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Biomedical subjects

M C Downer

Publications and source records attributed to M C Downer.

At least 55 records · Page 3Linked to original sources
PubMed1995

Attendance and compliance at an oral cancer screening programme in a general medical practice.

The purpose of this study was to measure the attendance and compliance rates in a demonstration invitational screening programme for oral cancer. 4348 subjects aged 40 years or over registered at an inner city medical practice in north London were invited for screening by post. The socioeconomic profile of the group was determined by analysis of residential areas. Screening was conducted by one of several dentists and a referral pathway was established for patients requiring follow-up. Attendance rates for screening and referral for follow-up were measured. The response rate was 985/3826 (25.7%) after removing 522 subjects whose invitations could not be delivered or who refused appointments. No reply was obtained for 2841 patients. Attendance for referral of lesions considered to have malignant potential was 67% (8/12), compared to 92% (11/12) for patients requiring referral for incidental benign lesions. The low compliance suggests that oral cancer screening may not be able to achieve the desired benefits of reducing morbidity and mortality, and establishment of such a programme may not, therefore, be cost-effective. Further research is required into how to identify people in high risk groups and motivate them to present themselves for screening.

Adult↗
PubMed1995

Case-control study of oral dysplasia and risk habits among patients of a dental hospital.

Several studies have investigated risk factors for oral cancer but few have considered precancer. Records accumulated from 1975 to 1993 of dental hospital patients with histologically confirmed oral dysplasia provided the opportunity for a retrospective case-control study of the association between oral precancer and smoking tobacco and drinking alcohol. Seventy sets of case notes were available and each case was matched with records of a control subject, known to be free from dysplasia from another study, for birth date, gender and presumed ethnicity. The relative risk (OR) of having a dysplastic lesion for smokers compared with non-smokers, or ex-smokers for > 10 years, was 7.00. Logistic multiple regression revealed a dose-response relationship for tobacco dependent upon the level of cigarette consumption. Also subjects with moderate or severe dysplasia included a higher proportion of smokers than those with mild dysplasia. No overall increased risk from alcohol was found. However, the proportion of subjects who drank spirits was significantly higher among cases than controls. The study reaffirms the role of dental practitioners in identifying individuals at risk of mucosal disease, the importance of public education about the risk factors, and the necessity for counselling patients with precancerous lesions on avoiding further risk.

Alcohol Drinking↗
PubMed1995

Evaluation of screening for oral cancer and precancer in a company headquarters.

Oral cancer and precancer appear to fulfil many of the criteria for a disease suitable for mass screening. Several commercial organisations in the UK have introduced screening for their employees. One program has been formally evaluated over the course of 1 yr. Of 553 company headquarters staff aged > or = 40 yr, 292 (53%) responded to the well-publicised screening invitation and received a simple clinical examination of the oral mucosa from one of two company dentists. In addition, 17 staff were screened from a separate company work-site. After screening, subjects were examined independently by an oral medicine specialist with access to the relevant diagnostic aids. The dentists' screening decisions were validated against the specialist's definitive diagnoses (the 'gold standard'). The true prevalence of subjects with lesions diagnosed as positive (white patch, red patch or ulcer of greater than 2 weeks' duration) was 17 (5.5%). Overall, sensitivity was 0.71 and specificity, 0.99. The compliance rate to screening among headquarters subjects in seven occupational categories did not differ significantly from the occupational profile for all headquarters personnel. Estimates of relative risk of a positive diagnosis were calculated by logistic regression for five independent variables; gender, age, moderate smoking, heavy smoking, and smoking combined with greater than low risk alcohol consumption. Only heavy smoking (> or = 20 cigarettes per day) produced a significant odds ratio (3.43, P < 0.05).

Adult↗
PubMed1995

Annual screening for oral cancer and precancer by invitation to 60-year-old residents of a city in Japan.

Since 1986, annual screening for oral cancer and precancer by postal invitation has been undertaken among 60-year-old residents of Tokoname city, Japan. Clinical examination of the oral soft tissues is performed by groups of four different, specially trained general dental practitioners in the city health centre on one day each year. Following screening each subject receives an individual consultation with an oral medicine specialist. Individuals considered to need full diagnostic follow up or treatment are advised to attend a secondary care referral facility. Between 1986 and 1993, 802 out of 5187 eligible residents (15.5 per cent) were screened of whom 38 (4.7 per cent) were designated by the screeners as positive for oral cancer, erythroplakia, leukoplakia, lichen planus or chronic candidosis. Of these, 32 were referred and 25 attended for follow up examination in hospital departments by specialists with full diagnostic back up facilities. Twenty subjects were confirmed as having a potentially malignant lesion. For these referred patients only, the proportion of correct decisions by the screeners out of all oral cancer/precancer screening decisions was 81 per cent. Positive and negative predictive values for those attending for follow up were 0.80 and 0.82 respectively. Ways of improving the effectiveness and adequacy of the programme are considered.

Biopsy↗
PubMed1995

Characteristics of participants and non-participants in annual mass screening for oral cancer in 60-year-old residents of Tokoname city, Japan.

Three thousand one hundred and twenty three 60-year-old residents of Tokoname city, Japan, were eligible to take part in an ongoing annual mass screening programme for oral cancer and precancer during the years 1986-1990. All received a mailed questionnaire to ascertain details of their personal circumstances, lifestyle factors and medical history. One thousand six hundred and sixty eight (53 per cent) responded and of these, 347 plus an additional 89 non responders, totalling 14 per cent of the sample, subsequently attended for screening. Those screened were significantly more likely than non participants to have taken part in other general health or cancer screening, to report past histories of diseases or conditions with severe subjective symptoms and to have access to the screening facility on foot, by bicycle or by car. There were no significant differences between the groups in their smoking habits or alcohol consumption. Ways of improving compliance in screening are considered and in particular, the need for further strengthening the complementary public education programme to increase its effectiveness is highlighted.

Alcohol Drinking↗
PubMed1995

Evaluation of a screening test for the early detection of oral cancer and precancer.

The purpose of this study was to establish the sensitivity and specificity of a clinical examination for the detection of early oral cancer and precancer. A screening programme was conducted over a period of one year and 2027 subjects aged 40 years and over were examined. Screening took place at two sites; opportunistically in outpatient departments at a dental hospital and by postal invitation at an inner city medical practice. The screening procedure included a questionnaire on habits and an oral examination by two independent dentists. The first examining dentist (the screener) was either a general dental practitioner, a community dental officer or a junior hospital dentist. There were 24 dentists in the screener group. A second single examining dentist (a specialist) provided the definitive diagnosis, or 'gold standard', with which the screeners' results were compared. A screen was defined as positive if a white patch, a red patch, or an ulcer of longer than two weeks duration was detected. Each subject was categorised as either positive or negative by both the screener and the specialist. The screener and specialist were unaware of each other's findings. The prevalence of disease according to the specialist was 2.7 per cent. The results for all 24 screeners were pooled and gave an overall sensitivity of 0.74 (95 per cent CI, 0.62 to 0.86), specificity of 0.99 (95 per cent CI, 0.985-0.994) and positive and negative predictive values of 0.67 and 0.99 respectively.

Adult↗
PubMed1995

Initial caries attack and average progression rates in 12-year-old Isle of Wight children.

Initial caries attack and progression rates of posterior approximal carious lesions were assessed based on 12-year-old school children residing on the Isle of Wight. Bitewing radiographs of a sub-sample of 165 subjects were randomly selected from the control group of a dentifrice clinical trial which took place between 1984 and 1987. Of the approximal surfaces that were caries-free at the first examination 71 per cent of the same surfaces remained caries-free after three years, an overall initial caries attack rate averaging 10.7 per cent per annum. Of the mesial surfaces of first permanent molars, 455 were initially caries-free, 67 per cent of which remained so after a three year period. The attack rate of this specified surface was 12.4 per cent per annum. The majority of surfaces that were caries-free at the start of the investigation would therefore be expected to remain so at least three years later. Caries progression appeared to be a slow process with only 12 per cent of initially carious outer enamel surface lesions penetrating into dentine after one year. After two years this had increased to 46 per cent and after three years, to 62 per cent. For a similarly defined group of individuals it would appear likely that the majority of early enamel lesions would not reach dentine within two years. For a substantial number of subjects this would extend to at least three years.

Child↗
PubMed1994

The 1993 national survey of children's dental health: a commentary on the preliminary report.

A preliminary report of the 1993 national survey of children's dental health shows encouraging evidence of a further marked decline in caries throughout the United Kingdom compared with earlier surveys in 1973 and 1983. Over the course of 20 years total decay experience (dmft/DMFT) among children in England and Wales has fallen by 55% in deciduous teeth at 5 years of age, 82% in permanent teeth at 8 years, 75% at 12 years and 74% at 14 years. Whereas in 1973 only 7% of 12-year-old children had no experience of permanent tooth decay (DMFT = 0), by 1993, 50% were caries-free. Nevertheless the marked regional inequalities in dental health of earlier years have been perpetuated with much higher caries levels in Scotland and particularly Northern Ireland than in England currently. It is also apparent that in 5-year-old children the decline in caries in deciduous teeth has now levelled out over many areas of the country. Particular groups of children are still at high risk to the disease and the need in many areas for population preventive strategies such as water fluoridation remains.

Adolescent↗
PubMed1994

Evaluating health gains from restorative dental treatment.

A simulation of the caries process over time in posterior approximal tooth surfaces was modelled and tentative evaluations made of health gain from restorative treatment under two sets of assumed conditions. Using published data, the decision model allowed the influence of three variables to be reflected in sensitivity analysis, 1. caries progression, 2. diagnostic accuracy, 3. survival time of fillings. Progress of 50 hypothetical initially sound surfaces, 40 with enamel, and 10 with dentine lesions, was followed over two notional, successive 5-yr time periods. A surface could terminate as sound, enamel lesion, dentine caries, filled, refilled, refilled twice or extracted. Utility values were applied to the end state frequencies to evaluate health gain (from 0 to 100). Under a set of conditions A, diagnostic accuracy reflected that of current general practice and 50% of fillings survived up to 5 yr. Under a set B, diagnostic accuracy was that of a trained epidemiologist and 50% of fillings survived up to 10 yr. Assumption A scored 75.3 while B scored 81.9, suggesting scope for added health gain through improvement of practice standards.

Algorithms↗
PubMed1994

Dental caries experience and defects of dental enamel among 12-year-old children in north London, Edinburgh, Glasgow and Dublin.

A multi-center study of caries experience and defects of dental enamel was conducted among 12-yr-old children in north London, Edinburgh, Glasgow and Dublin. None of the cities had water fluoridation except Dublin, which was included in the national program introduced in the Republic of Ireland in 1964. A random sample of children was drawn from state schools in each location and identical methods of clinical examination were used throughout under the same standardized conditions. All examiners were trained and calibrated with a reference examiner and achieved high levels of inter- and intra-examiner consistency. Mean DMFT values for the 4 cities were 1.27 (London), 1.39 (Edinburgh), 2.70 (Glasgow) and 1.48 (Dublin) (P < 0.001). Proportions of subjects free from caries in the same order were, 50, 47, 24 and 43% (P < 0.001), and child prevalence of diffuse opacities, 28, 29, 7 and 17% (P < 0.001), respectively. The relatively low caries levels recorded in London and Edinburgh (lower than Dublin) were considered to be related most probably to fluoride effects other than water fluoridation.

Analysis of Variance↗
PubMed1994

Caries prevalence in the United Kingdom.

Since 1973, national surveys of dental caries in children, one series directed decennially by the Office of Population Censuses and Surveys and another, using analogous methods, coordinated regionally on a regular basis by the British Association for the Study of Community Dentistry, have produced a comprehensive record of trends in caries experience of children in England and Wales. Between 1973 and 1993 a decline in caries experience of 55 per cent in deciduous teeth of 5-year-old children, 75 per cent in permanent teeth of 12-year-old, and 74 per cent in 14-year-old children, was documented. However, the most recent surveys, carried out since the end of the 1980s, suggest that caries levels have now levelled out and may even have started to rise in younger children while in adolescents the rate of decline has slowed substantially. Possible explanations for these trends are discussed. The national data conceal wide disparities between different regions of the country and a notable worsening in the caries experience of children in lower socio-economic groups. In order to consolidate the gains of the last 20 years and safeguard the future dental health of both children and adults, implementing population preventive methods such as water fluoridation should be vigorously pursued.

Adolescent↗
PubMed1994

Enamel opacities and dental caries in children who used a low fluoride toothpaste between 2 and 5 years of age.

A recent clinical trial investigated the cariostatic effectiveness of a low (550 ppm) fluoride toothpaste in comparison with a standard (1050 ppm) control paste in pre-school children who were 2-years-old at the start of the 3-year trial. The present study has investigated the prevalence of enamel opacities in permanent incisor teeth and of caries in children who had taken part. As well as children from test and control groups, a third group of non-trial children were included in the sample. A total of 1,523 children were examined in schools and had photographs taken of their upper permanent incisor teeth. The latter were scored using the Thylstrup and Fejerskov (TF) index for fluorosis and the modified Developmental Defects of Enamel (DDE) index. Differences between the groups were small in real terms but using the TF index the child and tooth prevalence of opacities were significantly lower in the children who had used the test paste with a lower fluoride content; the same trend was seen in diffuse defects scored using the modified DDE index. There was no significant difference in the prevalence of caries in either primary or permanent teeth although the trend in both cases was for slightly more disease in children who had used the test paste.

Cariostatic Agents↗
PubMed1993

Changing trends in dental caries experience in Great Britain.

Periodic national surveys of dental health since 1968, and a coordinated program of local surveys of children since 1985, have provided a comprehensive picture of trends in dental caries experience in Great Britain over the course of two decades. This review of some of the findings examines changes in adult caries experience, together with the related phenomenon of total tooth loss; presents evidence of a cohort effect in the decline in caries among children and young adults; and considers likely future trends and their implications for the dental services. Conclusions drawn were: (1) Although the proportion of the population with no natural teeth is declining rapidly among young adults, levels of edentulousness among older age groups will remain high for some time to come; (2) in England and Wales, a modest decline in caries experience of young adults between 1968 and 1978 accelerated between 1978 and 1988 [The greatest change in annual rate of reduction over two decades was in 16-24-year-olds, and in absolute terms, mean DMFT in this age group decreased from 15.7 to 10.4 during the period.]; (3) a cohort effect is discernible in the changing pattern [Thus, caries has apparently stabilized in young children, whereas in adolescents and young adults the rate of decline has increased.]; and (4) smaller improvements in dental health have occurred in Scotland than in England and Wales.

Adolescent↗