9.8 Dental public health
Oxford Textbook of Public Health
Dental public health
Stanley Gelbier and Peter G. Robinson
The importance of oral health
Impacts of oral disease
Frequency of oral disease
Implications of changes in caries prevalence
Oral health promotion
The use of fluoride
Prevention of accidents
Ensuring access to appropriate preventive care
Focus on prevention
Conclusions and future developments in dental public health
Under a variety of guises dental public health has come to the fore in developed and developing countries. The British Association for the Study of Community Dentistry defines dental public health as: ‘the science and the art of preventing oral diseases, promoting oral health and improving the quality of life through the organized efforts of society’. In the United Kingdom, it has become very sophisticated, there now being a recognized speciality of dental public health. The areas which are perceived to be the business of British consultants and specialists in dental public health include:
indicators of oral health
determinants of oral health status
evaluation of oral health services
prevention and control of oral disease
promotion of oral health
policy and service development and prioritization
evaluation of technology
the effectiveness of treatment modalities
promotion of clinical effectiveness
Although defining the United Kingdom situation, these areas are of relevance worldwide. They also help to provide cost and clinically effective services.
In order to be prepared to undertake such specialized work, specialist registrars in the United Kingdom undertake a period of education and training. Before entry to the training programme, candidates must possess a fellowship or membership in dental surgery of one of the Royal Surgical Colleges (England, Edinburgh, Glasgow, or Ireland). They also gain a Master of Science degree in dental public health (or its equivalent), either before or during the training period. The training programme takes place under the direction of an established consultant in the specialty. During training they are expected to demonstrate the acquisition of a number of distinctive competencies, which will enable them to undertake their work. These competencies have been divided by the specialty into the eight areas listed below. All have relevance in both developing and developed countries, although the emphasis on particular components will vary according to social factors, the burden of disease, organization of health services, geographical factors, and the economy.
Oral health needs and demands assessment: description of the determinants of oral disease; identification of determinants amenable to change; understanding the principles of epidemiology and biostatistics in relation to dentistry; derivation of appropriate dental indicators; survey and database design; and data analysis including interpretation of statistics and application of results.
Information technology, commissioning, and evaluation of dental health services: knowledge of the availability and methods of access to various sources of information within the health service; understanding the contracting processes through which health services are purchased and monitored; contracting and service specification development to meet dental health needs; derivation and measures of oral health improvement and application of appropriate economic analysis.
Promoting oral health: ability to interpret oral health and dental practice in terms of social relationships and social context; understanding of the principles, methods, and limitations of preventive dentistry and oral health promotion.
Research and development: identification of appropriate areas for research and development and the application to this of research methodology.
Teaching and training: at undergraduate and postgraduate level and in multidisciplinary/multiagency settings.
Effective communication: negotiation; influencing; communication (written, oral, and non-verbal); listening; counselling.
Management: resource management, control, leadership, planning, conflict management, team work/co-ordination, organization.
Political acumen: developing policy, political awareness (the art of the possible), evaluating strategy, strategic opportunism.
In the subsequent sections we shall show how some of these areas are used in everyday practice.
The importance of oral health
Oral health is often a low priority for individuals, policy-makers, and public health specialists. In fact, oral health is an important public health problem because oral diseases have significant impacts on individuals and the community, they are widespread, and the two most common diseases—tooth decay (dental caries) and gum (periodontal) diseases—are almost entirely preventable.
The impacts of oral disease range between frank mortality and effects on systemic health and quality of life. Oral diseases also create a considerable burden to both individuals and the community in terms of economic productivity.
Impacts of oral disease
Mortality from oral cancer is related to the site in the mouth and the timing of the diagnosis but 5-year survival is less than 50 per cent. In addition to mortality, oral disease affects other aspects of systemic health. Limited dietary choice and calorific and micronutrient intake are direct consequences of conditions such as xerostomia, poorly fitting dentures, loss of teeth in nursing caries, and oral developmental disorders (Hollister and Weintraub 1993). The role of bacteraemia as a sequel of oral disease and treatment is well known in the aetiology of bacterial endocarditis but periodontal diseases may also be aetiological factors for cardiovascular disease and low birth weight.
Oral diseases also directly affect our quality of life (Slade 1997). Dental pain is very common. As many as one in eight adults in the United States experience toothache over a 6-month period and still more have sore mouths and joint pains (Lipton et al. 1993). One in six 8-year-olds in a suburb of London had experienced toothache which had caused them to cry (Shepherd et al. 1999). Oral appearance affects our self-esteem, our willingness to interact with others, and influences the judgements other people make about us (Shaw et al. 1985; Fiske and Waters 1990). Good dental appearance is regarded as a requirement for some prestigious occupations (Jenny and Proshek 1986).
The economic costs of dental disease are difficult to calculate. As well as the direct costs of disease and treatment, there are indirect costs which might include reduced employment or promotion expectations and opportunities, limitation of academic achievement, and the total societal burden through loss of economic productivity. The direct costs are between 0.2 and 1 per cent of the gross national product in developed countries (van Amerongen et al. 1993). The United Kingdom is at the lower end of this range. Yet dentists’ fees for treatment within the National Health Service (NHS) in England and Wales (population 52 million) for the first 3 months of 1999 were £357 million (equivalent to £1.4 billion per annum) and the figure is rising each year (Dental Practice Board 1999). This sum is all the more surprising when it is considered that only 18 million of the population are registered with an NHS dentist. The cost of treatment provided outside the NHS is not known. An indication of the loss of economic productivity due to dental disease was calculated by Gift et al. (1992). In 1989, over 20 million work days and 51 million school hours were lost in the United States due to oral disease and its treatment. These data equate to 1.5 h for each employee annually. Low-income families were more likely to lose time from work and school because of dental disease and so these impacts of oral disease compound the inequalities that already exist in health, income, and educational attainment.
Frequency of oral disease
Oropharyngeal cancers are amongst the 10 most common cancers in the world and their incidence is increasing. The highest reported incidence rates are in India and Sri Lanka where the mouth is the most common site, comprising up to 40 per cent of all cancers. Despite falls in incidence of dental caries over the last three decades, 45 per cent of 5-year-olds in Great Britain have evidence of clinically significant tooth decay (Pitts and Palmer 1995). Periodontal diseases are even more common. More than 80 per cent of adults have inflamed gums (gingivitis) and most have evidence of destruction of the attachment between tooth and bone (periodontitis) (Brown et al. 1989; Todd and Lader 1991).
Finally, the two most common oral diseases are almost entirely preventable. Clinically significant dental caries occurs only in the presence of excess dietary sugar. Estimates suggest that the incidence of disease could be kept acceptably low at levels of sugar consumption below 10 to 15 kg/person/year (Sheiham 1991). This dietary control of tooth decay can be supplemented by the use of fluorides which demonstrably prevent the disease whether presented in drinking water or in toothpastes. Likewise, the presence of dental plaque is necessary for the most common form of destructive periodontal disease. Targets for oral cleanliness have been calculated which appear to be compatible with freedom from periodontal disease throughout life (Burt et al. 1985). Slightly higher levels of plaque might be compatible with acceptably low levels of periodontal disease.
Therefore oral health therefore has a public health significance. This chapter will discuss the features, epidemiology, aetiology, and management of four important oral diseases: dental caries, periodontal diseases, oral cancer, and orofacial trauma. Approaches to oral health promotion in relation to these diseases will be outlined within a common risk factor approach.
Under normal circumstances, there is a chemical equilibrium between the minerals of the tooth and the adjacent oral fluids. The equilibrium is disrupted by acidic metabolites of oral bacteria if there is an excess of dietary sugars. Dental caries is the progressive demineralization of the tooth that results. In the very early stages, the lesion appears as a chalky white spot on the teeth. If the lesion progresses, the surface of the tooth breaks down and there is cavitation. If the caries reaches the underlying dentine, it can spread more readily through the porous and less mineralized tissue toward the pulp. Infection of the pulp may allow the passage of bacteria along the root canals to the alveolar bone.
The direct consequences of this process are destruction of the tooth, pain, and a possible dental abscess. Dentine is sensitive to physical, thermal, and osmotic stimuli. When it is exposed by cavitation there may be transient pain associated with hot or cold drinks or sweet foods. Later, as the pulp becomes inflamed, the discomfort may be spontaneous, exquisitely painful, and of longer duration. In a dental abscess, pressure to the tooth is transmitted to the infected alveolus and the unfortunate person avoids biting or knocking the tooth.
Four factors are necessary for the development of caries: dietary sugars, a susceptible tooth surface, the microflora of dental plaque, and adequate time.
Despite the obvious ethical difficulties of conducting human experimental studies to investigate the role of sugars in the aetiology of dental caries, the evidence implicating them is more than compelling. Rugg-Gunn’s (1993) encyclopaedic review classifies this evidence methodologically into human observational studies, human interventional studies, animal experiments, enamel slab experiments, plaque pH studies, and incubation experiments. Dietary sugars are essential if the caries is to be of clinical relevance. The bacteria of dental plaque, particularly Streptococcus mutans, metabolize them and so produce acids and use them to form extracellular polysaccharrides. The polysaccharides increase the bulk of the plaque, facilitate the adhesion of more bacteria, and restrict the flow of saliva to the tooth surface. With each exposure to sugar the plaque pH falls sharply and rises slowly back to normal levels over the following hours. It follows that caries incidence is related to the frequency of intake of sugars (Gustaffson et al. 1954).
The mineral component of the tooth is predominantly calcium and phoshate in the form of hydroxyapatite. At normal pH levels, the hydroxyapatite crystals of tooth are in dynamic equilibrium with these ions in the plaque fluid. At high pH there is remineralization of the tooth, especially in the presence of fluoride. Saliva plays a crucial protective role against caries by simple dilution, by buffering plaque acid, and by acting as a source of minerals and chemical and immunological plaque inhibitory factors. For these reasons dental caries is more frequent in the sites less accessible to the saliva—the pits and fissures of posterior teeth and between these teeth. Caries is also more common in people with restricted salivary flow.
Caries of the permanent dentition is traditionally measured using an index which records the number of decayed, missing, and filled teeth. A more precise index records the number of surfaces affected and a similar index is used to record the status of the deciduous dentition. Because the index aggregates both disease and treatment experience it is sensitive to the treatment decisions of dentists and so less valid with increasing age. Since each of the categories is equally weighted, it is insensitive to both the severity of the disease and outcomes of treatment. At low levels of caries the number of people ‘caries free’ (which actually means free from clinical evidence of progressive disease and treatment) may be a more useful community-based measure of disease.
Nonetheless the decayed, missing, and filled teeth index has been used for 60 years and will continue to be used. This does not mean that decayed, missing, and filled teeth index scores of yesteryear are directly comparable with those of today as the criteria for judging a tooth as carious have changed. Although the threshold for diagnosis is usually whether the caries has reached dentine, many previous criteria used a sharp dental probe to determine whether there was cavitation of the tooth (WHO 1979). The criteria now in use in many countries avoid the use of probes to prevent damaging the tooth surface. Consequently, the index is less sensitive and more specific (WHO 1997). However, the dental status of populations is usually summarized by the mean decayed, missing, and filled teeth index of 12-year-old children. Chronological and international comparisons are made with these data.
Although dental caries can be identified in the teeth of skulls found in archaeology, dental caries as it is known today did not emerge until sugar became widely available (Burt 1978). Levels of caries rose during the seventeenth century and reached epidemic proportions in the nineteenth and twentieth centuries. The disease has been exceedingly common in some populations with near universal experience in some generations in many countries. Since systematic data have been collected, the typical pattern has been one of high levels of caries in developed countries associated with exposure to sugars. In the mid-1970s levels in many developed countries began to fall dramatically (Marthaler 1990a). In the United Kingdom, the mean decayed, missing, and filled teeth index decreased from 4.8 to 1.2 between 1973 and 1993 and by a similar amount in Australia (4.8 to 1.1) between 1977 and 1993 (Downer 1994; Davies et al. 1997).
This fall in caries incidence in developed countries appears to have halted in the early to mid-1980s (Burt 1994; Downer 1994). The mean decayed, missing, and filled teeth index of 5-year-olds in England and Wales fell from 4.0 to 1.8 between 1973 and 1983 but now appears stable at around 1.8. Despite the halted fall there are cohorts of children and young adults who have better oral health than preceding generations. As these cohorts age there will be commensurate improvements in adult oral health.
Data on caries levels aggregated at the national level provide useful information but can mask important trends. The fall in caries incidence has polarized the inequalities in oral health. In times of high disease prevalence nearly everybody had the disease and the inequalities were manifest merely as differences in the number of teeth affected in an individual. With lower disease prevalence a minority of people carry the burden of most of the disease. Half of all 12-year-olds in England and Wales have never had tooth decay of their permanent teeth (Downer 1994). As is the case for most important diseases, in developed countries dental caries and its consequences are increasingly diseases of the poor (Gratrix and Holloway 1994; Watt and Sheiham 1999).
There have been concerns of increasing levels of caries in developing countries although other analysts suggest that there are no major trends (Holm 1990; Manji and Fejerskov 1990; Fejerskov et al. 1994). Recent surveys in Africa show that caries levels in 12-year-olds are still relatively low although there are suggestions of increases in some countries. Aggregated national data may mask local variations, and in particular, high caries levels in urban areas. Such trends would reflect economic and cultural trends in the region with the change from traditional starchy foods to greater consumption of refined carbohydrates (Thorpe 1993). Of particular concern is the fact that 90 per cent of the caries in Africa remains untreated.
Until the nineteenth century the only useful treatment for dental caries was extraction of the affected tooth. Since then there has been a transition to restorative care in which the infected parts of the tooth are removed and replaced with an inert obdurating filling. During the latter half of the twentieth century technology moved forward, dentists became keen to make use of recent innovations, and patients became willing to pay for them. The result is that operative treatment for adults is increasingly complex and technology intensive. Badly decayed teeth can now be restored with a range of adhesive tooth coloured materials that are either formed in the mouth or prepared in laboratories and then fitted. Originally, missing teeth could only be replaced with removable dentures. Now they can be replaced with bridges which adhere to the remaining teeth or with prostheses supported by osseo-integrated implants which project out through the gingivae.
These treatments provided by dentists might reduce the social impact of dental caries on affected people but play a very minor role in preventing the disease. Dental services explained 3 per cent of the reduction in caries levels in industrialized countries during the 1970s compared with the 65 per cent contribution made by broader socio-economic factors and the availability of fluoride toothpastes (Nadanovsky and Sheiham 1994, 1995).
Implications of changes in caries prevalence
The low incidence of disease experienced in the developed world over the last 15 years has profound implications for the management of dental caries. When the incidence of the disease is low, proportionately more caries affects the accessible occlusal surfaces of the teeth and only simple restorations are needed to treat it (Stamm 1991). The disease also progresses more slowly which allows dentists to defer operative treatment whilst attempting to prevent the spread of the lesion. Many lesions are detected at an earlier stage so that new dental materials can be used in minimally invasive techniques (Elderton 1990).
The lower levels of disease mean that the costs of some dental services might be reduced by reducing the number of interventions and the number of dentists. Increasing the intervals between dental examinations is safe and effective for children and adults with low disease incidence (Riordan 1997). Since most of the restorations required by children are relatively simple, the number and costs of dentists can be reduced by using less highly trained auxiliaries. The reduced burden of disease may allow general dental practitioners to become more involved in health promotion, and to place a greater emphasis on prevention and on quality (Rear 1994). Elderton (1994) has argued for a reduced emphasis on operative technique in dental training so that dentists can become more like physicians working with a range of auxiliaries to obtain the maximum health gain for populations. Conversely, there are still many older people (in this case that means more than around 35 years of age!) who have suffered the ravages of dental caries and its treatment. These people will continue to need and demand increasingly complex treatment for the next 25 years or so (Treasure and Whyman 1995).
Periodontal diseases comprise a range of inflammatory diseases of the periodontium categorized by the position of attachment between gingiva and tooth (Caton 1989). In gingivitis the attachment remains in a healthy position near the cement–enamel junction. Periodontitis is defined by migration of the epithelium which reduces the amount of periodontal ligament and bone supporting the tooth.
Gingivitis is an inflammatory response to plaque. Along with redness and swelling, the gums may bleed on gentle provocation such as cleaning the teeth. Pain is an uncommon feature. Systemic involvement including hormonal changes, skin diseases, and medication use may modify these diseases or cause other gingival changes. The disease is exceedingly common. Bleeding on probing is present in 79 per cent of adults in the United Kingdom and 85 per cent in the United States (Brown et al. 1989; Todd and Lader 1991). Erythematous changes are likely to be more frequent.
In periodontitis the loss of periodontal attachment is manifest by deepening of the pockets between the gingivae and teeth and by recession of the gingivae. In severe cases, the supporting structures are so depleted that the teeth become loose. The disease is rarely, if ever, painful unless an acute infection complicates a periodontal pocket (‘a lateral periodontal abscess’) or if the exposed root surfaces are temperature sensitive.
Sophisticated classificatory systems categorize periodontitis by its age of onset and systemic involvement (Caton 1989), but adult periodontitis is by far the most common form. Its frequency is difficult to assess. The ‘burst theories’ suggest that there are episodes of localized destructive disease followed by quiescence (Socransky et al. 1984). In this case lost periodontal attachment may be the legacy of previous disease and more sophisticated tests are required to detect ‘active’ disease.
Mild periodontal pocketing is common. For example, it is seen in half or more of adults in the United Kingdom and the United States (Brown et al. 1989; Todd and Lader 1991). Evidence of severe periodontitis is much less frequent. Lost attachment or pockets of 6 mm or more (thought to be sufficient to threaten tooth survival) are seen in less than 8 per cent of adults in the United States and the United Kingdom (Miller et al. 1987; Todd and Lader 1991). Evidence of the disease is more frequent and severe in countries where tooth cleaning practices are less sophisticated (Loe et al. 1986).
One other periodontal disease has public health importance. Acute necrotizing ulcerative gingivitis (Vincent’s infection or ‘trenchmouth’) causes necrosis, ulceration, soreness, and bleeding of the gingivae (Johnson and Engel 1986). The ulcerated papillae may have a grey slough and there may be a characteristic fetor. Lymphadenopathy and mild fever are variable findings. In many developed countries, acute necrotizing ulcerative gingivitis is a disease of young adults. There are no good incidence data, but anecdotally it has become less frequent among some developed populations in recent years. A variant of the disease is associated with HIV infection (Robinson et al. 1998). Acute necrotizing ulcerative gingivitis is also seen in African children where it can be progressive in the absence of treatment (Emslie 1963). In severe cases necrosis may extend over adjacent and contiguous tissues to cause gross destruction of oral and facial tissues (known as cancrum oris or noma).
The pathogenesis of periodontitis involves the interaction of plaque pathogens with the host’s immune system (Genco and Slots 1984). Periodontal destruction occurs directly as a result of pathogenic bacterial components and indirectly via host destructive mechanisms that are part of the immune response to infection (Genco 1990).
Dental plaques are consistently implicated in the aetiology of periodontal diseases. Gingivitis is initiated by plaque and reduced by its mechanical and chemical suppression (Silness and Loe 1964; Loe et al. 1965; Loe and Schiott 1970). Plaque is also implicated in periodontitis (Lovdal et al. 1958). Plaque pathogens have virulence factors, including endo- and exotoxins, and initiate and enhance alveolar destruction in animal studies (Gibbons and Socransky 1966; Slots and Genco 1984; Holt et al. 1988). Progression of periodontal destruction is reduced by controlled oral hygiene (Suomi et al. 1971; Axelsson and Lindhe 1978).
Considerable research is devoted to determining which, if any, specific pathogens are responsible for periodontal destruction (the ‘specific plaque hypothesis’). Dental plaque is ubiquitous but destructive disease occurs only in a minority of people. Therefore plaque is not sufficient cause for periodontitis, and microbiological research has diverted attention away from the important determinants of periodontal disease susceptibility (Clarke and Hirsch 1995).
Tobacco use is often confounded by poor oral hygiene in periodontal research, but it is now clear that tobacco exerts an independent deleterious effect (Bergstrom 1989; Ismail et al. 1990; Stoltenberg et al. 1993; Martínez-Canut et al. 1995). In addition, periodontal treatment is less effective in smokers (Preber and Bergstrom 1985, 1990). Stress is also a risk factor in periodontal diseases. Greater occupational stress is associated with progression of periodontitis, and acute necrotizing ulcerative gingivitis has been noted among soldiers on difficult postings, students during examination terms, and people with other negative life events (Roth 1951; Giddon et al. 1963; Linden et al. 1996).
Periodontitis often takes decades to become detectable clinically. Accordingly, it is more common and severe with advanced years because age confounds disease duration (Abdellatif and Burt 1987). Periodontitis is not a consequence of age (Papapanou and Lindhe 1992), it is associated with poor oral hygiene irrespective of age (Suomi et al. 1971), and it does not progress in adults with good oral hygiene (Loe et al. 1978).
In the last few years, periodontal diseases have been linked to a number of other health problems including cardiovascular diseases, stroke, preterm birth, and low birth weight. A number of authors suggest that periodontal diseases may even be independent risk factors for these diseases. Several reports have focused on the biological plausibility of these associations. Periodontal pathogens may invade endothelial cells or periodontal diseases may provide a burden of endotoxins and cytokines which initiate and exacerbate atherogenesis and thrombus formation (Beck et al. 1996; Deshpande et al. 1999).
The main epidemiological evidence supporting links between periodontal and other diseases arises from retrospective analysis of cohort data and from case–control studies (Beck et al. 1996; Offenbacher et al. 1996; Dasanayake 1998). However, there is the potential for misclassification along with other sources of bias in these types of studies. Whilst efforts have been made to control for socio-economic and lifestyle factors, some residual confounding resulting from a failure to account fully for these variables seems inevitable. Specific cardiovascular risk factors such as tobacco use, obesity, and lower serum high-density lipoprotein cholesterol are more common among people with high dental disease experience (Johansson et al. 1994). Some of these factors, such as tobacco smoking, are independent risk factors for both cardiovascular and periodontal diseases whereas others may be linked less directly.
This area of research is exciting periodontal researchers. Large-scale cross-sectional, prospective, and intervention studies to evaluate these possible links are underway. In the meantime no firm conclusions can be drawn (Davenport et al. 1998; Joshipura et al. 1998).
For the majority of people the progression of periodontal destruction is compatible with the retention of a natural dentition into old age. Targets for oral cleanliness have been calculated which appear to be compatible with freedom from periodontal disease throughout life or compatible with acceptably low levels of periodontal disease (Burt et al.1985).
A significant minority of people (perhaps 5–15 per cent) may loose teeth as a result of periodontal diseases, and considerable effort is spent by dentists and dental hygienists attempting to prevent and treat them. Both the prevention and treatment of periodontal diseases focus on the mechanical removal of plaque. Dental professionals attempt to bring this about by instructing patients in the use of toothbrushes and dental floss. Adjunctive services provided by personal dental services include the removal of calcified plaque (calculus) as it may harbour micro-organisms and provide a mechanical barrier to inhibit effective self-care and planing the surfaces of the roots to remove the superficial layers which might be contaminated with bacterial toxins. In some cases the architecture of the periodontium may be surgically adjusted to excise diseased tissue and allow the entry of toothbrush bristles and dental floss into inaccessible areas. In recent times a technique known as guided tissue regeneration has used membranes of synthetic material to prevent epithelial cells proliferating down the root surface after periodontal surgery. This technique allows modest local gains in attachment between the tooth and the underlying periodontium.
A comprehensive review of professionally administered mechanical oral hygiene practices cast considerable doubts on the effectiveness of most interventions commonly employed to treat periodontal diseases (Frandsen 1986). In general, interventions aimed at improving oral hygiene produce only short-term changes which are not sustained (Kay and Locker 1997). Other procedures to treat periodontal diseases, such as the removal of calculus by scaling and polishing, root planing, and removal of plaque at intervals greater than 4 weeks, may not be effective and are harmful in some circumstances. Fourteen million of these interventions are carried out each year in England and Wales alone.
Almost 90 per cent of oral malignancies are squamous cell carcinomas. They may occur on the lip, tongue, gingivae, oral floor, or elsewhere in the mouth. The site is often related to the aetiological factors. Lesions may present as swellings, ulcers, or red or white patches, and many are painless until they become large. Significantly, survival is related to the stage of the disease at presentation. Five-year survival is less than 50 per cent.
Malignant change is often seen in a number of lesions which precede the development of the tumour. These premalignant lesions present as leukoplakias and erythroplakias of unknown origin. Malignant change is also seen, albeit infrequently, in oral lichen planus and hyperplastic candidiasis.
The incidence of oral cancer varies dramatically between and within countries. In England and Wales the incidence is 4.5 per 100 000 which represents approximately 1 per cent of total cancer incidence (OPCS 1994). The highest reported incidence rates are in India and Sri Lanka where the mouth is the most common site and comprises up to 40 per cent of all cancers (Parkin et al. 1992). Men are more susceptible than women in almost all populations independent of the effects of tobacco use (Muscat et al. 1996).
Variations in the incidence of oral malignancy are largely explained by varying exposure to three major risk factors. Cancer of the lower lip is strongly associated with exposure to sunlight, especially in people with fair skin (Lindquist and Teppo 1978). Tobacco use, whether chewed or smoked, predisposes to ntra-oral cancer. The high incidence of oral cancer among southern Asians is largely accounted for by the addition of tobacco to betel quid or paan (Johnson and Warnakalasuriya 1993). There are dose–response relationships for the duration of use and type of tobacco inhaled. Alcohol is also an independent aetiological factor and has a synergistic relationship with tobacco use (Rothman and Keller 1972; Blot 1992).
Since oral cancer is predominantly a disease of older people, it is likely that demographic changes, particularly in developing countries, will see an increased incidence of the disease (Swango 1996). However, age-specific incidence rates in developed countries are relatively stable. A reduction in alcohol consumption combined with the reductions in tobacco smoking already evident in some countries has the potential to make sizeable reduction of the burden of these cancers (Macfarlane et al. 1996).
Because early intervention determines survival in oral cancer, and because many cases are preceded by premalignant lesions, there is a strong argument for case finding as a method of disease control (Platz et al. 1986; Hindle and Nally 1991; Speight et al. 1993). Despite the low prevalence of the disease, screening for oral cancer appears to have acceptable validity. Uptake of screening services is greatest when they are offered in workplace settings (Downer 1997).
Trauma to the teeth is common and frequently causes fracture of the tooth or supporting bone, and bodily movement of the tooth including complete avulsion. In many cases the long-term survival of the tooth is threatened. Since the anterior and most visible teeth are most often involved the result is disfiguring. Approximately one in four teenagers in the United Kingdom have damaged permanent teeth as a result of trauma (Todd and Dodd 1985). The incidence is greatest among young children who have just learnt to walk and among school-age children who may be using bicycles and skateboards (Gelbier 1967). Teenagers and adults who play contact or other vigorous sports are also at risk (Federation Dentaire Internationale 1990). A child’s risk of dental trauma is directly related to the distance that the upper teeth protrude in front of the lower teeth (the overjet) (Todd and Dodd 1985). Primary prevention involves wearing a mouthguard during contact sports such as American football, rugby football, hockey, and boxing. Where possible, play areas for young children should have cushioned surfaces.
Aspects of secondary prevention are crucial for traumatized teeth. Deciduous teeth must be monitored in case any infection occurring as a sequel to the trauma threatens the permanent tooth developing beneath it. In permanent teeth, adhesive fillings can be used to protect sensitive fractured teeth and calcium hydroxide dressings may be placed to allow continued root development in immature teeth. However, the most important aspect of secondary prevention is the first aid of teeth which have been knocked out.
Avulsed teeth can be replaced in the socket (Andreasen and Andreasen 1994). Long-term survival rates of avulsed teeth are high, but are greatest if the tooth is replanted within 30 min to prevent drying, if it is stored in an isotonic medium (e.g. milk) in the interim, if the periodontal ligament is not damaged by physical or chemical cleaning, and if the tooth is held in place by a semi-rigid splint for a week. Systemic antibiotic and antitetanus treatments are required.
The effectiveness of this secondary preventive intervention has two public health implications. Informing athletes and their teachers and trainers of these principles can reduce the impact of dentofacial trauma. The need for almost immediate care means that skilled emergency dental services should be available wherever possible. Unfortunately, dentofacial trauma is not limited to office hours.
Oral health promotion
Since oral diseases are brought about by people’s behaviours, dentistry has traditionally adopted health education as the central thrust of prevention. Toothbrushing and sugar reduction messages have been repeated in both chairside and public education campaigns. However, dental educators have become disillusioned with the recognition that health education cannot readily change these behaviours which are largely determined by our social and cultural environment. Indeed, health education carries its own dangers of disempowerment and victim-blaming and may increase inequalities in oral health (Labonte and Penfold 1981; Schou and Wight 1994).
Closer examination of the causes of oral disorders reveal the potential value of community-based approaches to maintain oral health by acting on the wider determinants of health. Oral disease is brought about by the consumption of sugars, ineffective oral cleaning, tobacco and alcohol use, limited exposure to fluoride, and stress. The common worldwide trend towards widening inequality in economic, social conditions, and health is because the most important non-communicable diseases are determined by lifestyle factors such as these. Therefore the determinants of oral health are the determinants of health in general, and there are many opportunities for wider social and environmental action to play an invaluable role in promoting oral health. There is an increasing recognition that a ‘common-risk factor’ approach is fundamental to the integrated approach to oral health promotion (Sheiham 1992). Collective and multidisciplinary action against factors linked to many diseases reduces duplication, saves resources, and improves effectiveness (Grabauskas 1987).
An additional consideration is that preventive strategies which focus on individuals do not appear to be suitable for dental caries and periodontal diseases since as yet there are no effective ways of identifying which individuals are at high risk of developing the diseases (Rose 1985; Johnson 1991a,b). Whilst individuals at high risk for dental disease cannot be identified with adequate sensitivity and specificity it is possible to identify at-risk populations. In these situations it can be cost-effective to target preventive interventions at people in specific socio-economic groups, attending particular schools, or living in an area with high disease incidence (Burt 1998). However, a strategy of targeted interventions should take place within a common risk factor approach which addresses general health conditions for the whole population. Such an approach will reduce social inequalities and will provide a multiplicity of benefits. It also avoids the limitations inherent in attempting to identify and treat differently those individuals at high risk for disease. Finally, a recognition of the social context in which personal choices are made avoids the social iatrogenesis of describing oral heath in individual terms (Dickson 1995). Dentistry has been quick to adopt approaches which would now be recognized as health promoting. For example, fluoride levels in water supplies were adjusted to prevent dental caries as early as 1945 (Dean et al. 1950).
Health promotion, the process of enabling people to take control over and to improve their health, has five broad actions: creating supportive environments, building healthy public policy, strengthening community action, developing personal skills, and reorienting health services (WHO 1984, 1986). Within this approach Sheiham (1995) suggested six policy areas relevant to oral health:
the use of fluoride
food and health policies to reduce sugar consumption
community approaches to improve body hygiene including oral cleaning
policies on reducing accidents
ensuring access to appropriate preventive care.
This framework will be used in this chapter.
With the growing emphasis on evidence-based health care, oral health promotion must increasingly demonstrate its effectiveness. Recent systematic reviews have aimed to identify oral health promotion practices which yield demonstrable health gains or modified knowledge or behaviours (Brown 1994; Kay and Locker 1996, 1997; Sprod et al. 1996). The principle findings were of a paucity of evidence with few reports of well-designed studies in which the intended outcome was health gain. The most robust studies tended to focus on programmes in which the intended outcome was improved knowledge or modification of the behaviours of individuals. Even these studies, which might be termed ‘health education’, usually involved a relatively short follow-up. The principle finding in meta-analysis was the effectiveness of fluoride to prevent caries (Kay and Locker 1997). A less rigorous approach adopted by Sprod et al. (1966) allowed exploration of other avenues of activity and research but still concluded that there was little evaluative literature in relation to the broader issues of health promotion.
One problem of broad strategies to promote health is that they do not lend themselves to current concepts of outcome evaluation (Sprod et al. 1996; Health Education Board for Scotland 1996; Stillman-Lowe 1998). The link between environment and oral health is indirect and is often mediated by individual behaviours. It is difficult to construct formal randomized controlled trials for this type of intervention and any health gain may take some time to become measurable. All the effectiveness reviews called for more careful evaluation and for the development of outcome measures more appropriate for oral health promotion. One core concern is the question: ‘What is oral health?’
Therefore oral health promotion finds itself at a cross-roads. Broad social and environmental approaches which act at the level of determinants of health and common risk factors for disease offer radical and exciting opportunities to promote health. However, in an increasingly restricted financial climate and with commensurate demands for evidence of effectiveness, proponents of health promotion must act to show how these broader approaches can deliver their promise.
The use of fluoride
The presence of fluoride at the interface between plaque and dental enamel inhibits the development of caries. To be most effective, fluoride should be present both before the teeth start to develop and then continuously throughout life. These findings suggest its effect is derived from a combination of modes of action. Three modes currently receive the most attention: the effect of fluoride on plaque metabolism, the effect of its incorporation during tooth development, and its effect on the dynamics of demineralization and remineralization in exposures which occur after tooth development.
Fluoride is present in dental plaque at concentrations 50 to 100 times higher than in saliva. At these concentrations it can affect the plaque metabolism to prevent the adhesion of plaque to the teeth. As the organisms produce acids, fluoride may be released from the plaque matrix. At these yet higher concentrations it may kill or inhibit acidogenic organisms and so negatively reinforce acid production. The presence of fluoride during dental enamel hydroxyapatite formation may allow its incorporation into the crystal lattice to produce the larger and more stable crystals of fluorapatite which are less soluble. A similar phenomenon occurs during exposure to fluoride after tooth development. The high concentrations of fluoride present in plaque at low pH increases the tendency for enamel to remineralize rather than demineralize. As the minerals precipitate back onto the enamel surface, the available fluoride is incorporated onto the remineralizing enamel as fluorapatite or calcium fluoride, both of which inhibit future demineralization.
The beneficial effect of fluoride on dental health was discovered as a consequence of investigations of endemic developmental defects of teeth in Colorado. McKay implicated the water supplies in the aetiology of the staining and pits and discovered that teeth with defects were less susceptible to dental caries than those without (McKay 1933). The staining was shown to be due to fluoride which existed in some of McKay’s samples at levels as high as 14 ppm.
Dean et al. (1941) went on to demonstrate the inverse relationship between dental caries and the fluoride concentration of drinking water (and the associated fluorosis) in two cross-sectional ecological studies (now called the ’21 Cities Studies’). The first intervention trial of fluoridation started in Grand Rapids in 1945 (Dean et al. 1950). Since then, similar studies have taken place in many countries including the United Kingdom, the Netherlands, and Australia (Murray et al. 1991).
By 1998, approximately 60 countries had reported projects to fluoridate public drinking water supplies. The entire populations of Hong Kong and Singapore receive fluoridated water, 67 per cent of those in Australia, 62 per cent of the United States, and approximately 10 per cent of the United Kingdom.
Where it is possible, fluoridation remains the most cost-effective method of reducing the experience and burden of dental caries. Indeed, it is possibly one of the most cost-effective public health and health promotion measures undertaken in industrialized countries in the last 50 years (Sprod et al. 1996). Many of the studies evaluating water fluoridation were conducted in the middle of the twentieth century and lack the scientific rigour of today’s standards. A recent systematic review found no randomized controlled trials of water fluoridation (McDonagh et al. 2000). Nonetheless, the conclusion was that fluoridation was effective, with a number needed to treat of 6. This figure is relatively high because the incidence of dental caries is relatively low even in the absence of water fluoridation. Fluoridation also prevents the impacts of oral disease by reducing the number of children with toothache and the number who require a general anaesthetic for dental extractions.
Sequential cross-sectional studies show that the maximum benefit occurs in children who have been exposed to fluoridated water since birth (Groeneveld et al. 1990). Since the permanent teeth do not begin to erupt until 6 years of age, these data demonstrate that fluoride is beneficial both before and after the teeth erupt. For maximum effect, exposure should be continuous throughout life (Attwood and Blinkhorn 1988). The benefits continue through adulthood (Murray 1971). Long-term exposure also protects against root caries of the teeth of older adults should they become exposed (Burt et al. 1986).
There is some evidence that water fluoridation also reduces socio-economic inequalities in caries experience (McDonagh et al. 2000). A series of studies conducted in northeast England show that fluoridation is effective across the spectrum of society but more teeth are saved in children from lower socio-economic status families (Carmichael et al. 1984, 1989). Several other groups have investigated the nature of this relationship between socio-economic status, fluoridation, and caries (Treasure and Dever 1994). Slade et al. (1996) used a range of measures of socio-economic status to show that the presence of fluoride in the drinking water had an additive interaction with socio-economic status in reducing caries experience in 6- and 12-year-olds. In deciduous teeth, fluoridation reduced the difference in caries between rich and poor by the equivalent of one affected tooth surface per child.
The optimal concentration of fluoride in drinking water depends on other exposures to fluoride and on the amount of water drunk. Natural sources of dietary fluoride include tea and the skin and bones of fish (Jenkins and Edgar 1973; Duckworth and Duckworth 1978). Fluoride is also present in foods and beverages processed in areas where the water is fluoridated and there is evidence that it exerts a ‘halo effect’ which protects people who only receive fluoridated water in this form (Newbrun 1989; Slade et al. 1996). However, in many developed countries the largest sources other than that added to the drinking water are from the fluoride added to toothpastes, mouth rinses, and gels.
The amount of fluid drunk is directly related to climactic temperature. Dean et al. (1941) originally suggested that the optimal concentration for water fluoridation was 1 ppm (1 mg/l). Since then there has been recognition that living in a warm climate might lead to a high daily dose of fluoride and an awareness that we are exposed to fluoride in other forms. Consequently, lower levels of fluoride are used in warmer climates (US Public Health Service 1962; WHO 1994). For example, the concentration in Hong Kong is 0.5 ppm In Australia, adjusted concentrations vary between 0.6 ppm in Darwin in the subtropical north to 1.1 ppm in Hobart in the more temperate south (Spencer et al. 1996).
In many situations fluoridation is the most cost-effective method of administering fluoride. A modest capital investment is required to install the machinery to administer and regulate the addition of fluoride to the drinking water. The whole population is affected and individuals need make no additional effort (such as visiting the dentist) to obtain the benefits. Fluoridation continues to be effective even at the low levels of caries incidence currently seen in the developed world, and the repeated low-dose application achieves the optimal pre- and posteruptive effects. However, fluoridation is less cost-effective in areas without reticulated water supplies serving large populations. In those areas where communities are served by a large number of smaller water supplies other methods of administering fluoride are required.
Toothpastes are mixtures of abrasive cleaning agents and refreshing flavourings. They present a good vehicle for the frequent low-dose application of fluoride to increase its availability in dental plaque. Proprietary preparations use a number of agents including sodium fluoride and sodium monofluorophosphate. Stannous fluoride has been used in the past but stained the teeth.
In children, fluoride toothpastes reduce the 2-year incidence of caries by up to 30 per cent (Murray and Naylor 1996) and there is a small additive effect when they are used in areas with water fluoridation (von der Fehr and Moller 1978). Sodium fluoride toothpastes are also effective in preventing caries of the roots of the teeth in older people (Jensen and Kohout 1988).
The effectiveness is primarily related to the concentration of fluoride in the paste up to levels of 2500 ppm (2.5 g of fluoride per kilogram), although most preparations for adults contain approximately 1000 ppm Between 1000 and 2500 ppm each additional 500 ppm provides an additional 6 per cent reduction in caries incidence (Stephen et al. 1988). The agent used is less important as long as it is compatible with the abrasive (Holloway and Worthington 1993; Johnson 1993; Stookey et al. 1993; Volpe et al. 1993). Early fluoride toothpastes used chalk as the abrasive, but this reacted with the fluoride and prevented its release.
In some countries there are special formulations of toothpaste available specifically for children. These toothpastes use lower fluoride concentrations to prevent ingestion of excess fluoride and reduce the risk of dental fluorosis. Again, the effectiveness is related to concentration but preparations containing 500 ppm appear to be similarly effective when compared with conventional preparations (Winter et al. 1989).
Therefore toothpastes offer a safe and effective vehicle for the administration of fluoride. The protective effects reported in trials are smaller than those in water fluoridation studies because fluoridation studies usually consider lifetime exposure to fluoride whereas toothpaste trials last for only 2 or 3 years. The addition of fluoride to toothpaste is also compatible with market interests as manufacturers compete to produce the most effective agent. However, the use of fluoride toothpaste has a distinct disadvantage as a broad preventive strategy—it relies on people brushing their teeth. In developed countries, poor oral hygiene and high caries incidence are associated (although not necessarily causally) and so the people who have most to benefit from the use of fluoride toothpastes are less likely to use them frequently. In developing countries, there may not be a tradition of tooth cleaning with toothpastes and Western proprietary brands are likely to be expensive.
Other vehicles for administering fluoride
Other vehicles for administering fluoride can be broadly categorized by whether or not they are taken systemically. Any fluoride taken systemically is liable to have a pre-eruptive effect if it is taken at the correct time. Since systemic fluorides are taken by mouth they are likely to have topical posteruptive effects also.
Fluoridized salt is used by 70 per cent of the population of Switzerland in areas where water fluoridation is not possible (Marthaler 1983). Observational studies of children in that country and in Hungary suggest that the use of salt containing 250 mg fluoride per kilogram has a caries-protective effect, although perhaps not of the same magnitude as that of fluoridated water (Toth 1976; de Crousaz 1985). A controlled study in Colombia demonstrated 48 and 50 per cent reductions in caries incidence (depending on the formulation used) compared with a 60 per cent reduction with water fluoridation (Mejia et al. 1976). Therefore fluoridized salt is protective but its use needs to be sustained (Stephen et al. 1999).
Fluoride may also be added to milk, school drinking water supplies, and fruit juices. Fluoride was added to the drinking water of schools in the United States for a number of years. Several accidents resulting in acute fluoride poisoning mean that this method is no longer recommended in that country. Early studies using fluoridized milk produced promising results but were flawed. A randomized double-blind trial showed a 43 to 48 per cent reduction in caries after 5 years (Stephen et al. 1984). Despite concerns that fluoride added to milk might bind with calcium or proteins to reduce its topical effect (Duff 1981), a number of schemes are being planned in northern England.
One study has tested the effect of fluoridized orange juice. A reduction in caries incidence was observed compared with a group not receiving a drink, but the incidence was also reduced in a group of children receiving a placebo juice without fluoride (Gedalia et al. 1981). The use of citrus drinks as a vehicle for fluoride may no longer be recommended because of concerns about the direct erosive effect of the drinks on the teeth.
Dietary fluoride supplements have been used in efforts to duplicate the fluoride intake of drinking water at 1 ppm They usually take the form of sodium fluoride tablets which are sucked or chewed and then swallowed. Early studies of their pre-eruptive effects were flawed by problems of self-selection, lack of controls, and non-blinded examiners, and so failed to distinguish between the effectiveness of the supplements and the confounding effects of patient compliance and other oral-health-related behaviours. Clinical trials of their use after the eruption of the teeth have been more robust and reveal significant preventive effects (DePaola and Lax 1968; Driscoll et al. 1978; Stephen and Campbell 1978).
One of the problems of fluoride supplementation is that programmes often rely on the compliance of individuals and their families with an additional health-directed behaviour. Many of the people most susceptible to caries find this new behaviour difficult to adopt. Even in the most compliant individuals, fluoride supplements do not perfectly mimic the effect of water fluoridation since the fluoride is taken as a daily bolus associated with dental fluorosis (Ismail and Bandekar 1999). As a public health measure for children dietary fluoride supplementation is appropriate only for individuals at high risk for dental caries. National bodies in the developed world recommend a number of broadly compatible dosing schedules determined by the age of the child and the fluoride concentration of the drinking water (Riordan 1999). Most schedules for children have been revised downwards in the last 10 years. Dietary fluoride supplements may have some benefit for older people who are more susceptible to root caries in whom there is no risk of fluorosis.
A number of methods of professional application of fluoride have been tried over the years. Gels containing relatively high concentrations of fluoride were applied to the teeth in trays and were effective but only whilst they were being used. Particular care was needed to minimize fluoride ingestion (LeCompte 1987). More cost-effective ways of administering fluoride are usually available.
Safety of fluoride used as a dental public health measure
Fluoride is freely available in the natural world. It is present naturally in almost all fresh groundwaters and is also consumed in some foodstuffs such as fish (especially the skin and bones) and tea. It is difficult to understand how any form of life has evolved and survived unless it was fully able to cope with continuous uptake of fluoride from its environment (Murray et al. 1991). Such is the case with humans who thrive in areas where the fluoride concentration of drinking water is several times higher than the therapeutic doses used to prevent dental caries.
In acute poisoning the certain lethal dose is 32 to 64 mg fluoride for each kilogram of body weight and the safely tolerated dose is 6 to 16 mg/kg body weight. In chronic exposures the safely tolerated dose is lower. Approximately 99 per cent of fluoride is stored in the hard tissues and it is there that the signs of chronic toxicity are evident. Skeletal fluorosis manifest as osteosclerosis, calcification of tendons, and exostoses occurs at water fluoride levels over 8 ppm (Srikantia and Siddiqui 1965). Industrial workers exposed to fluoride absorption of 14 to 68 mg/day for 20 years had skeletal fluorosis and gastric diseases. Radiographic changes are not apparent in areas where the water contains fluoride at up to 4 ppm (Morris 1965). If 1 to 2 litres of water are consumed daily, the exposure to fluoride at this concentration would be 8 to 16 mg/day. People in the United Kingdom who drink a lot of tea may take in 8 to 10 mg of fluoride per day (Jenkins and Edgar 1973; Walters et al. 1983).
Dental fluorosis is hypomaturation or hypomineralization of the teeth due to chronic ingestion of fluoride. It has a variety of presentations from small white flecks on the tooth to larger white opacities. In the most severe cases large areas of the enamel may be absent. The prevalence and severity of the disease are related to exposure to fluoride, particularly during the third year of life when the crowns of the upper central incisors are being developed. Exposure to fluoride in a number of forms, including drinking water and toothpaste, is associated with dental fluorosis (Hawley et al. 1996; Clark and Berkowitz 1997). The link between dietary fluoride supplements and dental fluorosis is particularly strong, and for this reason they are not advised as a public health measure for children in any but the most caries susceptible (Wang et al. 1997; Ismail and Bandekar 1999; Riordan 1999). Other strategies to avoid fluorosis involve brushing children’s teeth with only a small blob of low-fluoride toothpaste.
Whilst most studies conducted in areas of optimal or near-optimal water fluoridation show some fluorosis, it is infrequently severe (Clark and Berkowitz 1997; Rock and Sabieha 1997). Most cases of fluorosis cannot be noticed by lay people at conversational distance and many young people regard mild fluorosis as more attractive than unaffected teeth (Riordan 1993; Hawley et al. 1996).
Fluoride is frequently said to have a number of other adverse effects including cancers and diseases of most other body systems (Royal College of Physicians 1976). Perhaps the most famous claim is that water fluoridation was associated with crude cancer death rates in the 10 largest cities of the United States (Yiamouyannis and Burk 1977). This association was roundly criticized and found to be spurious in two independent analyses accounting for age, sex, and racial differences between the cities (Oldham and Newell 1977; Newbrun 1989).
The literature on the safety of the therapeutic use of fluorides, and in particular water fluoridation, is extensive and not always of the highest quality. However, a number of independent reviews have been and continue to be conducted including those by the Royal College of Physicians in London (1976), the British Department of Health and Social Security (Knox 1985), the Australian National Health and Medical Research Council (1991), WHO (1994), and McDonagh et al. (2000).. These reports consistently fail to find associations between water fluoridation and any adverse effects other than dental fluorosis.
There are active antifluoridation lobbies in most developed countries. Such groups tend to be small but very enthusiastic and vociferous with an impact which is often disproportionate to their size or the amount of support they garner. The general arguments given against water fluoridation fall into four main categories. Fluoridation is said to be unsafe, to be ineffective, to constitute mass medication, and to remove the freedom to drink pure water. This very brief review attempts to convey the overwhelming evidence for the effectiveness of water fluoridation in the prevention of caries. As mentioned already, the effectiveness and safety of water fluoridation have been reviewed at a national and international level by several independent bodies and all have supported its continued use. Water supplies are already treated with a number of chemicals to render them fit to drink and so there are precedents for mass medication if it is for the public good. The argument in favour of a ‘right’ to pure water is more fundamental and emotive. Advocates of fluoridation take a utilitarian view that the sacrifice of this right by the few supports the rights of many to have oral health.
The debate about fluoridation is an interesting one. Antifluoridationists tend to come from relatively healthy middle-class groups. Because children in these groups have the lowest caries experience, they have the least to benefit from the intervention. Unfortunately, the effect of the antifluoridationists is to maintain social inequalities in health. Antifluoridationist arguments are often alarmist and sometimes unorthodox from the viewpoint of scientists. Public debates between pro- and antifluoridationists often end in profluoridationists attempting to refute, in detailed scientific terms, an extensive list of claims. With the current mistrust of science, it can be difficult to make such a position attractive in the face of very emotional arguments. Some proponents of fluoridation avoid open debate with antifluoridationists for this reason.
Sugars are the major dietary determinant of dental caries experience and are a necessary cause of clinically significant decay. However, evidence that practical health promotion interventions can reduce their intake and so reduce the incidence of caries is lacking (Kay and Locker 1997). Many studies of health education interventions have used self-reported sugar consumption as the primary outcome with the obvious danger of ascertainment bias (Tan et al. 1981; Schou 1985). Studies which have measured clinical outcomes have combined health education approaches with the use of fluorides and thus the independent effect of the health education cannot be assessed.
Some of the data which implicate sugars in the aetiology of caries suggest that restriction of dietary sugar is preventive. For example, per capita sugar supplies and caries experience data correlate significantly in simple national ecological comparisons (Sreebny 1982). A children’s home in Australia had a dietary regimen with almost no sugar and the children had very low caries levels until they were allowed to make their own food choices at the age of 12 years. Likewise, caries levels fell in parallel with the availability of sugar during the Second World War (Toverud 1957).
Whether these findings can be translated into effective public health strategies remains uncertain. A health-directed food policy seems logical. A common risk factor approach might impact on dental diseases as well as on obesity, diabetes, and cardiovascular diseases. Possible strategies fall within the framework of education, substitution, regulation, pricing, or provision (Sanderson 1984). However, few countries have such policies in place and the resources of health advocates are very limited compared with those of the affluent and powerful lobby of the commercial food industry. Despite these difficulties, it is by operating at this level that public health might have its greatest impact.
As well as approaches aimed at individuals, education can take the form of authoritative dietary guidelines to inform national policies, community initiatives, and caterers. The Committee on Medical Aspects of Food Policy works within the United Kingdom Department of Health and advises the government on food policy relevant to health. Its 1989 the report Dietary Sugars and Human Disease focused on ‘non-milk extrinsic’ sugars by which it meant all sugars other than those taken in fresh fruit or milk (Committee on Medical Aspects of Food Policy 1989). It recommended that the consumption of non-milk extrinsic sugars should be reduced and replaced by fresh fruit, vegetables, and starchy foods. A subsequent report, Dietary Reference Values for Food Energy and Nutrients for the United Kingdom set a target for average non-milk extrinsic sugar consumption to constitute no more than 10 per cent of total dietary energy intake, which is approximately 60 g/person/day or 20 kg/year (Committee on Medical Aspects of Food Policy 1991). One important consequence of such an authoritative body making these recommendations has been that numerous other British organizations have followed suit with compatible guidelines.
Dietary sugars can be substituted with artificial sweeteners to reduce caries increments (Frostell et al. 1974; Scheinin and Makinen 1975). Sales of sugar-free carbonated drinks in Europe and North America demonstrate the compatibility of this tactic with commercial interests. However, substitution of dietary sugars has only limited potential in oral health promotion. The manufacture of many foodstuffs relies on the bulk and other specific properties of sugars. In addition, some sweeteners have side-effects, and resistance to the extended use of artificial sweeteners persists.
Regulation of advertising and labelling of foods in tandem with the effective use substitution is illustrated by a partnership between dentists and the confectionery industry in Switzerland. The Zahnfreundlich (tooth-friendly) logo is used to label non-acidogenic confectionery (Rugg-Gunn 1997). The label is well recognized by children, is commonly seen on confectionery, and is thought to have been effective in reducing levels of decay (Marthaler 1990b). Fiscal policies might be used to discourage the manufacture and sale of sugar-containing products. All of the above approaches and direct consumer pressure can be brought to bear on caterers and retail outlets to provide food in a way that makes the healthy choices the easier choices. There are numerous other examples of approaches which may reduce sugars consumption and an exhaustive list is presented by Sheiham (1995).
Since plaque is so strongly implicated as a necessary cause of periodontal diseases, it is logical that tooth cleaning should be the cornerstone of their management and prevention. Interventions aimed at improving oral hygiene can be successful and achieve a commensurate reduction in gingival inflammation (Kay and Locker 1997). Interestingly, interventions carried out in dental surgeries have been more effective than school-based interventions. However, most studies have had short follow-up periods and the effectiveness of even the best interventions diminishes with time. Therefore few data show that attempts to improve oral hygiene to prevent destructive disease are effective. Earlier research showing that frequent professional cleaning reduces periodontal destruction had design flaws (Axelsson and Lindhe 1978). Nonetheless, there remains a consensus that the best public health approach to improve periodontal health remains with improved oral hygiene.
The relationship between plaque removal and tooth decay is much more contentious. In Denmark, much preventive dentistry is based on the premise that cleaning the teeth prevents decay. Proponents of this policy cite an uncontrolled study involving both patient education and professional cleaning with a fluoride paste (Carvalho et al. 1992). In a carefully designed trial, a similar intervention did not demonstrate any additional preventive effect above a standard preventive programme of fissure sealants and locally applied topical fluoride received by the control groups (Arrow 1997). Sutcliffe’s (1996) traditional review considered the effect of research methodology on the observed relationship between oral cleaning and dental caries and concluded that there was ‘no unequivocal evidence that good oral cleanliness reduces caries experience’. This area of research is fraught with difficulty. As well as the difficulties of measuring dental disease, studies are susceptible to selection bias, leakage of intervention, and the probable confounding effects between self-reported behaviours, diet, and oral hygiene. Studies where professional cleaning has been effective have used pastes containing fluoride (Ripa 1985; Carvalho et al. 1992).
What is known is that brushing with a fluoride toothpaste is effective in preventing caries. Therefore brushing as it is currently practised in most developed countries combats both caries and periodontal diseases and is to be encouraged.
The systematic reviews cited above demonstrated that it is difficult to achieve sustainable changes in oral hygiene behaviour. A recent study of teenagers found good oral hygiene to be associated with not smoking, exercise, healthy eating, managing in school, and having confidence in one’s family (Schou 1998). These types of findings invite the common risk factor approach in which oral cleanliness is promoted as both a health-related and health-directed behaviour where cleaning ones teeth makes one feel and look nice and is part of a positive and healthy lifestyle. Toothbrushing is a habit learnt as a young child and therefore is difficult to change later in life (Blinkhorn 1978). This behaviour is often an established routine before the child has seen a dentist, and interventions via health-care workers and social agencies working with young children and their mothers may be useful.
The role of smoking in the aetiology of oral cancers and periodontal diseases has already been discussed. Johnson (1997) has listed at 20 oral conditions either directly or indirectly associated with tobacco smoking. In addition to the well-known benefits to cardiovascular and respiratory health, cessation of smoking almost eliminates the increased risk of oral cancer within 5 to 10 years.
Many of the oral conditions, such as stained teeth, receding gums, and altered taste, are readily perceptible to the individual and may encourage or reinforce the desire to stop smoking. The dental team are also often aware of the personal and social circumstances (for example, pregnancy or a new job) that prompt people to give up. Therefore smoking cessation is another area where it is particularly appropriate for dentistry to become integrated into a common risk factor approach (Grabauskas 1987). As clinicians the dental team can be effective in supporting smoking cessation by providing advice (Warnakulasuriya 1984; Raw et al. 1998). Indeed, a group of dental practitioners achieved 11 per cent smoking cessation among their patients at 9-month follow-up in dental practices in the United Kingdom (Smith et al. 1998).
Prevention of accidents
Several strategies can be used to reduce trauma to teeth. Playground surfaces can be made of impact-absorbing materials which cushion against trauma. Unfortunately, orthodontic treatment of large overjets is complex and prolonged, but can be justified in children of 8 or 9 years to reduce the risk of trauma (Welbury 1996).
The use of mouthguards is compulsory for some sports in some countries. Mouthguards not only prevent dental injuries in sport but also prevent laceration of the facial soft tissues against the teeth (Garon et al. 1986; McNutt et al. 1989). By absorbing the force of anterior blows they reduce posterior and superior displacement of the mandible. In so doing they reduce the risk of mandibular fracture and may protect the cranial cavity. Mouthguards are usually made of a copolymer of polyvinyl acetate and polyethylene. The most basic type may be obtained prefabricated in a range of sizes. A more sophisticated type may be adapted to fit the mouth, typically by softening it in hot water first. Custom-made devices constructed on models made from impressions of the teeth are the most comfortable and can be made to support the lower teeth and mandible during trauma (Chapman 1985; Stokes et al. 1987).
Ensuring access to appropriate preventive care
There has been disillusionment with the prevailing biomedical model of health care. By focusing on the diseases of individuals, it emphasizes the hierarchy of professionals over lay people and treatments rather than prevention. All of these things have taken place with substantial economic and social costs and yet medical care has made a relatively small contribution to health (Illich 1976; McKeown 1976). The biomedical approach distracts attention from the wider social, political, and economic determinants of health. The primary health care approach is a philosophy which recognizes that these determinants are more important than medical interventions (WHO–UNICEF 1978).
Dental services are just as susceptible to the criticisms of the medical model of health care. Just as we know that medical services have limited effect on health, so we are aware that dental treatment has made a relatively small contribution to oral health (Nadanovsky and Sheiham 1994, 1995). Dental services sometimes have the appearance of aiming to provide dental treatment rather than aiming to achieve oral health. Data from the 1970s show that dental services explain 3 per cent of the variation in oral health of 12-year-olds in developed countries compared with the 65 per cent contribution made by broader socio-economic factors. Furthermore, the interventions used in dentistry may also be clinically inappropriate. Dentistry has adopted a surgical approach to treatment with a cycle of placing and replacing fillings. It has long been recognized that the quality of many fillings is not high and that even the decisions to place fillings are idiosyncratic (Elderton 1976; Elderton and Nuttall 1983). Since fillings are often replaced many times over a lifetime, the remaining tooth is increasingly damaged with each new filling.
As well as having little positive impact on oral health, clinical dental services ignore the determinants of disease. With its emphasis on personal behaviour and even with the search for specific periodontal pathogens, clinical dentistry and much dental research actually divert attention from the factors which determine oral health and disease.
Dental services are also costly. National Health Service dentistry costs £1.4 billion per year in England and Wales. Compared with the potential costs of treatment, the resources available are few and are likely to reduce in future. Curative services serve those who can afford them. As well as creating dependence on professionals, the services become focused on those with least health problems.
Since these problems of medical and dental care exist in parallel the same kinds of changes are applicable to both. Twenty years after the introduction of Health for All there are still too few resources, the resources which are available are still poorly allocated, medical staff still congregate around the wealthy people, ordinary people have little control over their own health, and health professionals still do not trust people to make good decisions about their health (Mahler 1981). All of these points apply to dentistry. Worldwide there are people who cannot attend and/or cannot afford dental treatment in its current guise. Even in countries with well-developed socialized systems of dental care, there are major inequalities in oral health (Watt and Sheiham 1999). Dental services are overdue for an evaluation and reorientation. A more holistic practice of dentistry in line with the primary health care approach will also ensure that services are more equitable and appropriate. Such a move will require a challenge to the professional status quo (Dickson 1993).
Whilst realizing the limitations of clinical dentistry, it is important to recognize that it may have a role (as yet undemonstrated in clinical trials) in reducing the psychosocial impacts of oral disease. For this reason it is essential that we generate a greater understanding within dentistry of the nature of oral health. The movement to identify more relevant measures of oral health to assess treatment need and the outcomes of care should be encouraged (Slade 1997). The evidence-based approach, the use of clinical governance, and managed care should provide both the impetus and the means to ensure that only effective and efficient interventions are used.
Dental surgeries are a natural health-related setting for health promotion. Practice-based oral health promotion activities provide an opportunity to increase knowledge and promote self-esteem and empowerment. Their role could be expanded by adopting a common risk factor approach (Croucher 1993). However, practice-based health promotion is only useful for those who attend the services and may exclude those people with the greatest need who do not. In addition, there needs to be a change in emphasis in health education from the elitist prescriptive medical model which ignores the needs of people it serves and so blames ‘victims’. Patients should not feel they are being chastised or told to do things. A more effective approach would be a patient-centred model which respects patient autonomy and seeks their active participation in defining their needs (Croucher 1989).
One particular aspect of dentistry in many countries that may need to be revised is the system of payment of fees to dentists for each item of service provided. Fee-per-item service payments encourage dentists to work quickly and have been associated (in the past at least) with overtreatment. This system of payment tends to encourage the curative technical approach to treatment, unless there is a specific fee for prevention. Conversely, whereas salaried dentists have both more time and incentives to emphasize health promotion their productivity is lower (Schou 1993). The potential disadvantages of capitation systems are that they may lead to undertreatment of existing patients and may encourage dentists not to accept patients with high treatment needs (Schoen 1991). Interestingly, there has not been evidence of widespread neglect since the introduction of capitation payments, as long as there is an additional fee for treatments provided (Daley et al. 1994).
Other specific changes which could be made to ensure access to dental services can be categorized in the framework used by Penchansky and Thomas (1981). Dental services must be available, accessible, affordable, acceptable, and accommodating.
Clearly people cannot use services that do not exist, and so increasing their availability has a direct effect on service use (O’Mullane and Robinson 1977; Brennan et al. 1997). One way of making dental services more available at limited cost is to delegate care to auxiliary staff. With the decreased incidence of dental caries in developed countries, the vast majority of new cavities in children are small and relatively simple to treat. It is therefore not cost-effective to employ highly trained and highly paid dentists to undertake this less demanding and repetitive work. A number of countries including Australia, New Zealand, Canada, and the United Kingdom employ staff with a limited repertoire of treatment options (variously called school dental nurses, dental auxiliaries, and dental therapists) who provide high-quality care at lower cost (Office of the Auditor General Western Australia 1995). Similar data exist for dental hygienists. Dental auxiliary staff work under the supervision of a dentist. By reducing the level of supervision required and expanding the role of ancillary staff the availability of care can be increased whilst limiting costs. Dental hygienists can work independently without reducing either the quality of treatment or patients’ satisfaction with it (Perry et al. 1997; Freed et al. 1997). Likewise, hygienists can be trained to conduct clinical examinations in dental surveys with no compromise to the quality of the data (Kwan et al. 1996).
Clearly the expanded use of dental auxiliaries threatens the monopoly on the provision of dental treatment held by dentists. The dental profession is the most constant barrier to the wider use of dental auxiliaries (Riordan 1997). The American Dental Association, for example, has consistently opposed their use since 1975 (Burt and Eklund 1999).
Other characteristics of dental services which limit access were explored in a qualitative investigation of people who did not go to the dentist (Finch et al. 1988). The costs of treatment, the need to make an appointment, and the opening hours of dentists all deterred attendance. These obstacles can be reduced by providing subsidized care, arranging services where no appointment is necessary, and where treatment can be provided outside office hours.
Whilst the prevalence of dental caries in many developing countries is still low, other diseases such as oral cancer and dental fluorosis are more common than in most developed countries. Non-industrialized countries also suffer from a shortage of resources including human resources, appropriate technology, and universally available power supplies. Over the last two decades, the additional burden of meeting the costs of the infection control implications of the HIV epidemic have exacerbated any deficiencies in resources (Akpabio 1993).
The traditional curative approach to dental health is limited in any setting but these limitations are more extreme when they are exported to the developing world. The surgical approach to dentistry used in industrialized countries is technology intensive and requires an infrastructure of continuous power and water supply. It involves expensive equipment which is difficult to use and maintain. Dentists, therefore, need to treat patients who can help them recoup their costs. These pressures limit the availability of services and contribute to the inequalities in their provision. Hobdell (1993) has described this situation as ‘trying to implement a type of oral health care developed mainly in the last century in another part of the world using equipment and materials developed for use in an entirely different socio-economic and political setting’. Indeed, large parts of the Western model of dental care may be inappropriate in developing countries, including an overemphasis of clinical surveys in health-care planning. Services based on normative assessment limit community participation in health care and ignore the sociodental implications of oral disease. They may also overcomplicate health care. In one notorious example, survey data were used to calculate the periodontal treatment needs of children in Kenya (Manji and Sheiham 1986). Using the WHO model, the treatment proposed would have used the entire dental human resources of Kenya for up to 21 years, allowing for no other care. Services could concentrate on the relatively few conditions which comprise the bulk of oral health problems: toothache (not tooth decay), trauma, oral infections, and neoplasms (Hobdell 1993).
The primary health care approach is still relevant to the provision of dental services in all countries but it is particularly applicable to the developing world. It has five principles: an equitable distribution of services, community involvement in health, a focus on prevention, the use of appropriate technology, and a multisectoral approach. The Berlin Declaration on Oral Health and Oral Health Services in Deprived Communities provides comprehensive guidelines for planning, implementing, and evaluating oral health projects within this framework (Mautsch and Sheiham 1995). It was conceived by the Oral Health Alliance, an international network which provides support and information to colleagues working in this field (e-mail: firstname.lastname@example.org). Specific examples of activities within this framework are presented below.
Tudor Hart’s (1971) ‘inverse care law’ between the availability of services and the need for them also occurs in dentistry. It is particularly extreme in countries where there are wide disparities between rich and poor. In Africa, 80 per cent of the trained professional personnel live and work in affluent neighbourhoods in cities, although the same proportion of the indigenous population live in rural areas (Thorpe 1993). The scope for dental auxiliaries in developing countries may be greater since advocates of their use may not have to compete with the well-established political lobbies of dentists which exist in industrialized nations. Auxiliaries can be used to provide simple but essential treatments to extend the availability of services and reduce inequalities in access (Anumanrajadhon et al. 1996).
Models exist for identifying the types of personnel needed for oral health care in deprived communities along with training and evaluation methods (Samarawikrama 1995). Such models consider the frequency of problems, the difficulties encountered in undertaking the different roles, and the identification of the difficulties themselves.
Community involvement means that people are allowed to take control of their own health, and it is necessary if programmes are to thrive. It is perhaps the most difficult aspect of the primary health care approach since it requires that health professionals must relinquish their traditional hierarchical role. In addition, individuals and communities often regard health as beyond their control and may not regard oral health as a priority. There are isolated examples of wide involvement in oral health. In Brazil, health councils comprised of community representatives, health workers, and civil servants operate at the national, state, and municipal levels. Only in areas where there is a well-organized community have the local health councils been able to implement policy. One council in Porto Alegre identified oral health as a priority. Despite considerable opposition from local dentists and a scarcity of resources, it was able to create an emergency dental service and initiate preventive programmes in schools and health centres (Baldisserrotto 1995).
Focus on prevention
Prevention is universally accepted as an essential component of health care. However, if prevention is to avoid the existing system in which people are passive recipients of information and preventive therapies, it must adopt the principles of health promotion. Examples of a more participative role include the community involvement described in Porto Alegre and the use of individuals from local communities including children in preventive activities.
‘Appropriate technology’ is sometimes taken to mean ‘cheap’ and ‘second rate’. It is neither of these things, but is an approach which recognizes the needs and resources of the local community. The atraumatic restorative technique is a recent development which combines these requirements with new knowledge of the process of dental caries and developments in dental materials science (Frencken et al. 1996). It involves removal of decay with hand instruments and filling the cavities with glass ionomer cements. These cements are hand mixed with water on a small pad or slab. Upon insertion, the filling gradually leaks fluoride to prevent secondary disease around the cavity. All the instruments can be carried in a small case and treatment can be provided painlessly without local anaesthesia, at low cost, and without either electricity or expensive dental equipment. Non-dentists can be trained in the technique in a matter of weeks and manuals are available from the World Health Organization (WHO). The technique is most suitable for exactly the types of cavities which are found in many developing countries which do not have excessively high caries levels.
We have seen how an effective health strategy might involve a number of departments of both national and local governments, water providers, the educational system, community members, and health-care workers. All of the approaches to health promotion outlined in the second part of this chapter must be integrated. However, integration should mean more than using the resources of other sectors to promote oral health. Such an approach often means that dentists simply get teachers to provide dental health education which carries the risk of not truly involving the other sectors (Mautsch and Sheiham 1995).
Conclusions and future developments in dental public health
The last few years have seen remarkable developments in our understanding of the importance of oral health and its significance as a public health concern. There is a greater knowledge than ever before of the nature of the oral diseases which threaten health (dental caries, periodontal diseases, oral cancer, and dentofacial trauma), the epidemiology of those diseases, and the factors which determine them. Moreover, we are starting to accumulate a body of evidence on the effectiveness of health promotion and treatment strategies. Those strategies include the use of fluoride, food, and health policies to reduce sugars consumption, community approaches to improve body hygiene including oral cleaning, smoking cessation, policies on reducing accidents, and ensuring access to appropriate preventive care. Many of these strategies could work in common with approaches to the promotion of general health.
In keeping with the recognition that clinical services are a minor determinant of health, most of the oral health strategies discussed in this chapter do not involve clinical dental services. There is a developing knowledge of the relative impotence of clinical dentistry to bring about oral health and a greater awareness of its potential harm. The evidence of effectiveness should be used to identify beneficial interventions and should help reorientate dentistry from its traditional curative approach which focuses on the responsibility of clinicians and their individual patients. In so doing we may be able to move toward a more shared responsibility in which all participate.
It is important that all these strands of information are combined. Perhaps most important of all, we need a more universal understanding of what is meant by ‘oral health’ and its relationship with oral disease. The ways we measure health and the outcomes of interventions will determine not only which interventions we choose but whether we choose to intervene at all.
Future developments in dental public health can be considered in four areas: trends in oral health, the deprofessionalization of dentistry, technological developments, and relationships between oral and general health-care delivery.
Two trends in oral health have been observed. Some countries, particularly developing countries, are experiencing increases in dental caries. The increases are related to the adoption of Western dietary patterns high in sugars. Even if these trends are currently limited to more affluent city dwellers they represent worrying concerns for the future. The increase in treatment needs created by these trends is likely to place an unaffordably high burden on developing economies. To some extent this burden will be moderated by the low levels of perceived need in communities unused to receiving dental treatment. However, if the disability and handicap brought about by oral disease are to be minimized, then appropriate methods of treatment will be required. Numerous examples now exist of dental auxiliaries being used to provide a limited range of treatments in both the developed and developing world. Auxiliaries can be trained quicker to provide care to similar standards to dentists, but at greatly reduced costs. Food and health policies could also be used in countries with rising caries levels to control imports, the production and sale of cariogenic foods and drinks, while encouraging the use of traditional foods.
In many developed countries, the decreased caries incidence witnessed over the last two decades appears to have stabilized in young children. The trend may have stabilized but its effects will continue to change dentistry for decades to come. When coupled with demographic changes, changed attitudes towards oral health and the preservation of teeth seen in developing countries over the last 50 years, this trend produces an interesting pattern. On the one hand there is a growing and ageing group of younger people whose treatment needs will remain lower in terms of volume and complexity than preceding generations. On the other hand, there is a large group of older people who will live for longer and retain many heavily restored teeth for longer. These people will require more care, some of it more complex, than the generations that preceded them. It is difficult to predict whether there will be a net change in the need for dental care or in which direction such a change would be. One likely change will be a greater emphasis on specialization within dentistry. The majority of the young people’s needs will comprise simple one surface fillings which could be placed by auxiliaries. However, this change could be offset by the more complex demands of older people seeking dental implants and treatment for root caries and tooth wear which may remain in the domain of specialists.
A dominant political direction over recent years has been the deprofessionalization of dentistry. This trend is manifest in several different forms. In many developed countries, patients are demanding ‘rights’ as consumers of care. These demands are complemented by the application of marketing theory to dentistry, which places consumer satisfaction as an essential criterion in business success. Thus, patients have been directly and indirectly implicated in moves to regulate the way in which dentists market themselves and have ensured that patient satisfaction is an active concern of dentists. Similar principles are cornerstones of the primary health care approach and the Ottawa Charter for Health Promotion (named community participation and community action, respectively) (WHO–UNICEF 1978; WHO 1986). These activities take public involvement in oral health well beyond clinical dentistry. Even within clinical care, satisfaction is associated with patient compliance and is therefore regarded as an integral part of the process of care rather than just an outcome. Other agencies, such as governments and insurance companies, are increasingly involved in health care. Externally applied measures to minimize the costs of care and increase the accountability of health-care organizations whilst assuring the quality of care all serve to reduce professional power within dentistry.
This trend of deprofessionalization is likely to continue and may help to make oral care more relevant to the needs of the people it serves. Professions resist any tendency to undermine their power. This reaction could present an opportunity for dental public health to facilitate and manage the deprofessionalization of dentistry.
A number of technological developments may also influence oral health and care. The atraumatic restorative technique shows considerable potential for providing simple, inexpensive, and effective treatment for the type of minimal caries seen in developing countries. Because the technique requires minimal training and equipment it will allow services to be provided in relatively small and isolated communities. If the technique is used by partially skilled staff it may also contribute to the deprofessionalization of dentistry in these countries; it will certainly reduce the cost.
In developed countries osseo-integrated implants are increasingly used to support dental prostheses. By providing a stable and retentive base for both single and multiple tooth prostheses, implants show great potential for reducing the handicap brought about by oral disease. One disadvantage is that, for the time being at least, implant treatment demands considerable specialist expertise and is costly. Implants may therefore become a treatment limited to those who can afford them and thus contribute to inequalities in oral health.
Oral health care is becoming increasingly integrated with the delivery of other services. In policy terms greater integration can be seen as part of the multidisciplinary approach enshrined in the Alma-Ata declaration (WHO–UNICEF 1978). There are many examples of integration at the level of clinical service provision. Dental surgeries may be linked with other clinical services in health centres. In some cases dentists invite other types of health-care worker into their practices to provide services. At a broader level of health promotion, integration is particularly compatible with a common risk factor approach to disease. Health educators and health promotors recognize the value of involving other health-care workers, teachers, and other community workers, either as original deliverers or reinforcers of their messages. Oral health also becomes a consideration of local and national governments with debates about fluoridation of water supplies and whether agricultural and fiscal policy are used to promote oral health. It is the role of specialists in dental public health to act as advocates at all these levels.
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