The changing pattern of dental disease over 50 years.
Explore the source record for details and available documents.
Adult↗
Biomedical subjects
M C Downer
Publications and source records attributed to M C Downer.
The British Association for the Study of Community Dentistry.
Explore the source record for details and available documents.
Child↗
Presidential address to the British Association for the Study of Community Dentistry, Manchester, May 1998.
Explore the source record for details and available documents.
Community Dentistry↗
Health gain from restorative dental treatment evaluated by computer simulation.
OBJECTIVE: To simulate the influence over time of relevant factors on health gain from restorative dental treatment under varying assumptions and to compare outcomes with those resulting under a 'do nothing' scenario. DESIGN: A decision model was used in a computer simulation of the caries process in posterior approximal tooth surfaces. The effect of superimposing restorative treatment, based on bitewing radiology, was incorporated. Input data came from current observational studies and included caries progression rates, notional survival times of restorations, and sensitivity (Sn) and specificity (Sp) of treatment decision making by a high (A) and a low (B) performing dentist. Utility values, on a scale 0-1, for different tooth health states were obtained from questioning 92 adults of appropriate age. SETTING: By assumption, the primary dental care sector. PARTICIPANTS: A hypothetical population, initially 14-15 years old. INTERVENTIONS: Class II amalgam restorations. OUTCOME: Computed in utility based units (UBUs) as sums of the product of numbers of sound, carious and restored surfaces and their utility values. Health gain (in UBUs) was assessed relative to interim end point UBUs pertaining under 'do nothing'. RESULTS: One thousand approximal surfaces, designated initially as 920 sound, 51 carious and 29 filled were followed in the model over 10 years. The greatest health gain (33.16 UBUs) was from dentist A (Sn = 0.23, Sp = 0.99, 50 per cent restoration survival rate = 10 years, caries rate = 4.4% per annum). The least was from dentist B (Sn = 0.52, Sp = 0.88, 50% survival = 5 years, caries rate = 0.0% per annum) representing a loss of 17.07 UBUs compared with 'do nothing'. CONCLUSIONS: Results suggest that caution is advisable when making positive decisions to restore on the basis of bitewing radiographs.
Adolescent↗
An interim determination of health gain from oral cancer and precancer screening: 3. Preselecting high risk individuals.
OBJECTIVE: To perform a sensitivity analysis using a decision model for simulating opportunistic screening for oral cancer and precancer in order to obtain an estimate of health gain from screening high risk dental patients, identified with the aid of artificial intelligence. DESIGN: A hypothetical opportunistic screening programme based on preselection of high risk patients was compared with screening all eligible patients and with a 'do nothing' scenario. The basic assumptions and data used in the model have been described previously. SETTING: Screening would be carried out in dental practices. PARTICIPANTS: A notional population of 100,000 adults of average age 55 years and 20 years life expectancy. INTERVENTIONS: Systematic clinical examination of the oral mucosa of high risk individuals identified by artificial intelligence on the basis of personal characteristics and life style. OUTCOME MEASURES: QALYs and equivalent lives saved RESULTS: The following estimates of health gain were obtained: the preselected screened group (n = 25,000) would achieve 1,993,294 QALYs. Without preselection, screening an unselected population of 100,000 eligible adults would result in 1,993,094 QALYs. Under the 'do nothing' scenario, 100,000 unscreened individuals would achieve 1,992,982 QALYs. Selective screening could avoid the equivalent of 15 deaths per 100,000 subjects examined. Screening preselected subjects at heightened risk would save the equivalent of two to three times the number of healthy lives compared with non-selective screening. Only one quarter of the population would need to be examined. CONCLUSIONS: Opportunistic screening of preselected dental patients for oral cancer and precancer appears to be a promising health promotion strategy and should be subject to formal economic appraisal.
Cost-Benefit Analysis↗
An interim determination of health gain from oral cancer and precancer screening: 1. Obtaining health state utilities.
OBJECTIVE: To obtain preliminary health state utility values for oral precancer, and stage 1 and stage 2 (or greater) oral cancer, for use in a study involving quality of life measurement. DESIGN: Members of the general public were personally interviewed and asked to complete a standard gamble questionnaire in which each individual had to choose between having oral cancer or precancer (a description of each stage and its treatment was given), and being perfectly healthy but with a probability (p) from 0 to 1, of immediate death. There were three questions, the first related to a state of oral precancer, the second to a small cancer (< 2 cm) and the third to a large oral cancer (> 2 cm). The utility of each state was equal to the probability that the subject would opt for having the disease (1-p). The pooled responses of all subjects were analysed using a Wilcoxon matched-pairs signed-ranks test. SETTING: The premises of a commercial company. PARTICIPANTS: A convenience, quota sample of 100 employees aged 40 years or over. RESULTS: The mean utility values obtained were: oral precancer = 0.92; small oral cancer = 0.88; large oral cancer = 0.68. There was a significant difference between all three states (P < 0.05). CONCLUSIONS: The study relied on a convenience sample to elicit the public's perceptions of different oral cancer states. Nevertheless, despite this limitation, it was considered that the utility values derived were suitable for incorporation in measurements of quality adjusted life years.
Adult↗
An interim determination of health gain from oral cancer and precancer screening: 2. Developing a model of population screening.
OBJECTIVE: To design a simulation model of population screening for oral cancer and precancer and to obtain estimates of quality adjusted life years (QALYs) and lives gained from screening, using decision analysis. DESIGN: A hypothetical opportunistic screening programme was compared with the status quo (no screening). Variables included in the model were attendance (50 per cent of the eligible population); prevalence of oral cancer (0.098 per cent) and precancer (2.57 per cent), positive (0.67) and negative (0.99) predictive values of screening, stage distribution of cancer (40 per cent stage 1, 60 per cent stage 2+ without screening; 60 per cent stage 1, 40 per cent stage 2+ with screening); average survival (precancer, 19.2 years; stage 1, 14.6 years; stage 2+, 10.8 years); and the public's perceived utilities of the various outcomes (health, 1.00; precancer, 0.92; stage 1 cancer, 0.88; stage 2+ cancer, 0.68). One cycle of the programme was modelled. SETTING: Screening would be carried out in dental practices. PARTICIPANTS: A notional population of 100,000 adults of average age 55 years and 20 years life expectancy entered each decision pathway (screening or status quo). INTERVENTIONS: Systematic clinical examination of the oral soft tissues. OUTCOME MEASURES: QALYs and equivalent lives saved. RESULTS: Assuming 50 per cent attended, the population offered screening achieved 1,993,094 QALYs. With no screening the corresponding end point was 1,992,982 QALYs. The gain from screening was therefore 56 QALYs representing an equivalent of 2.8 lives saved. CONCLUSIONS: Though a simplification, this model is likely to be more reliable than intuitive prediction and is amenable to sensitivity analysis of different screening strategies. A modest health gain from screening was predicted by the model.
Adult↗
Oral health week.
This article reports on the Oral Health Week held in December 1994 and focuses on an initiative by the BDA which organised dentists and volunteers from Age Concern in a project to look at oral health for the elderly. It examines the aims and the results of the week and draws some useful conclusions on improving the outcome if a project such as this were attempted again.
Aged↗
Evaluation of a year long, hands-on restorative dentistry course for practitioners.
Continuing education is now seen as an essential part of professional practice and ways to improve the effectiveness of these courses are always under review. This article describes a year long, part-time hands-on restorative dentistry course and reports on the results. The aim of the course was to encourage those practitioners to attend continuing education courses who would not usually do so, and devise ways to maximise the usefulness of the course content.
Adult↗
The epidemiology of oral cancer.
OBJECTIVES: To examine the epidemiology of oral cancer in England and Wales from 1901 to 1990 using trends in mortality and incidence rates. SETTING: Data were obtained from OPCS archives for mortality and incidence of malignant neoplasia of the oral cavity (ICD 141, 143-146). Age-specific and age-standardised rates were calculated for both genders. Mortality data were available from 1901 but national incidence figures only commenced in 1962. RESULTS: Despite overall reductions for oral cancer in England and Wales during this century, significant increases in mortality and incidence have occurred in younger males during the last 30 years. These are associated with clear birth cohorts. No such cohort effects are apparent in females, despite similar though less pronounced trends. CONCLUSIONS: These results support similar studies in other parts of the UK and Europe. In the future there may be a substantial increase in the burden of new cases of oral cancer as birth cohorts with rising incidence rates enter age groups with higher disease frequencies. It is possible that raised alcohol consumption during the last 40 years may be responsible for the increases. This report reinforces the necessity to evaluate preventive programmes for oral cancer in the UK.
Adult↗
Restorative treatment decisions from bitewing radiographs--performance of dental epidemiologists and general dental practitioners.
The object of the study was to compare the performance of a group of eight trained and standardized dental epidemiologists making restorative treatment decisions with that of a group of 20 general dental practitioners. Both groups read the same set of 15 pairs of simulated bitewing radiographs. For each approximal tooth surface image, the examiners were asked to record on a six-point rating scale the confidence with which they would or would not place a restoration. A histological gold standard was available, based on microscopic evaluation of sections of the extracted teeth used for study. The reference criterion was "caries into dentine". The only statistically significant differences in performance between the two groups were at the "definitely" plus "probably" restore rating level. For the proportions of correct decisions out of all treatment decisions at this level, the epidemiologists scored 89% compared with 86% for practitioners (P < 0.01) while for Youden's J index, the corresponding values were 0.44 and 0.34 (P < 0.05). The findings suggest that the benefits in improved performance from examiner training may be small.
Bicuspid↗
The caries decline. A comment in light of the UK experience.
Explore the source record for details and available documents.
Adolescent↗
Training examiners for a national epidemiological survey of oral mucosal lesions.
Ensuring the validity and reliability of data collected in epidemiological surveys is an important consideration. The purpose of the present report is to describe a training and calibration programme for 16 examiners taking part in a national survey of oral mucosal lesions and to present an evaluation of the results. The programme included the distribution of a pictorial manual to participants and a series of lectures followed by three diagnostic sessions, two using slides and the last involving patients. At the final session, the trainees classified 88 per cent of 16 patients correctly in comparison with the definitive diagnoses of the trainer, and their sensitivity on recording oral carcinoma, leukoplakia and lichen planus was at least 0.88. However, correctly classifying submucous fibrosis on the basis of slides alone proved problematic. At the conclusion, the diagnostic accuracy of two examiners for all types of lesion remained appreciably lower than the majority. Training strategies for various types of study are discussed. The method reported is considered to represent a model approach to training and calibrating examiners for this type of survey work.
Dental Health Surveys↗
Evaluation of health care workers' accuracy in recognising oral cancer and pre-cancer.
The aim of the study was to evaluate dental health care workers' ability to recognise oral cancer and pre-cancer from colour photographic slides. A set of 80 slides was prepared, 40 were negative (normal mucosa or lesions with no malignant potential) and 40 were positive (cancer or potentially malignant lesions). The slides were arranged in random order and projected in a standard format. The performance was evaluated in terms of mean sensitivity, specificity, mean correct score and likelihood ratio. There were no significant differences between the three groups of dentists (consultants, juniors hospital dentists and general dentists), all performed better than the auxiliaries. The chances of a consultant making a correct decision were 5.5 times better than for an auxiliary and 2.7 times better than for a junior hospital dentist. The slide show enables a comparison of health care workers to be made and may be useful for the evaluation, training and calibration of examiners for an oral cancer screening programme.
Calibration↗
The use of artificial intelligence to identify people at risk of oral cancer and precancer.
Artificial intelligence is being used increasingly as an aid to diagnosis in medicine. The purpose of this study was to evaluate the ability of a neural network to predict the likelihood of an individual having a malignant or potentially malignant oral lesion based on knowledge of their risk habits. Performance of the network was compared with a group of dental screeners in a screening programme involving 2027 adults. The screening performance was measured in terms of sensitivity, specificity and likelihood ratios. All subjects were examined independently by a dental screener and a specialist, who provided a definitive diagnosis, or 'gold standard', for each individual. All subjects also completed an interview questionnaire regarding personal details, dental attendance and smoking and drinking habits. The neural network was trained on 1662 of the screened population using ten input variables derived from the questionnaire along with the outcome of the specialist's diagnosis. Following training, the network was asked to classify the remaining unseen proportion (365 individuals) of the screened population as positive or negative for the presence of cancer or precancer. The overall sensitivity and specificity of the dentists were 0.74 [95% confidence interval (CI), 0.62-0.86] and 0.99 (95% CI, 0.985-0.994) respectively compared with 0.80 (99% CI, 0.55-1.00) and 0.77 (95% CI, 0.73-0.81) for the neural network. In view of the potential costs involved in implementing a screening programme, this neural network may be of value for the identification of individuals with a high risk of oral cancer or precancer for further clinical examination or health education.
Adult↗
The 1993 national survey of children's dental health.
The 1993 national survey report shows encouraging evidence of general improvements in children's dental health compared with earlier surveys in 1973 and 1983. There have been dramatic declines in dental caries at all ages and this is evident in the different parts of the United Kingdom and in all social classes. However, among 5-year-old children average caries levels have remained unchanged since 1983, although a higher proportion now have no known decay experience. The amount of decay treated by restoration as a proportion of total caries experience has fallen in all age groups and the disease appears to be becoming concentrated at higher levels in a diminishing number of children who are not obtaining dental care. A disturbing finding was the high prevalence of dental erosion, particularly in the primary dentition. Other findings included more than half of children in Scotland and Northern Ireland having fissure sealants, improved parental knowledge about preventing dental disease, reduced numbers of orthodontic extractions and a reduction of one-third in the rate of traumatised permanent incisors. Children must be regarded as the number one priority for dental services in order to safeguard the dental health of rising generations, and renewed efforts must be made to further reduce their disease levels through population based preventive measures.
Adolescent↗