision of affordable fluoride toothpaste;" (World Health Organisation 2007).
The effectiveness of water fluoridation in preventing tooth decay continues to be endorsed by a comprehensive range of authoritative international bodies including the World Health Organization, the Center for Disease Control and Prevention of the United States Public Health Service , the United States Surgeon General, the Federation Dentaire Internationale/ World Dental Federation and the International Association for Dental Research.