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Scottish Prisons' Dental Health Survey 2002

12. The influence of length of time in prison

This section of the report looks at changes in dental health over the length of time spent in prison. We have included only subjects who have served at least 6 months and have at least 10 teeth (N = 245, unweighted data). Prisoners serving less than 6 months may not access the prison dental service, except perhaps for emergency dental care, and they were excluded from this part of the analysis.

Following time trends in the level of decay and restorations gives some indication of the time taken to render a prisoner dentally fit and the overall provision of dental care in Scottish prisons.

The decayed, missing and filled tooth index (DMFT index) is the sum of the number of decayed teeth (DT), missing teeth (MT) and filled teeth (FT) of each individual. Individual scores can be averaged to give a mean score for a population.

Spearman's rho is a measure of rank correlation and is used as the two variables "length of time in prison" and "DMFT" may not be normally distributed. Using Spearman's correlation coefficient there is a statistically significant relationship between the length of time spent in prison and the number of decayed teeth and filled teeth (Table 21). The number of decayed teeth falls and the number of filled teeth increases. The number of missing teeth is not significantly correlated with length of time in prison.

The Care index is the proportion of total DMFT, which is filled, expressed as a percentage (FTx100/DMF). It shows the overall level of operative care received and using the correlation analysis, this also increases with length of time in prison.

TABLE 21 - Correlations of length of time in prison and dental health

The average number of decayed teeth of prisoners serving 6 to 12 month sentences was 2.38 teeth (Table 22). Over the next 12 months there was a 37% reduction in mean DT to 1.49 and a further reduction over the next 12 months to around about a mean figure of 1 tooth. This is then reasonably stable for the inmates in prison for up to 4 years. This shows that it takes two years for the needs of dental prisoners to be successfully reduced to a sustainable level. The number of filled teeth also increases for the first two years of a prisoner's sentence suggesting (on average) a 2-year lag from entering prison to finishing a course of dental treatment.

Although this is a somewhat crude analysis, it shows that it takes two years for the dental needs of prisoners to be addressed and is an area where improvements to the service could be made to provide more timely dental care.

TABLE 22 - DMFT index and components with reported length of time served in prison

13. Comparisons of the dental health of the prison population to the Scottish Population.

The largest, most recent data set available for the adult population of Scotland was the 1998 UK ADHS and this section compares the dental health, attitudes and behaviour of the prison population to the Scottish population from the 1998 UKADHS. The age and gender distribution of the prison population does not match that of the Scottish population and the data from the 1998 national survey has been reweighted to match the Prison population and allow direct comparisons. As the national survey used only the categories of male and female, the male prison population (adults and young offenders) has been amalgamated into a single male group for comparison to Scottish males.

If the sample of 559 subjects on which this study is based had been drawn at random from the prison population, too few women and young men in YOI institutions would have been included to allow analyses of these groups. Therefore, young men and women were deliberately over-sampled. When these groups are combined to describe all male prisoners or the whole prison population, weights were applied as shown in Appendix 7.

As described in the statistical appendix that accompanied the 1998 report of this survey, men and younger age groups were under-represented in both the overall survey and the sub-group who agreed to dental examination. Therefore, this sample is not the ideal comparator for a younger, male prison sample. Very large weightings were applied to create a Scottish sample with the same sex ratio and a similar age breakdown to the sample of prisoners. All statistics based on the comparisons with UKADHS should be treated as weak and only for general discussion purposes.

Comparisons of Prison Population to the 1998 UK Adult Dental Health Survey

Reported treatment preferences

Table 23 compares the reported preferences of the male and female prisoners to the Scottish population. When asked,

"If you went to a dentist with an aching back tooth would you prefer to have it taken out or filled (supposing it could be filled)?"

The percentage of male prison respondents who preferred a filling to the extraction of a back tooth was slightly lower but not significantly different from the Scottish population. The female prisoners again reported a lower figure in favour of restoring a back tooth which was not significant. Overall any differences between all prisoners and the population were not statistically significant. (Table 23).

When the treatment option was,

"If a dentist said that a front tooth would have to be extracted (taken out) or crowned, what would you prefer?"

The percentage of male prison respondents who reported they would prefer a crowned front tooth to an extraction was again slightly lower but not significantly different from the Scottish population. The female prisoners also reported a lower figure in favour of crowning a front tooth which was not statistically significant.

TABLE 23 - Proportion of respondents in prisoner group reporting preferences

Time since last visit the Dentist?

Comparisons of the length of time prisoners reported since they had last visited a dentist (whether a prison dentist or not) were not statistically different from the Scottish population (Table 24).

TABLE 24 - Percentage of prisoner groups reporting length since last visit a Dentist (including a prison dentist)

Reason for your last visit to the dentist

However, the reasons prisoners reported for their last visit to a dentist (either in prison or not) were very different from the Scottish population. In all cases (male, female and overall) fewer attended for a regular dental check-up and significantly more attended because of toothache or other trouble with their teeth (Table 25). This shows that the prison population are inclined to wait until they have pain from their teeth, making removal of a tooth the more likely treatment option. They also do not attend for regular check-ups. Regular dental attendance means small cavities can be identified and restored before they cause pain. Early gum disease can be treated before the teeth become loose and fall out, and dental emergencies can be prevented.

TABLE 25 - Proportions of groups reporting reason for last visit to the dentist (including a prison dentist)

The results shown in tables 24 and 25 seem to contradict each other. How can fewer prisoners attend for dental check-ups and yet there is no difference in the length of time since their last dental visit, between prisoners and the Scottish population? The contradiction can be explained by the frequency of dental pain. If people who do not attend for check-ups get toothache, then they are usually forced to attend a dentist for relief of symptoms. This can often occur within a 12-month period and gives the result of similar attendance patterns over time, but for different reasons. Typical visits are for regular check-ups for the Scottish population, but for relief of pain in the prison population.

Reported dental treatment previously received.

Table 26 compares the types of dental care previously received by prisoners and the Scottish population respectively. There were no differences between the percentages reporting receiving fillings, and those having sedation for dental treatment. A larger percentage of female prisoners reported having had an extraction but this difference was not statistically significant.

A consistent finding across both genders, and overall, was a significantly lower percentage of prisoners of all categories who had had orthodontic treatment. Orthodontics is an outpatient speciality of dentistry concerned with the correction of malocclusion and dentofacial anomalies which may range from major craniofacial discrepancies, such as cleft lip and palate, to minor irregularities of the teeth. Treatment usually involves the wearing of orthodontic appliances (braces), with or without the extraction of teeth. Although incidence of malocclusion is homogenous throughout the child population, there is a recognised social class gradient of patients who have received orthodontic treatment. This finding may simply reflect the social background of the prison population.

TABLE 26 - Proportions of groups reporting dental treatment previously received.

Comparison of percentages with teeth, dentures or both

Table 27 compares the distribution of people with only natural teeth, only dentures and a combination of them both. In all cases a smaller percentage of the prison population had only natural teeth. Greater proportions of prisoners had dentures either in combination with natural teeth or dentures alone. In all categories this was statistically significant and reflects an increased need for the prison dental service to provide a greater proportion of dentures to prisoners, especially to younger prisoners.

TABLE 27 - Comparison of proportions of groups with teeth, dentures or both.

Comparison of dental decay, Males

Table 28 compares the male prison population with the UKADHS results. There was no statistical difference in the mean number of decayed teeth but the prison males had fewer filled teeth. Male prisoners also had fewer standing teeth.

The % D4T>0* (severe decay into pulp, probably requiring tooth extraction) was 3 times higher in the prison population compared to the Scottish population confirming unmet need, neglect and greater severity of decay.

^* % D4T>0, this is the percentage of group with decay at the pulpal level (D4 level) which was greater than zero.

TABLE 28 - Males, dental decay

Comparison of dental decay, Females

Table 29 compares the female prison population with the UKADHS results. There were statistical differences in the mean number of decayed, filled and standing teeth showing considerably higher levels of dental decay.

The percentage with decayed teeth was significantly higher among female prisoners and the severe decay (% D4T>0) was 14 times higher in the prison population compared to Scottish females. This is a finding which confirms huge unmet need, dental neglect and markedly greater severity of decay. The natural history of tooth decay means that individuals arrive in prison with already high levels of dental decay and severe decay.

TABLE 29 - Females, dental

Comparison of dental decay, all prisoners

Table 30 compares all the prison population with the UKADHS results. As expected there are statistical differences in the mean number of decayed, filled and standing teeth, with the prisoners having fewer filled teeth.

The severe decay (% D4T>0) was 3 times higher in the prison population compared to the Scottish population confirming unmet need and higher severity of decay.

TABLE 30 - Dental decay, all prisoners

14. Oral Health Impact Profile in a Prison Population

Introduction

Slade and Spencer (1994) published a device for measuring peoples' perceptions of the impact of dental conditions on their lives: Oral Health Impact Profile or OHIP. It uses responses to a set of standard questions to quantify the impact of an individual's oral health on their subjective feelings.

Their original version consisted of 49 questions, which was shortened to 14 measuring 7 dimensions of wellbeing in the short form OHIP-14. This instrument was used in both the 1998 ADHS and in the current survey (with one obvious change). Question 12 (15 in the prison questionnaire) was "In the past 12 months have you had difficulty doing your usual job because of problems with your teeth or dentures?" for the ADHS but "job" was replaced with "activities" for the prison survey. All of the current survey participants answered the OHIP questionnaire, but only those with teeth were included in the analyses comparing the prison with the ADHS Survey. This is because in the ADHS, only those with teeth were asked the OHIP questions.

Results were compared using linear chi-square analysis with Bonferroni's correction. As with all of the comparative results the ADHS samples were weighted to match the prison sample in age distribution and gender ratio. As the necessary weightings were very large, this comparison is statistically weak and the results should be treated with caution. The male prison sample, when compared with the female prison sample, was weighted to correct for the over-sampling of YOI inmates.

Results and Discussion

The answers from the OHIP 14 were combined and compared between groups. There were no statistical differences between adult males and male young offenders. Overall, females were more likely then males to report they suffered from problems. These involved painful aching in the mouth, feeling self conscious, tense, embarrassed, irritable, psychological discomfort, psychological disability and social disability ( Appendix 8, Table A). The male/female difference in the prison population was not found in the ADHS.

The prison population is more dissatisfied with their dental health than the general population as represented by the ADHS survey for Scotland. The results suggest that the differences are more extreme for the female sample ( Appendix 8, table B). The percentage of female prisoners reporting problems in response to the OHIP questions was statistically higher than the female ADHS population in every case. For male prisoners it was higher for pain, feeling tense, unsatisfactory diet, interrupted meals, difficult to relax, embarrassed, irritable, usual activities, life less satisfying, disability, physical handicap, psychological/social disabilities and handicap.

Further analyses were undertaken comparing groups with and without dental problems. Only those with teeth were included in this analysis ( Appendix 8, Table C). Overall, those with disease in the upper incisors or with fewer standing teeth tended to report more problems. Disease in the upper incisors appeared to impact more strongly than loss of teeth on women's OHIP scores.

15. Survey Conduct

The success of this survey was entirely reliant on the co-operation of prison staff and prisoners. The clearest example of this was when Barlinnie prison staff were seconded to Shotts Prison to deal with unrest, the survey stopped

An improved response was obtained by the survey team visiting the Residential Halls as opposed to bringing subjects to a central point.

The visit to HMP Peterhead coincided with a hastily convened meeting of prison officers which reduced the final number of prisoners seen.

The poor response in Glenochil was reported to be due to recent DNA testing of prisoners to try to link them by forensic evidence to unsolved crimes. The dental examination was reported to be seen as a clandestine method of taking a buccal cheek scraping. Also the use of the word "sample" as in "sample of prisoners" in the information letter for prisoners may have been misinterpreted.

A small incentive such as a free toothbrush might have helped to improve participation in the survey although the response rate overall was satisfactory. This was not included in the study design as we were aware that it may have reduced the takings of the prison shop.

16. Conclusions

The results of the survey show considerable unmet dental need in the prison population compared to the Scottish Adult population.

1 Compared to the general population, prisoners had significantly

• fewer standing teeth

• more decayed teeth,

• fewer filled teeth and

2 The prevalence of severe decay, as classified by teeth with decay which extends into the dental pulp, was three times higher in the prison population than in the general population.

3 In female prisons severe decay prevalence, as classified by teeth with decay which extends into the dental pulp, was fourteen times higher than the female Scottish population.

4 It was shown to take up to 2 years for the dental health of prisoners to improve to a stable level.

5 More prisoners have dentures than the general population .

6 Prisoners report they are less likely to attend for regular check-ups than the general population.

7 Compared with the general Scottish population there was no difference in the proportion of prisoners who reported that they had received fillings, extractions or sedation for dental treatment, but a significantly lower percentage of prisoners had received orthodontic treatment than the general population.

8 Female prisoners had significantly higher levels of self-reported anxiety about visiting a dentist than male prisoners.

9 Almost all prisoners with teeth reported they carried out toothbrushing at least once a day.

Acknowledgements

Joseph (Lenny) Allen, Jack Bonnar, Lyndon Braddick, Lisa Colston, Paul Cushley, Graham Eadie, Tom Ferris, Frank Gibbins, Heather Keir, Diane Lawson, Mairi MacLeod, David McColl, Kenny McGeachie, Robert Maxwell, John Peatie, Nigel Pitts, John Porter, Eileen Stewart, Carol Stirling, Patrick Sweeney, Carolyn Thompson, Gail Topping, Evelyn Tosh, David Trotter, Mr Keith Woods, The Prisoners and The Prison staff.

References

Armitage P, Berry G and Matthews JNS, Statistical methods in Medical Research 4 ^th edition. Blackwell Science, Oxford 2002.

Daly B, Watt RG, Batchelor P and Treasure ET 2002. Essential Dental Public Health, Oxford University Press, Oxford 2002.

Gray PG, Todd JE, Slack GL and Bulman JS. Adult dental health in England and Wales in 1968. HMSO London 1970.

Royal College of Physicians (1990) Research involving patients. Royal College of Physicians, London.

Slade GD & Spencer AJ (1994) Development and evaluation of the oral health impact profile. Community Dental Health, 11, 3-11.

SPS (2001) Scottish Prison Service Annual Report 1999/2000.

Todd JE and Whitworth A . Adult dental health in Scotland 1972. HMSO London, 1974.

Titsas A and Ferguson MM (2002) Impact of opiod use on dentistry. Australian Dental Journal. 47, 94-98.

Todd JE and Walker AM. Adult dental health Volume 1 England and Wales 1968-78 HMSO London, 1980.

Todd JE, Walker AM and Dodd P. Adult dental health Volume 2 United Kingdom 1978 HMSO London, 1982.

Todd JE and Lader D. Adult dental health 1988 United Kingdom, HMSO London, 1991.

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