To ask Her Majesty’s Government, further to the Written Answer by Earl Howe on 28 October (WA 212–3), whether in the matter of potential harm from water fluoridation Public Health England distinguish between absence of evidence and evidence of absence.
To ask Her Majesty’s Government, further to the Written Answer by Earl Howe on 28 October (WA 212–3), why Public Health England, in comparing findings by McGrady et al in their BMC Public Health 2012 paper and by the NHS Centre for Reviews and Dissemination at the University of York in their 2000 report on water fluoridation, did not cite the respective figures in fluoridated populations of 55% and 48% for all dental fluorosis in place of figures for the categories of “severe” and “moderate” fluorosis which the York report did not address.
To ask Her Majesty’s Government, further to the Written Answer by Earl Howe on 28 October (WA 212–3), whether they regard the quality of evidence obtained by adding the cross-sectional study by McGrady et al to the five earlier studies cited in the discussion section of his paper and graded by the York report at level C or lower as adequate to show that water fluoridation reduces the social gradient in dental caries.
To ask Her Majesty’s Government, further to the Written Answer by Earl Howe on 28 October (WA 212–3), how accurate they consider the examination of the maxillary central incisors of 11 to 13 year-olds, as conducted by McGrady et al, to be as an indicator of the extent of dental fluorosis in a fluoridated population.
Water fluoridation schemes have operated for nearly 50 years in England and over 50 years internationally. In that time no evidence has arisen demonstrating that there is harm to general health from these schemes. Furthermore there are communities in England who have consumed fluoride in their water supply for generations at levels close those achieved by water fluoridation schemes. It is reasonable to judge that, after the passage of so many years of public health surveillance, if there was any harm to general health from water fluoridation then this would be apparent.
The authors of the York review of water fluoridation have stated that they found a benefit in the form of reduction in caries, balanced against an increase in fluorosis and that no clear evidence of other potential negative effects was found. In 2002, the Medical Research Council made recommendations regarding surveillance and research priorities. The National Institute for Health Research welcomes funding applications for research into any aspect of human health, including water fluoridation. These applications are subject to peer review and judged in open competition, with awards being made on the basis of the scientific quality of the proposals made. Any new evidence emerging regarding water fluoridation will be assessed by Public Health England (PHE). PHE is currently working towards publishing a first report on the health effects of fluoridation by the end of March 2014, as required by legislation. This will be a publicly available document. Further reports will follow within four-yearly time periods in accordance with the timetable prescribed in legislation.
Given the degree of scrutiny that has been applied to the links between water fluoridation and general health, the government is satisfied that water fluoridation is a safe and effective public health measure. What is very apparent is the harm caused by dental caries which is still a common cause of children to be admitted to hospital and affects those children from deprived communities the most.
The study by McGrady et al used novel technologies and photographing teeth in order to facilitate a highly standardised and reliable assessment of mottling (fluorosis), reducing potential examiner bias—a key recommendation of the York Review. Fluorosis is primarily a cosmetic issue affecting the appearance of the teeth and therefore, when attempting to assess whether there is a greater level of mottling in populations which may be caused by fluorosis, it is useful to distinguish mottling which is likely to be of aesthetic concern.
Whilst this study by McGrady et al is a cross-sectional study, it is the largest and most recent study to be undertaken on a domestic population since the York Review and addresses methodological concerns raised by that review. The study supports previous work and adds to the evidence base, providing further assurance that water fluoridation reduces oral health inequalities. The aforementioned report by PHE will also review the available information on tooth decay levels in fluoridated communities.
The maxillary central incisors are usually the most visible teeth in the mouth when smiling and speaking and will therefore contribute the most to the aesthetic appearance of the dentition. The use of maxillary central incisors in this study was partly to facilitate the use of a standardised photographic methodology and partly to reflect that the appearance of the two largest upper front teeth will be a key part of an individual’s perception of the appearance of their dentition as a whole. Fluoride absorption during tooth development will potentially affect all developing teeth so examination of the maxillary central incisors should provide a good representation of the teeth as a whole. Furthermore, the enamel of these teeth will be fully visible at the age of 11. Therefore this research methodology appears appropriate for the purpose of providing an accurate estimate of clinical fluorosis levels in a population and has advantages over visual examination and scoring as factors such as differences in incident light can affect the appearance of teeth quite markedly.