Optimal conditions for the use of cDNA probes to measure the concentration of barley yellow dwarf virus in barley (Hordeum vulgare).

Experiments which optimise the conditions for the measurement of the relative concentration of BYDV in barley (Hordeum vulgare) tissues using cDNA probes are described herein. These studies have shown that both the pH of the buffer and the ratio of buffer to tissue used to homogenise plant material greatly affects the amount of cDNA probe which hybridises to leaf extracts immobilised on nitrocellulose. These studies also showed that the measurement of this virus was greatly facilitated by using a dot-blot apparatus which allows samples contact with a piece of nitrocellulose 10 mm in diameter rather than a 3 mm (approx) diameter piece of nitrocellulose as is the case with most commercial dot-blot apparatuses. Further experiments using this technique showed that there was a large difference in the rate of replication of the PAV, BYDV serotype between BYDV-resistant and BYDV-susceptible cultivars of barley. These data suggest that a BYDV-resistant cultivar can easily be distinguished from a BYDV-susceptible one if the BYDV content of leaves is measured between 7 and 14 days after inoculation.

Cost appraisal of a fluoride tablet programme to Manchester primary schoolchildren.

The Manchester fluoride tablet trial was a pragmatic study to assist the Health Authority to decide whether to provide fluoride tablets daily to all primary schoolchildren in the District prior to water fluoridation being introduced. Twenty-two primary schools took part, half being allocated at random to the public health programme while the other half remained untreated. The average age at baseline was 5 yr 3 months. Costs were monitored throughout the trial and tangible and intangible benefits assessed. 263 children in the test schools and 266 in the control schools completed the trial. The cost per child was 4.39 pounds for the 3 yr of the trial. Economies resulting from an increase in size of a substantive scheme were estimated producing a cost of 1.98 pounds/child over a 3-yr period for a tangible benefit of 3.23 pounds. In addition, the intangible benefits of less anxiety, less treatment, and fewer experiences of general anaesthesia need consideration.

Combined effects of a fluoride dentifrice and mouthrinse on the incidence of dental caries.

751 14- and 15-year old children completed a 3-year, double-blind, caries preventive program. The effects of daily, supervised toothbrushing with an 0.76% sodium monofluorophosphate dentifrice, rinsing with a 0.05% sodium fluoride mouthrinse, and the combined effects of the two treatments were investigated. Both the dentifrice and mouthrinse reduced the incidence of dental caries, but their combined use at the same time had no greater effect than either used alone.

The relationship between restorative treatment provided and a one year increment of the F component in the DMF index.

There is considerable debate over the estimate of true increment of caries in an adult population derived from a conventional epidemiological study. The purpose of this investigation was to compare the increment of restorative treatment provided by dentists for caries with an estimate of what would have been recorded in a conventional epidemiological study as FT(S). The two types of increment were calculated from data collected for 3,920 regularly attending adults over the age of 25 years receiving dental treatment from 24 general dental practitioners. The adults were treated by their dentists prior to baseline so that, in the dentists' opinions, there were no caries lesions requiring restoration. All treatment carried out over the next 12 months together with the reasons for this, were recorded by the dentists. The increments for all restorative treatments and those considered by the dentist to be related to caries were calculated and compared with the conventional epidemiological FT and FS increments, calculated as changes from sound at baseline to restored for both teeth and surfaces. The results showed that the epidemiological FT and FS increments under-estimated both the total restorative treatment and that provided for caries by the dentists.

Factors of deprivation associated with dental caries in young children.

Quantitative and qualitative data were collected on the communities in the Tameside and Glossop Health Authority district served by the five primary schools with the highest prevalences of dental caries among their 5-year-old children and contrasted with similar information from communities served by five schools whose 5-year-old pupils had the lowest prevalences of caries. Quantitative data were collected from a variety of sources including the health and education authorities, and qualitative information was gathered by interviewing health and education personnel with special knowledge of the primary and pre-school children involved. It was found that communities with a high caries activity among their primary school children had lower proportions of babies of normal birth weight and uptake of poliomyelitis vaccination, while more children were born to single parent families. They also had lower percentages of private housing, homes with a car and households in social classes 1 and 2. The high caries schools had more children receiving clothing allowances and free school meals. The communities they served had higher Townsend mean deprivation Z scores and lower percentages of crime rates per household. The high caries communities tended to bottle feed their babies, wean them earlier, use infant feeding bottles longer and give babies fruit juices more regularly. The parents in the high caries communities were reported to have higher proportions of social and financial problems, were less likely to form parent-teacher associations, their children had poorer attendance and punctuality records, worse behaviour and greater consumption of confectionery after school.(ABSTRACT TRUNCATED AT 250 WORDS)

An evaluation of the role of health visitors in encouraging dental attendance of infants.

A dental health campaign which aimed to increase the number of infants registered under capitation with general dental practitioners took place in the North Western Region. The aim of this study was to evaluate the effectiveness of health visitors in encouraging dental attendance of this age group. Facilitators in each of the 7 districts involved worked with general dental practitioners and health visitors to ensure referred infants were accepted. Health visitors completed a data collection form with each referral so that the names could be checked for subsequent registrations. Parents of 3,165 children were contacted between January and May 1991. Of those 76 per cent (2,412) were referred to general dental practitioners, but only 21 per cent of those names that could be checked were traced to dentists' lists by the end of the study period. Only 40 per cent of those claimed to be registered could be identified. Most dentists said they would welcome further campaigns to increase attendance of infants. Health visitors agreed that early referrals were appropriate, and this campaign may have contributed to the high number of registrations of 0-2-year-olds in the North Western Region.

Factors affecting dental attendance among school leavers and young workers in Greater Manchester.

The aim of this study was to investigate those factors which could influence adolescents in their dental attendance habits. Discussion groups were formed with school pupils in their final school year and with Youth Training Scheme trainees who had been working for six months or more. Fourteen discussions, involving 97 adolescents, were carried out and recorded on tape. Analysis of these tapes permitted comparison of the responses of the school leavers and the trainees which revealed some recurring themes. No major differences were found between the adolescents in their views on dental attendance before and after leaving school. Many respondents said that they had been able to decide for themselves about going to the dentist since they were 12, 13 or 14 years old, well before school leaving time. A low perception of need and a high level of confidence in self-care were widely reported and these tended to reduce the likelihood of attendance. The desire to maintain or produce a good dental appearance was frequently given as the main motive for attending the dentist.

The prevalence, causes and cosmetic importance of dental fluorosis in the United Kingdom: a review.

OBJECTIVES: To determine the prevalence of fluorosis and other developmental defects of enamel (DDE) in the United Kingdom over the last 40 years. To examine the risk factors that may have influenced the prevalence of fluorosis. DESIGN: All relevant publications between 1956-1995 on the prevalences of DDE and fluorosis in the UK were critically reviewed in addition to publications from other countries where these added substantial information about the risk factors involved in the latter. RESULTS: The likely overall prevalence of DDE in the UK is approximately 40 per cent of which diffuse opacities account for about half. In areas benefiting from water fluoridation the overall prevalence of DDE is around 70 per cent with diffuse opacities accounting for two thirds. No substantial evidence of increases in either DDE or fluorosis could be identified. Risk factors for fluorosis include inappropriate use of fluoride supplements and fluoride toothpaste during early childhood and life-time residence in an optimally fluoridated area. CONCLUSIONS: Fluorosis does not appear to be of public health concern in the UK at present. However, the inadequacies of the data and paucity of in-depth studies highlight the need for further co-ordinated research using agreed methods of monitoring prevalence, multivariate analysis to identify risk factors and a societal norm to discover its cosmetic impact.

A novel school dental screening programme.

The study validated a novel school dental screening test based on the professional and public belief that regular, or asymptomatic dental attendance is beneficial to oral health. A randomly selected group of 175, 14-15-year-old boys and girls were questioned about their dental attendance which was verified either by the dentists whom they claimed to visit or by further questioning those whose behaviour was not clear. This method of separating symptomatic from asymptomatic attenders had a sensitivity of 1.00 and a specificity of 0.72. The method was inexpensive and acceptable to both the school staff and the pupils. The preventive dental knowledge of both groups was high. Although the dental attitudes of the asymptomatic attenders were significantly better than those who attended symptomatically it was not possible to demonstrate with confidence that they had better dental health.

Adult dental surveys: a different approach.

Traditional surveys of adult dental health have used calibrated examiners to collect clinical data. This study examines an alternative approach using data collected by general dental practitioners about their adult patients. Twenty-four dentists in Greater Manchester recorded both personal and intra-oral information on 3,832 of their regularly attending dentate patients over 24 years of age. The mean numbers of filled teeth, sound teeth and the proportion of patients with 21 or more teeth were all similar to those found in the 1988 United Kingdom national survey of adult dental health. For example, the mean number of filled teeth in the 25-34 year age group was 11.7 compared with 11.9 for subjects who claimed to attend regularly in the 1988 national survey, and these figures reduced to 11.2 and 10.0 in the 55-64 year age group. The proportion of adults with 21 or more teeth was found to be 99 per cent compared with 98 per cent in the 1988 survey for the 25-34 year age group, falling to 55 per cent compared with 56 per cent in the 55-64 year age group. The collection of epidemiological data by general dental practitioners is feasible, and has construct and internal validity. It is a possible alternative to conventional surveys of adult dental health.

Dental health status associated with documented dental attendance patterns in adolescents.

OBJECTIVE: To investigate the dental health of adolescents who exhibited four different patterns of documented dental attendance in regard to caries experience and types of treatment they received. DESIGN: The adolescents were categorised according to whether they had been asymptomatic or symptomatic attenders in childhood and whether this had changed in early adolescence. Asymptomatic attenders were those who attended for examinations at least twice in any three year period. Symptomatic attenders were those who attended for examinations less frequently than this. SUBJECTS: Treatment notes of 254, 13-15-year-old subjects who reported they were patients at one of 12 general dental practices or two community clinics were used to document attendance during the previous six years. RESULTS: Those who attended asymptomatically throughout the study period of six years had fewer teeth extracted and more sealed teeth than those who attended symptomatically. CONCLUSIONS: Among adolescents dental attendance in the absence of symptoms is associated with fewer missing teeth and wider provision of fissure sealants.

Development of a classification and index of dental treatment experience for adults.

OBJECTIVE: To develop and evaluate a classification and index of dental treatment experience for adults. DESIGN: Twenty-four general dental practitioners recorded treatment experience at baseline on 4,211 regularly attending adults of whom 3,878 were re-examined after one year and 3,698 patients completed a questionnaire on factors related to treatment. SETTING: Health authorities of Manchester and Salford. METHOD: Set theory was used to divide the baseline clinical data set into 7 mutually exclusive classes of dental treatment experience. Seven dental specialists used the nominal group technique to weight tooth status to form an index of dental treatment experience (DTE). The ability of the DTE classification and index to discriminate between groups of patients' responses to the questionnaire was compared with the THI and DMFT index. RESULTS: Ninety-nine per cent of the patients fell into 5 hierarchical classes ranging from fillings only to wearing a denture in addition to a crown and/or bridge. When calculated on the baseline data, the classification discriminated between 16 of the 20 variables investigated in the questionnaire. Fifteen significant differences were found between mean scores for groups of patients on the DTE index, 14 on the THI and 8 on the DMFT index. Fifty-five (1%) patients moved their class as a consequence of the treatment carried out during the year. All three indices found significant differences for the same four variables of the 20 tested. CONCLUSION: A classification of dental treatment experience together with an index to measure the severity of that experience has been successfully developed and tested. It appears to have advantages over the traditional DMFT index and is at least as discriminating as the THI.

An assessment of capitation in the new General Dental Service contract.

A 2-year study has been completed to examine the dental health and patterns of treatment of samples of children registered under capitation in three areas of England. The opportunity was taken to compare some of these results with those reported in the same areas in 1989 when the dentists were remunerated under fee-for-service. In addition, the validity of the dental health information supplied by general dental practitioners on the FP17C form was assessed. The dental health of 14-15-year-old patients registered for more than a year was compared with that of similar patients in the same areas in 1989. There was a large reduction in the caries experience (mean DMFT) in these patients in all areas between 1989 and 1994 mainly due to a significant fall in the mean numbers of teeth filled. The mean number of teeth extracted for caries remained low in all areas. There was a small increase in the mean number of decayed, untreated teeth in all areas. There was a large increase in the proportion of patients with one or more fissure sealants present. The dental health of 7-8-year-old patients registered for more than a year was examined but, as this age group were not examined in 1989, no comparative data were available. Regularly attending child patients had, on average, one untreated decayed deciduous tooth, but few had more than two. Caries experience in first permanent molars was low in all areas. Data were collected from a sample of general dental practitioners in three areas on the treatment provided over a 12-month period for random samples of patients in two age groups: 6-12 and 13-15 years. There was an increase in two of the three areas in the provision of oral hygiene instruction and dietary advice. The level of fissure sealant use was maintained or increased. There was a reduction in the numbers of both deciduous and permanent teeth filled. Fewer children had teeth extracted. The proportions of patients having bitewing radiography reduced. The mean number of both visits and check-up examinations reduced. There validation of the dental health information on the FP17C was carried out by comparing the data collected for 7-8 and 14-15 year old patients during the dental health examinations with that submitted by general dental practitioners on FP17C forms to the Dental Practice Board for the same children. For the permanent dentition, agreement was good for missing and filled teeth but poor for decayed, untreated teeth. For deciduous teeth, levels of agreement were generally poor except for filled teeth where it was fair.

A trial of a capitation system of payment for the treatment of children in the General Dental Service. Final report. Dental Health Services Research Unit, University of Manchester. September, 1989.

A 3-year clinical trial comparing capitation and fee-for-service remuneration systems for general dental practitioners for the treatment of children has been successfully completed. Capitation dentists restored carious teeth at a later stage in the disease process than fee-for-service controls, and carried out more preventive treatment and advice. However, the disease experience of their patients was little different from that of patients treated under fee-for-service. Capitation dentists saw their patients less frequently and took fewer radiographs than their fee-for-service colleagues. The prevalence of both fissue sealants and arrested caries was low in both groups, as was the prevalence of teeth extracted as a result of caries. Levels of oral cleanliness were similar under both systems. Private treatment was rarely prescribed for children, but was more prevalent for patients of fee-for-service dentists. The profession felt that capitation offered greater clinical freedom and more financial stability to dentists, but a greater temptation to under-prescribe treatment. The profession lacked commitment to capitation as a method of remuneration for the treatment of children in the General Dental Service. Fee-for-service dentists appeared to be more innovative, expressed a greater allegiance to their patients and felt a greater temptation to over-prescribe than capitation dentists. The parents had a high opinion of the service for children, irrespective of the remuneration system, and the children found the service very acceptable. Parents had a stronger allegiance to the fee-for-service than the capitation dentists. The study revealed several short-comings in the capitation model tested, but solutions to all of these became apparent. A capitation agreement of more than 12 months would simplify administration and reduce costs, as would a reduction in the number of forms. The need to notify parents when a dentist was replaced in a practice created considerable difficulties and increased expense. The treatment of trauma and extractions for orthodontic purposes should have been items excluded from the capitation fee. The need for information on dentists' activity in capitation was accepted but should be kept simple and relevant. Monitoring quality of care under capitation can be carried out from the routine data collected for administrative purposes. Capitation does not appear to increase participation. Costs of administering capitation are little different from those for fee-for-service. More resources were spent per dentist and per patient under capitation than fee-for-service. In the clinical trial fee-for-service was more cost-effective than capitation.(ABSTRACT TRUNCATED AT 400 WORDS)

The success of restorative dentistry?

Direct statistical evidence of the value of routine, periodic dental examination and treatment is lacking and inferences can only be drawn from surveys of population samples and groups of people. Except perhaps in areas of exceptionally favourable dentist: population ratios the restorative philosophy makes too high a demand on scarce professional resources for it to answer the treatment needs of populations. However, it was originally developed to benefit individual patients who sought dental care and the evidence at present suggests that it may postpone the loss of teeth. It is hypothesized that the restorative philosophy is palliative rather than remedial.

Cost: benefit of prevention in practice.

An enquiry among 50 successful, general dental practitioners working under a capitation payment system for the treatment of children, showed that they all thought that prevention on selected patients was of value to their practice. They said that prevention enhances the reputation of the practice, adds to the job satisfaction of the dentist and is part of modern dental philosophy. However, only when practised selectively would it be cost: beneficial. The most popular preventive treatments were fissure sealants, particularly when used on selected patients, oral hygiene demonstrations and, among a group of enthusiastic dentists, dietary counselling. Dentists who employed hygienists had a significantly higher 'mean preventive awareness score' than those who did not.

The benefit of preventive procedures for high risk groups.

The clinical effectiveness of many caries prophylactic agents has been demonstrated but their public health value questioned from the viewpoint of economic efficiency. However, some groups within the population may have enhanced response to certain agents and for these subjects a more acceptable cost-value situation may occur. The effectiveness of agents may be measured by the extent to which they reduce operative treatment need. Therefore by costing treatment carried out in both groups in a clinical trial and adding, for the test group, the cost of prevention, the cost effectiveness of treatment plus prevention compared with treatment alone can be investigated. A computer was programmed to estimate from DMFS data, maintenance treatment carried out during clinical trials and that needed at the end to render subjects free of caries. Treatment was costed on the Resource Related Index. In an examination of two experimental clinical trials among adolescents it was found that supervised daily brushing in school with MFP dentifrice produced a 25 per cent reduction in DMFS over three years, but cost six and a half times as much as the operative treatment saved. However, for a high risk group of girls the cost was only two and a half times as much. When APF topical applications by hygienists were added to the same brushing programme it became even less economically efficient. Neither experimental programme was cost-effective for any group unless a weighting factor was introduced to take account of the desirablity of a sound as opposed to a filled tooth.

The value of self-applied fluorides at home.

Dental research workers from several scientific disciplines have combined over the years to give much greater insight into the basic mechanisms whereby fluoride protects the teeth against dental decay. These basic investigations have enabled clinical research workers to test new fluoride delivery systems rationally rather than empirically, and it now seems that two entirely different modes need to be combined to form maximum protection. First, fluoride ions need to be introduced at the correct level into the forming enamel crystals during tooth development; secondly, fluoride ions need to be present at optimal concentrations at the plague-enamel interface during active carious attack. Both these situations require low levels of fluoride concentration to be delivered to the subject at very regular intervals. Water fluoridation is the best method of achieving this situation, but in the absence of this important public health measure, dental scientists have developed a battery of other vehicles which, when used on a daily basis at home, will have a considerable impact on caries activity. While further work continues to improve the effectiveness of these techniques, enough has been achieved already to encourage their use by the general public. What are required now are the necessary skills in health politics and behavioral science to gain public acceptance and application of these endeavours.

The Danish oral health care service for children: an evaluation.

An evaluation of the children's oral health care service was performed by an international assessment team who undertook a field programme in Denmark. Three counties were visited, one metropolitan, one urban and one rural. Data on dental health costs were collected and dental services in six municipalities selected at random were examined. Opinions of administrators at all levels and those of clients and providers were obtained and interviews also took place with staff and students at the two dental schools. The service was considered effective insofar as active dental disease was closely controlled by restorative care and a high level of dental awareness was instilled in all sections of the child population. The service was also clearly adequate since participation of schoolchildren was almost universal. However, resource expenditure on both professional personnel and clinical facilities was considered high and the efficiency of the service was possibly rendered less than optimal by a degree of over-provision in 'passive' prevention and orthodontics. The appropriateness of devoting so much resource to children at the expense of the population as a whole was also regarded as questionable as was the lack of a fluoridation programme. Client groups wholeheartedly supported the service as a result of the high quality of care and the attractive, considerate image projected by clinics and staff. The overall excellence of the service was a matter of satisfaction to administrators, of gratification to clients and of pride to the providers whose morale was high.

The Danish oral health care service for children: an international appraisal.

The Danish children's oral health care service has been so successful in achieving its objectives that it will need to change and adapt in order to survive. It is suggested that the service should gradually become community-based rather than child-based. This process can be commenced by introducing treatment for the elderly, the handicapped and the indigent, converting the school clinics to municipal oral health units. Although it is important that private practice is maintained, private dentists should be encouraged to work in the system part-time, leading teams of supporting auxiliary personnel trained within an integrated system. Eventually, the facilities could form the basis of primary health care centres. The lessons to be learnt from the Danish experience have a wider application to other countries. In developing countries it is obvious that they should first place limited dental resources into public health prevention and only invest in expensive treatment clinics as funds become more available. Manpower planning should ensure that personnel are not overtrained for the needs of the community. In developed countries, increasingly more resources will need to be channelled into adult dental care, and dental education must lead the profession into this new era. Difficult though these changes will be, the stable relationships that have developed between the various arms of the service under the guidance of the Danish Dental Association, will ensure that the profession will survive and flourish for the benefit of the Danish people.