Water Fluoridation in the Xxxxxxxx of England Key Stakeholders Briefing July 2008
Overview & scrutiny committee – Water Fluoridation Briefing August 2008
Introduction
Changes to the Water Act, enacted in 2003, have given Primary Care Trusts (PCTs) in the North West the opportunity to consider the possibility of water fluoridation as a method of reducing levels of dental caries (tooth decay) in the population.
Information has now been gathered for PCTs to enable them to decide whether they wish to request the North West Strategic Health Authority (SHA) to explore the possibility of water fluoridation. PCTs across the North West will now be taking the opportunity to engage with their key stakeholders to discuss this issue. At this stage this engagement will involve providing important updates on the decision making process involving PCTs and the SHA in the North West; sharing evidence; and seeking their views on the process by which each PCT will make a decision on whether to ask the SHA to explore the possibility of fluoridation.
The purpose of this paper is to summarise the circumstances relating to dental caries levels in the locality; describe the potential options to address these; to explain the legislative framework relating to water fluoridation; review contemporary guidance issued by the Department of Health; and to outline the decision making process involving each PCT in the North West. It is intended to support discussions to be held during the key stakeholder engagement phase.
Dental caries in Blackpool
Dental caries is a common, preventable condition. It is a disease of the teeth in which micro-organisms convert sugar in the mouth to acid. This acid then erodes the teeth.
Average levels of caries prevalence (the number of individuals with one or more teeth affected by decay) and severity (the numbers of teeth affected by dental caries) in children in Blackpool as a whole are high compared with other areas in the North West, and fail to meet improvement targets set for 2003
Fig 1
The proportion of children in Blackpool with dental decay at five years of age, measured in 2005/2006 is higher than the statistic for the North West and for England. This is illustrated in Figure Two.
Fig 2
The consequences of suffering from caries for individuals and their families include severe pain, abscess formation, sleep loss for patients and parents or carers and behavioural problems. There may also be a need for extractions under general anaesthesia with its associated, potentially life-threatening risks. In 2005/2006 357 child residents of Blackpool were admitted to hospital for the extraction of teeth. Further, suffering from caries in childhood is the strongest predictor for suffering from caries in adulthood.
There are no local adult dental caries prevalence data available for Blackpool PCT. However, national data collected in the most recent UK Adult Dental Health Survey in 1998 suggest that, at local level there are likely to have been decreases in the levels of caries in adults since the 1970s. Notwithstanding the general reduction in caries prevalence across the country, marked regional differences were noted. For example, almost two-thirds (65%) of dentate adults in the North had at least one decayed or unsound tooth, compared with just over half of those living in the Midlands (52%) and the South (51%). This, added to the high levels of dental caries in children will mean that dental caries and its consequences will continue to affect a substantial proportion of the local population for the foreseeable future, unless additional preventive interventions are introduced.
1
Version 4 26-08-08
Preventing caries – the options
Fluoride has been the cornerstone of caries-preventive strategies for more than five decades. Fluoride acts principally topically. It prevents caries by acting in two main ways:
1. It reduces the loss of mineral from the tooth surface when it is under acid attack.
2. It repairs the damage caused by the caries process. As part of the repair process fluoride and makes the tooth more resistant.
There is a suggestion that fluoride also kills the bacteria that cause caries, but there is only weak evidence for this. It is important to note that fluoride has a caries-preventive effect on both children’s and adult’s teeth
There are a number of ways in which fluoride can be used to have a caries preventive effect. It may be present naturally, or can be added to drinking water, fluoride-containing salt, milk, toothpastes, mouth rinses, gels, varnishes and slow release devices are the modalities most used at present, either alone or in combination, to provide a predominantly topical caries preventive effect.
In addition to fluoride there are two other interventions which do not deliver fluoride that are commonly used in attempts to prevent caries. The first of these is the use of fissure sealants, which acts by physically protecting some vulnerable surfaces of teeth i.e. pits and fissures. The second is dental health education and promotion, which is intended to increase knowledge of caries-risk behaviour and attempts to improve dental health related behaviour.
As this paper principally relates to water fluoridation a summary of the evidence of the benefits and potential harms is given below. A more concise summary of each alternative intervention, the evidence of its effectiveness, and limitations is given below. A more comprehensive analysis of caries-preventive interventions can be found in a report prepared by the Office for Public Management in June 2008 which is discussed below. This has been the principal source of data for this section.
Water fluoridation
Water fluoridation is the process of artificially topping up the natural fluoride in water to the level at which it can help to reduce tooth decay.
Gathering Evidence
The Department of Health commissioned York University to review the evidence of the safety and efficacy of fluoridation of drinking water (York Review). This was published in 2000. Details of the York Review objectives and findings can be found in Appendix One. When undertaking the review York Reviewers found little high quality research of relevance to their research questions. Having considered the findings of the York Review, the Government asked the Medical Research Council (MRC) to establish ways that the evidence for the benefits and disbenefits of fluoridation might be strengthened. The MRC reviewed the existing evidence, and considering the possibilities of adverse health effects, identified length of exposure may be relevant. The MRC acknowledged that whilst there had been over 40 years of exposure to artificially fluoridated water in Birmingham, other UK population groups had been exposed to naturally fluoridated water for considerably longer. To be confident that observations made on populations receiving naturally fluoridated water were applicable to the populations receiving artificially fluoridated water, on the recommendation of the MRC, the Department of Health commissioned a study into the bioavailability of fluoride in both artificially and naturally fluoridated water. This found no evidence of any differences between the absorption of fluoride ingested in artificially fluoridated drinking water and in drinking water in which fluoride was present naturally. Since this time a further review of evidence, commissioned by the Australian Government’s National Health and Research Council (Australian Review) has been undertaken which was published in December 2007.
Evidence of potential benefit
The York Reviewers were able to confirm that the best available evidence suggested that fluoridation of drinking water supplies does reduce caries prevalence and severity. The more recent Australian Review has not challenged this. It is noted that the review stresses that the degree to which caries is reduced is not definitive and reports a wide range of effectiveness both in terms of prevalence and severity. Available evidence also suggests that the more deprived an area, the greater the benefit derived from fluoridation on caries severity, whether it be natural or artificial.
The York Reviewers also found that caries prevalence rises following withdrawal of water fluoridation. These findings are supported by evidence from the North West, where there are three water treatment works that provide fluoridated water to the populations in their catchment areas. Hurleston supplies Nantwich and part of Crewe, whilst the two works in Cumbria together supply an area of West Cumbria which includes Workington and Whitehaven. Unlike the Cumbria schemes, the Hurleston scheme has been running since its inception in 1991.
The child population resident in Cheshire that has received an uninterrupted supply of fluoridated water have a significantly lower prevalence of caries compared with the population that have not. This was demonstrated across all socioeconomic groups. This effect was however not mirrored in the Cumbria child population that had been supplied with an interrupted supply of fluoridated water.
Evidence of potential harms
Considering potential harms, the York Review highlighted the association between water fluoridation and dental fluorosis [1] and estimated that at a concentration of 1 part per million (ppm), the prevalence of aesthetically objectionable fluorosis was estimated at 12.5%. During early fluoridation trials, it was found that 1ppm in temperate climates such as the UK gave a balance between minimising the risk of dental fluorosis whilst also giving major reductions in tooth decay.
Overall, no clear association between water fluoridation and incidence or mortality of bone cancers, thyroid cancer or all cancers was found. The studies examining other possible negative effects provided insufficient evidence on any particular outcome to permit confident conclusions.
Fluoridated salt
The caries-preventive effectiveness of fluoridated salt has not been studied in the UK. Nevertheless, studies carried out in other parts of the world demonstrate significant improvements in caries prevalence and severity. Given the risks for individuals in promoting the use of fluoridated salt, its use is not a viable option for a community programme.
Fluoridated milk
The majority of the relevant evidence finds that milk fluoridation schemes do reduce caries, but this reduction is not definitive. A recent study, carried out in Liverpool has reported no significant benefits for primary dentition. The effectiveness of milk fluoridation schemes is heavily reliant on compliance at a number of levels.
Fluoride toothpaste
High quality evidence demonstrates that brushing with a suitable amount of an appropriate strength of fluoride toothpaste reduces caries in both the primary and permanent dentitions. The higher the fluoride concentration the better the effect. Caries prevention is also reliant on compliance. It is important that fluoride toothpaste is not ingested if fluorosis is to be avoided.
Fluoride varnish
Fluoride varnish is professionally applied. High quality evidence shows that it can substantially reduce caries in the primary and permanent dentitions as measured by both prevalence and severity. The effective use of fluoride varnishes requires compliance and regular attendance at dental services or the provision of a community-based scheme.
Fluoride tablets or drops
The use of fluoride tablets or drops can have a caries-preventive effect. They are not recommended for use in community schemes for a number of reasons including consent and compliance issues.
Fluoride mouth rinses
Fluoride mouth rinses have been shown to be an effective caries-preventive measure, and are recommended for use in the UK as part of an individual caries-preventive regime for those at high risk of developing caries. Their effectiveness is limited by compliance factors.
Fluoride gels and slow release devices
The use of fluoride gels and slow release devices (SRGs) and is targeted at high risk individuals. Fluoride gels are effective at reducing caries and SRGs can be more effective than water fluoridation, although this is due to the fact that they are targeted at high risk individuals rather than the general population. As these interventions are applied by a dental professional, they require regular attendance at dental services.
Fissure sealants
High quality evidence has shown that that resin based fissure sealants are effective in preventing caries. As fissure sealants are applied by a dental professional, they require regular attendance at dental services.
Dental health education and promotion
There appears to be very little evidence on the caries-preventive effectiveness of dental health education and promotion. High quality evidence has shown that dental health education leads to improved knowledge levels and temporary improvements in oral health related behaviours.
Note
There are a number of interventions which can be implemented as part of a caries preventive regime for at both individual and population level. Some of these are already being used in schemes. This consideration of water fluoridation should be as an addition to these measures. It is noted that water fluoridation is the only community-based available option not requiring compliance at individual level.
1
Version 4 26-08-08
Considering Water fluoridation
PCTs are responsible for assessing the oral health needs of their population and for commissioning services or interventions required to address identified needs. In discharging their duty to improve oral health of their population, PCTs have been encouraged by the Chief Dental Officer to consider the option of fluoridating their water supplies.
Legislative framework
Arrangements for all the existing fluoridation schemes in the UK were made before 1985. In 1985 the ‘The Water (Fluoridation) Act 1985’ was passed and subsequently incorporated into ‘Water Industry Act 1991’. Part of this Act stated that, ‘Where a District Health Authority have applied in writing to a water undertaker for the water supplied within an area specified in the application to be fluoridated, that undertaker may, while the application remains in force, increase the fluoride content of the water supplied by the undertaker within that area’. Despite the policy intentions of successive UK Governments, because water undertakers did not feel equipped to make decisions on what they considered to be a public health issue, no new schemes were introduced under this legislation. This prompted amendments to the Water Industries Act 1991.
The Water Act 2003 amended Water Industries Act 1991 which now includes an obligation on water providers and reads as follows
“If requested in writing to do so by a relevant authority a water undertaker shall enter into arrangements with the relevant authority to increase the fluoride content in the water supplied by that undertaker to premises within the area specified in the arrangements”.