BASCD Survey report

The dental caries experience of 5-year-old children in Great Britain 1999/2000.

Surveys coordinated by the British Association for the Study of Community Dentistry in 1999/2000

N.B. Pitts(1), D.J. Evans(2) and Z J Nugent(3)

1 BASCD Dental Epidemiology Programme Scientific Coordinator, Dental Health Services Research Unit, University of Dundee, Dundee, UK;
2 BASCD Dental Epidemiology Programme Service Coordinator, Newcastle and North Tyneside Health Authority, Newcastle-upon-Tyne, UK;
3 Statistician, Dental Health Services Research Unit, University of Dundee, Dundee, UK

Correspondence to: Professor N B Pitts, Dental Health Services Research Unit, Dental School, Park Place, Dundee, Scotland, DD1 4HR.

Key Words: dental caries, dental epidemiology, caries prevalence, national surveys, oral health

Introduction:

This paper sets out the results of the most recent series of surveys, of 5-year-old children, conducted within the National Health Services (NHS) under the auspices of the British Association for the Study of Community Dentistry (BASCD) Dental Epidemiology Programme during 1999/2000. The programme seeks to monitor the dental health of children and contributes to the national monitoring of service provision and targets, while providing data locally to aid in service planning and the evaluation of local oral health strategy targets.

Methods:

The agreed BASCD criteria (Pitts et al, 1997) and conventions set out in the BASCD trainers' pack (Mitropoulos et al, 1992) were employed. Within each part of Great Britain and within each former English "region", a designated NHS epidemiology coordinator was responsible for the local delivery of the programme, assisted by a "regional" trainer who attends the biennial national training and calibration exercise. Representative samples were drawn from participating health authorities and boards according to the agreed BASCD guidelines (Pine et al, 1997).

Dental caries was diagnosed at the caries into dentine (d3) threshold using a visual method without radiography, fibre-optic transillumination, or compressed air. Since this excludes all enamel and precavitation lesions, it will produce lower estimates of caries experience than are found when enamel lesions can also be scored (d1) (Pitts and Fyffe, 1988), or when diagnostic aids are used. For brevity, dmft has been used in the main text to indicate the dentine threshold.

Results:

A total of 199440 five-year-old children from across Great Britain were examined, some 14% more than in the 1997/99 survey (Pitts & Evans, 1997). On average this represents 30% of the total population of this age group, although in the different areas there was a wide range in the size of samples chosen according to local needs and practices. Table 1 shows total populations and samples, results for dmft and its components, the percentage of children with dmft>0 and dt >0, and values for the care index percentage (ft/dmft x 100 per cent) for the current NHS regions in England and for every participating health district or board in the remainder of Britain.

The results demonstrated a wide variation in prevalence across Great Britain, with mean values for dmft for regions and countries ranging from 0.94 in the West Midlands to 2.55 in Scotland. The mean value for dmft across Great Britain was 1.57 (dt=1.14, mt=0.22, ft=0.21). The variation in mean disease levels within regions and countries was also marked.

Overall, the extremes for district/board mean dmft values ranged between 0.58 for Solihull and 3.51 for Greater Glagow, Scotland. The corresponding values for dt ranged from 0.38 in Solihull to 2.61 in Greater Glasgow, Scotland, while for mt they ranged from 0.05 in South Staffordshire to 0.68 in Greater Glasgow. Although a mean of 40% of 5-year-old children in Great Britain had evidence of dentinal caries experience (dmft>0), the regional / country means ranged between 30% (West Midlands) and 55% (Scotland).

The overall number of filled primary teeth remains very low (British mean ft=0.21). The British mean care index was 14% with a wide regional/country range from 8-20%. In individual districts and boards the range of care index was from 37% in North and East Hertfordshire to 6% in Wiltshire, Greater Glasgow and North Cheshire.

The geographical variation of caries experience is highlighted in map form in Figure 1. The lower levels of mean caries prevalence (dmft < 1.5) were towards the south and west of England, although London joins Northern and Yorkshire with mean values of 1.51-2.00, North West, Wales and Isle of Man had mean dmft levels between 2.01 and 2.50. Higher disease levels were seen in Scotland.

Figure 2 presents the mean dmft information as a bar chart; this shows a ranking of the regions and countries including the 95 % confidence intervals. This demonstrates once again that the lowest mean values for a regional office were found in the fluoridated West Midlands. The bar chart reveals that Britain can be seen as a continuum from "southern" areas with mean dmft values of between 1.0 and 1.4, Wales to London and the north, through Wales to the other extreme in Scotland. Jersey rivals the best districts of the south, while the Isle of Man fits in with its northern neighbours.

Figure 3 shows a comparison of the mean dmft results (and components) from 1999/2000 with those from the 1997/98 survey. Note that the rank ordering of areas has changed in the two year period, that the degrees of improvements vary, that values for London and North West have increasing slightly, while results for Eastern were virtually unchanged.

Figure 4 shows a similar presentation of the care index values for each region/territory for the 1999/2000 and 1997/98 surveys ordered according to mean dmft in 1999/2000. This reveals a wide variation in the pattern of change.

Discussion

The results of this year's surveys have been produced according to the current NHS boundaries in England. Results and detailed retrospective comparisons of summary information from earlier studies over a ten year period can be found in a supplement to Community Dental Health (Nugent & Pitts, 1997). District/board results are also available on the BASCD web-page and, in England, through the Public Health Common data set - Oral Health Indicators.

Although there is an increasing focus on "local" and regional variations in dental health, the bar chart in Figure 2 should not be seen, or used, as a simple "league table". Small differences between means which do not exceed the 95 % confidence intervals should not be given undue weight. When comparing these 1999/2000 results with those of earlier BASCD co-ordinated surveys of 5-year-old children conducted in 1997/98 (Pitts Evans and Nugent, op.cit.), 1995/96 (Pitts and Evans, op.cit.), 1993/94 (Pitts and Palmer, 1995), 1991/92 (Pitts and Palmer, 1994), and 1989/90 (Evans and Dowell, 1991), it is evident that the marked geographic variation seen previously is still evident.

It is particularly important to assess the trends in prevalence in this age group as these data allow an estimation of present caries attack, unmasked by any previous history of operative intervention or past disease activity. Trends over time demonstrate a modest improvement of 3.9% in overall dmft for Great Britain since 1995/96, compared to the improvement of 8.6% seen in the previous two years. Over recent years the overall trend in this age group seems to be one of modest improvement following a long plateau. The proportion affected by dentinal decay also seems to have fallen (British mean from 36.7% in 1997/98 to 35.7% in 1999/2000). There have also been some fall in the components of the dmft index (dt, mt and ft).

The care index reflects the restorative care of those who have suffered disease and has changed very little since the last survey of this age group in most regions / territories. This indicator has not regained the levels seen in the past from early national surveys of child dental health. The data in Table 1 and Figure 4 shows the wide variations in the care index across Great Britain which appears to be independent of mean caries prevalence. The magnitude of the care index should be viewed in conjunction with dmft. For the current survey it would appear that the combination reflects a small worsening in care delivery in an improving environment of oral health. It is important, however, to remember the skewed nature of the disease in the population; the British mean dmft for those with caries experience (dmft>0) was 3.88 as opposed to the overall mean of 1.57.

For the future, there is concern that inconsistent changes in consent and sampling strategies imposed locally, as a result of concerns about how best to respond to data protection and confidentiality guidance, may compromise the future validity and comparability of the BASCD coordinated Programme of NHS surveys. In this report no data can be presented for Northern Ireland following the introduction of significant changes in consent arrangements. Similar concerns are also being expressed elsewhere in the United Kingdom.

Overall, the findings from this survey show that there has been some improvement in the dental health of five-year-old children in Great Britain; that the provision of operative care for those with dentinal decay in primary teeth was low and has remained almost constant; but that significant groups remain within the population at this age who have dental disease and who are in need of dental care. There is thus a continuing need for more effective preventive and treatment services for the important pre-five age group.

Acknowledgements

The authors are indebted to the very large number of people who contribute to the BASCD co-ordinated NHS Dental Epidemiology Programme. Particular thanks are due to: Dr Cynthia Pine and Mr Nigel Thomas (BASCD R&D Associates), the "regional" NHS Epidemiology co-ordinators and trainers and to staff of the Dental Health Services Research Unit, Dundee for all their help. Professor Pitts acknowledges support from the Chief Scientist Office of the Scottish Executive Department of Health and the Medical Research Council's Health Services Research Collaboration. The views expressed are those of the authors and not necessarily those of the Scottish Office or the MRC.

References

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Mitropoulos, C., Pitts, N.B., and Deery, C. (1992): British Association for the Study of Community Dentistry criteria for the standardised assessment of dental health (1992/1993) In: BASCD trainer's Pack for caries prevalence studies 1992/1993. Dundee: University of Dundee.

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