Ths peer reviewed article was first published in the journal Tuith Online

Dental status in Scotland 1972-1998

(based on the 1998 Adult Dental Health Survey) by Nigel M. Nuttall, Dental Health Services Research Unit

This article is part 2 of 4 of an invited article series. View parts 1, 3, and 4.

This article examines how the condition of teeth in the Scottish dentate population has changed since 1978.

The number of natural teeth retained by dentate adults

The variation in the numbers of teeth in the dentate population gives some indication of the rate at which people are losing teeth and an indirect measure of how many people may be likely to require dentures in addition to their own teeth in ensuing years. Figure 1 shows that the average Scot who had some teeth in 1998 retained just over two-and-a-half more teeth than in 1972. The 1998 average of 23.8 teeth was still, however, almost one tooth less than the average for the UK as a whole.

Figure 1. Average number of teeth among dentate adults in Scotland 1972-1998

In addition to counting the number of teeth the national surveys of adult dental health classify teeth as being in one of four conditions; missing, filled but otherwise sound, sound and untreated, or decayed. The interpretation of these measures is not necessarily straightforward. The number of teeth which are sound and untreated is often as much an indication of an absence of dental treatment as a sign of dental health. Thus, high numbers of sound and untreated teeth have often been associated with those who avoid going to a dentist on a regular basis but can also be a sign of a well looked after mouth. On similar lines is the argument that filled but otherwise sound teeth can indicate past experience of disease or can also reflect having received some dental care. This leads to the now routinely found result that fillings are more common in those who attend for regular dental check-ups than in those who only attend when they have some trouble with their teeth. This would seem to suggest that attending for check-ups is associated with a poor dental outcome or more disease experience, yet these surveys repeatedly show that regular dental check-ups are associated with the positive dental outcome of the retention of natural teeth. Decay is unequivocal as a negative indicator of dental health. However, decay measured as part of traditional epidemiological surveys is not necessarily equivalent to all the caries that would be treated in clinical practice. The rule in previous national dental surveys has been to count only instances where there is definite dentine involvement and a break in surface continuity as cases of decay.

The condition of natural teeth among dentate adults in Scotland 1972-98

Figure 2 shows the condition of natural teeth among dentate adults in Scotland. The average number of missing teeth in dentate adults has been steadily declining since it was first measured on a national basis in 1972. Adults with some natural teeth in Scotland had an average of 2.6 fewer missing teeth in 1998 than in 1972. Furthermore, the condition of teeth retained is steadily improving as well. The number of teeth with untreated decay has more than halved in the last 26 years from 2.4 in 1972 to 0.9 in 1998. At the same time the number of filled otherwise sound teeth has risen from 6.5 to 8.8, and so too has the average number of sound and untreated teeth, from 12.3 to 14.1. Nevertheless, the average Scot has almost one more missing tooth and one- and-a-half fewer sound and untreated teeth than the UK average.

Figure 2.Tooth status among dentate adults in Scotland 1972-1998

Key

The effect of changing the criteria for dental caries.

It was noted earlier that tooth decay in the national surveys has traditionally been defined as lesions where caries penetrates dentine and where there is a visible discontinuity in tooth surface. There has been considerable debate whether this is an appropriate definition from the point of view of defining caries that requires treatment. One of the most significant changes with respect to assessment of dental caries in the 1998 survey has been in the collection of additional caries data. In the previous surveys in this series, with the inclusion for the first time of an assessment of dentine caries without obvious cavitation. These changes do not include lesions confined to enamel which are counted as sound for the purpose of the survey. Radiography was not undertaken.

The effect of the changes can be seen in figure 3 that looks at the findings using the traditional survey criteria and using the new caries criteria. The new caries criteria detected twice as many teeth with dentine caries (1.8) than were found with the more traditional criteria (0.9). As a consequence the average number of teeth classified as sound and untreated dropped form 14.1 to 13.6 and the average number of filled but otherwise sound teeth dropped from 8.8 to 8.4.

Figure 3 Tooth status of dentate adults in Scotland in 1998- the effect of changing the caries criteria

Key

The remaining two tables look at dental status using the new caries criteria.

Tooth Status and Age group

On the basis of a count of 32 teeth Scottish adults aged 16-24 had an average of 4.3 teeth that were not present (predominantly 3rd molars). There was a higher incidence of caries among younger adults; on average dentate adults aged between 16 and 34 had 2.2 decayed teeth compared with 1.3 among those aged 65 or over, but older adults had many fewer teeth overall. One of the most striking findings of this survey is the experience of filled but otherwise sound teeth among those aged 16-24. The youngest age group had 3.8 filled (otherwise sound) teeth on average compared with 8.9 among those aged 24-34; a difference of 5.1 filled teeth which is considerably larger than the difference between any other two adjacent age groups. This perhaps marks the beginning of a new type of dental patient entering the adult population; one who has markedly fewer existing fillings with a consequently lower need for maintenance treatment for past restorative work

Figure 4. Tooth status by age group in Scotland 1998

Key

Deprivation and tooth status

The first article in this series showed that people from areas with higher material deprivation indicated by factors such as lower car ownership and male unemployment are more likely to have lost all their natural teeth in comparison to those who live in more affluent areas. The relationship between deprivation and dental health is also found in the condition of natural teeth. People who lived in poorest areas tended to have more decayed teeth and markedly fewer filled teeth than those from affluent areas indicating that they are suffering both from a higher level of dental disease and an apparently lower exposure to restorative dentistry than the most affluent.

Figure 5. Tooth status by deprivation category (DEPCAT) in Scotland 1998

Key

Thanks and Disclaimers

The DHSRU would like to thank all the dentists and interviewers who often worked unsocial hours to undertake the dental examinations and people who gave their time to be interviewed and dentally examined.

This work was undertaken by a consortium comprising the Office for National Statistics and the Dental Schools of the Universities of Birmingham, Dundee, Newcastle and Wales who received funding from the United Kingdom Health Departments; the views expressed in this publication are those of the authors and not necessarily those of the Health Departments nor of the other members of the consortium.

Nigel Nuttall acknowledges support from the Chief Scientist Office of the Scottish Executive who do not necessarily share the views expressed.