Beltrán-Aquilar ED, Estupinan-Day S, Báez R. Analysis of prevalence and trends of dental caries in the Americans between 1970 and 1990s. Int Dent J. 1999; 49:322-329
Downer MC, Drugan CS, Blinkhorn AS. Dental caries experience of British children in an international context. Community Dent Hlth. 2005; 22:86-93
Marthaler TM, O'Mullan DM, Vrbic V. The prevalence of dental caries in Europe 1990–1995. Caries Res. 1996; 30:237-255
Whelton H. Overview of the impact of changing global patterns of dental caries experience on caries clinical trials. J Dent Res. 2004; 83:(Spec No C)C29-34
Petersen PE, Bourgeois D, Ogawa H, Estupinan-Day S, Ndiaye C. The global burden of oral diseases and risks to oral health. Bull World Health Organ. 2005; 83:661-669
Milsom KM, Blinkhorn AS, Tickle M. The incidence of dental caries in the primary molar teeth of young children receiving National Health Service funded dental care in practices in the North West of England. Br Dent J. 2008; 205
Kidd EA, Fejerskov O. What constitutes dental caries? Histopathology carious enamel and dentin related to the action of cariogenic biofilms. J Dent Res. 2004; 83:35-38
Featherstone JD. The continuum of dental caries – evidence for a dynamic disease process. J Dent Res. 2004; 83:39-42
McIntyre J. The nature and progression of dental caries. In: Mount GHW (ed). Barcelona: Mosby; 1998
Bjorndal L, Larsent T A clinical and microbiological study of deep carious lesions, during stepwise excavation using long time intervals. Caries Res. 1997; 31:411-417
Bader J, Shugans D Systematic reviews of selected dental caries and management methods. J Dent Educ. 2001; 65:960-981
Black GV.Chicago: Medicolegal Publishing; 1908
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Ricketts D, Kidd E, Innes NPT, Clarkson JE. Complete or ultraconservative removal of decayed tissue in unfilled teeth. Cochrane Database Syst Rev. 2006; 3
Dawson AS. Dental treatment and dental health. Part 1: a review of studies in support of the philosophy of Minimal Intervention Dentistry. Aust Dent J. 1992; 37:125-132
Evans RW, Pakdaman A, Dennison PJM, Howe ELC. The caries management system: an evidence based preventive strategy for dental practitioners. Application for adults. Aust Dent J. 2008; 53:83-92
Fejerskov O. Changing paradigms in concepts on dental caries: consequences for oral health care. Caries Res. 2004; 38:182-191
Burt BA, Pai S. Sugar consumption and caries risk: a systematic review. J Dent Educ. 2001; 65:1017-1023
Treasure ET, Dever SG. The prevalence of caries in 5 year old children living in fluoridated and non fluoridated communities in New Zealand. N Z Dent J. 1994; 88:9-13
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Moynihan PJ. Dietary advice in dental practice. Br Dent J. 2002; 193:563-568
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Davies RM, Davies GM. High fluoride toothpastes: their potential role in a caries prevention programme. Dent Update. 2008; 35:320-323
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Marinho VC, Higgins JP, Logan S, Sheiham A. Fluoride varnishes for preventing dental caries in children and adolescents. Cochrane Database Syst Rev. 2002; 3
Marinho VC, Higgins JP, Sheiham A, Logan S. Combinations of topical fluoride (toothpastes, mouthrinses, gels, varnishes) versus single topical fluoride for preventing dental caries in children and adolescents. Cochrane Database Syst Rev. 2004; 1
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This article highlights the fundamental issues which the primary care team should consider when developing preventive dental advice for their patients. Although it is important to have a clear understanding of the carious process, this knowledge must take account of social influences on health when assessing the preventive strategy for individuals. A key factor is that caries is a lifelong process involving fluctuations in demineralization and remineralization. The dental team should ensure that the oral environment favours remineralization and avoids irreversible loss of enamel and dentine. An understanding of this ‘see-saw’ process will influence not only our preventive philosophy but how we, as health professionals, diagnose and treat dental caries.
Clinical Relevance: Preventing dental caries is an essential skill for all dental professionals. This article brings together the scientific basis of the appropriate advice.
Article
Fifty years ago dental caries was prevalent in all developed countries and the dental profession was overwhelmed by the need and demand to treat the disease and its sequelae. Since then the prevalence and severity of dental caries has declined in all age groups. For example, in the United Kingdom the mean DMFT in 12-year-olds declined from 3.1 (1973) to 0.8 (2003)1 and in Australia from 4.8 (1977) to 1.1 (1993).2 An increasing proportion of adults are retaining more of their teeth into later life. In the United Kingdom, the percentage of edentate adults has declined from 37% in 1968 to 13% in 1998.3 The decline in caries levels has been accompanied by a change in the distribution of lesions; the relative contribution of pit and fissure caries to overall caries levels has increased.4
Despite these general improvements, caries continues to be a public health challenge, particularly in lower income and socially disadvantaged groups who experience disproportionately high levels of disease. In addition, the incidence of new carious lesions in adults is as high as that in children,5 with root caries affecting 29% of those aged 65 and over.3 Overall, caries has changed from a rapidly developing disease of childhood to a slowly progressing disease in adulthood.
These changes in the prevalence, pattern and severity of caries, plus the weight of evidence from systematic reviews that various topical fluorides6 are effective in preventing and controlling caries, provide an opportunity for dental professionals to deliver an effective level of prevention of caries for their patients.7-11 Indeed, the dental team should ensure that prevention of dental caries remains a priority for all patients, especially as a recent study reported that 25% of children, initially caries free, developed caries over the following three years.12 If dental professionals only provide prevention for those who present with caries, they will be doing a disservice to many patients.
The primary care dental team should consider three fundamental issues:
Patients who are already caries active should receive appropriate advice and care;
Patients who are free of caries require information and advice to maintain their oral health;
Consider the effectiveness of preventive strategies before embarking on operative procedures.
These points emphasize the need for a new approach to the delivery of care with greater emphasis on maintaining good oral health and reducing caries risk.
In order to develop strategies aimed at maintaining health or reducing risk for individuals, it is important to have a clear understanding of the carious process. Dental caries is not just holes in teeth, it is the endpoint of a complex series of reactions, both biological and social.
‘a dynamic, lifelong, complex molecular process active at the interface of susceptible tooth surfaces and the microbial biofilm that covers them’.
Micro-ecosystems exist at a number of sites on each tooth and there is a constant fluctuation between demineralization and remineralization. It is the bacterial activity within the biofilm which causes the pH fluctuations which lead to the cycle of demineralization/remineralization. The process has been likened to a see-saw;14 if the pH falls below a critical threshold then demineralization occurs and, if sustained, will eventually result in cavitation of the tooth surface.
Although these biochemical-bacterial models are important, it is essential to remember that caries has a multifactorial aetiology. There is a close interaction between destabilizing factors such as:
Frequent intake of sugary foods and drinks;
Presence of a plaque biofilm as a result of inadequate oral hygiene;
Acid production in the plaque;
Impaired salivary flow.
and protective factors such as:
Fluoride;
Normal salivary flow;
Infrequent intake of sugary foods and drinks;
Good oral hygiene.
In order to clarify and explain the concepts put forward in this paper, the sequence of events15 in the carious process can be summarized as follows:
Formation of a bacterial biofilm on the tooth surface;
Acidogenic plaque bacteria ferment refined dietary carbohydrates producing acids which can, once the pH falls below a critical threshold (pH 5.5 enamel; pH 5.9 dentine), dissolve the calcium phosphate mineral of the tooth enamel and/or dentine (demineralization).
If the pH subsequently rises above the critical threshold as a consequence of the neutralizing and dilution effect of saliva, there is sufficient Ca2+ and PO43- in the saliva to reverse the loss of mineral (remineralization).
The caries sequence can be altered by a daily oral hygiene routine that involves the use of fluoride. Fluoride has two principle mechanisms of action that can protect the dental enamel, namely by:
Inhibition of demineralization during an acid attack; and
Enhancement of remineralization.
Influence of restorative decisions and diagnostic threshold on prevention
Before discussing preventive strategies, it is essential to ensure that the restorative philosophy adopted by the dental team reflects knowledge of both caries and the properties of currently available restorative materials.
Dental health professionals should accept, in principle, that early carious lesions can be arrested if the cariogenic challenge is eliminated, or at least greatly reduced.16 Clinicians need to harness the full potential of preventive strategies and give them the opportunity to work.17 However, realistically there will often be a need to restore an individual tooth to full function.
It is surprising that the principles of cavity preparation espoused by GV Black18 in the early part of the 20th century should have persisted for so long. Black's cavity preparations adopted a mechanistic approach without recognizing the caries process as one of a balance between demineralization and remineralization. The removal of sound enamel and dentine to facilitate the retention of restorations and ‘extension for prevention’ are outdated modalities.
The rationale behind modern cavity design is as follows:19
Until recently, carious and softened dentine was removed down to a hard surface but the need to do so has recently been questioned. A Cochrane Systematic Review20 concluded that there was no difference in the incidence of damage or disease of the nerve of the tooth, irrespective of whether the removal of decay had been minimal or complete;
Extend the cavity according to the requirements of the restorative material used, rather than follow a preconceived plan.
Every effort should be made to protect the pulpal-dentinal complex from:
Toxic effect of restorative materials;
Bacteria (there should be no leakage at the restoration/cavity margin);
Thermal fluctuations.
How do dental professionals determine whether or not a lesion should be restored – what is the diagnostic threshold?
This threshold has changed over the years since it is now evident that enamel and dentine can be repaired by the judicious use of fluoride, good oral hygiene and dietary control. So, the motto, ‘if in doubt fill’ has been replaced with ‘if in doubt prevent’.21
The clinical diagnosis of caries has relied, for the most part, on the macroscopic appearance of a lesion; the key aspects at visual examination are:
Lesion size;
Depth;
Colour; and
Translucency.
The common aids to assist with diagnosis and assessment are:
Patients' reported symptoms;
Radiographs;
Pulp sensitivity testing.
A sharp probe may be used but minimal pressure should be applied to minimize potential damage to the tooth surface.22
Different diagnostic systems have been researched with varying degrees of success,23 some of the more common are fibre optic transillumination (FOTI), electric caries monitor (ECM), subtraction radiography, fluorescent techniques, visible light fluorescence (QLF), laser fluorescence (DIAGNODent) and enhanced visual techniques. All these systems rely on measuring changes in a specific physical signal rather than measuring the caries process itself.
Bader et al17 reviewed a number of caries clinical assessment techniques and found that traditional caries detection, utilizing visual and tactile examination, is a reasonable way to diagnose larger lesions but results in many early lesions being left undetected. One might ask if this is a problem if a preventive philosophy is adopted. All patients, whatever their caries status, should receive appropriate preventive advice and care and early lesions should be monitored to determine whether they have arrested or progressed. It is, therefore, important to use the best diagnostic methods to establish a true picture of the caries experience of each patient. However, use this information to plan preventive advice before removing and replacing tooth tissue.
Potential preventive strategies
The science behind caries reveals three central strategies which should be utilized by the dental team to prevent or control caries. These are:
Strategy 1
Regular disturbance of the plaque biofilm with a fluoride toothpaste. Reduce the frequency of consumption of refined carbohydrate24 and consequently the frequency and duration with which the pH falls below the critical threshold.
Strategy 2
Ensure an effective level of oral hygiene is maintained and that fluoride is readily available to inhibit demineralization and enhance remineralization of enamel and/or dentine. From a public health perspective, the most effective source of fluoride is found in natural and artificially fluoridated water supplies.25 However, sources of fluoride that the dental team can offer to individuals are toothpaste, mouthrinses, varnish, gels and supplements.
Strategy 3
Fissure sealants should also be included in the preventive armamentarium.
Preventive strategies
The decision to re-orientate one's dental practice to prevention rather than restoration requires a new focus.
Evans et al22 gave advice to the dental team on the essential information that a preventive practice should collect and this is outlined below with some slight modifications.
Summary of the caries management and data collection system
Visual examination;
Bitewing radiographic assessment;
Diagnosis and caries risk assessment;
Diet assessment;
Plaque quantity;
Develop a personalized preventive programme;
Monitor outcome;
Recall intervals tailored to caries risk status.
Visual examination
The teeth should be cleaned, dried and examined using good illumination. Lesions should be categorized as cavitated with dentine involvement or enamel only. Visual examination informs the need for a radiographic examination.
Radiographic assessment
Radiographs are frequently used in general dental practice and should be carefully assessed. The presence of early lesions on radiographs must be carefully recorded and monitored for any progression.
Assessment of caries risk
The data obtained from past and current caries experience should be reviewed and the potential for further caries assessed. It is then possible to plan an appropriate preventive strategy.
Diet assessment
The intake of sugary snacks and drinks can be recorded utilizing a 24-hour diet diary. Such an exercise is simple and will give an overall picture of the sugar challenge to the teeth. It has been suggested that a 3-day diet diary, which includes a weekend and week day, is a more useful educative tool, especially for parents trying to change a child's diet.26 There is no scientific evidence as to whether a 1- or 3-day diet record is better. However, some form of dietary analysis is essential to help individual patients reduce the frequency of consumption of sugar foods.27
The use of sucrose substitutes in snack foods and sweets is a practical way of reducing the cariogenic challenge and does not require any changes to an individual's eating pattern.28 In a dental context, xylitol has been the most widely tested of the sucrose substitutes. It is certainly safe for teeth and has been shown to be an effective tool for reducing dental caries. However, it is expensive and its widespread use in snack foods has not occurred. Currently, sugar substitution is not in general use and dental professionals need to continue with dietary advice to reduce the frequency of sugary snacks.27
Diet advice must also be tempered by the fact that confectionery companies spend large sums of money advertising the pleasures of sugary snacks and drinks. In order to have a realistic chance of success, our dietary education policy should look to modify the diet rather than suggest a complete change of dietary habits. A change in frequency of consumption of ‘between meal’ snacks is an achievable goal.
Plaque assessment
Patients should be encouraged to maintain an effective level of plaque control by brushing twice daily with a fluoride toothpaste. It is essential to monitor and record a patient's oral hygiene so that specific advice, relevant to an individual's particular needs, can be given.
Preventive strategy
In addition to dietary advice, the dental team has two other ways to prevent or control dental caries which will be discussed below:
Topical fluoride application; and
Fissure sealing.
The choice of these preventive agents will depend on several factors, namely:
Age of the individual;
Perceived caries risk;
Compliance;
Exposure to other fluoride delivery systems;
Medical and psychological factors which represent an increased caries risk.
Monitor outcome by recalling at intervals
Caries risk status is gauged by monitoring progress at intervals determined by caries risk status.
Topical fluoride agents
Fluoride toothpastes
Fluoride toothpastes are the most common means of delivering fluoride and in most countries comprise 98% of toothpastes available in retail outlets. Fluoride toothpastes reduce caries in the primary and permanent dentitions by up to 37% and 24%, respectively.29 The effectiveness of fluoride toothpastes can be increased by a range of factors.
Age at commencement of brushing
The younger the age at which brushing with a fluoride toothpaste commences, the lower the proportion developing caries.30 Of children whose carers reported starting brushing before the age of one year, 12% had some caries experience compared with 19% of those who started between one and two years of age.
Supervised toothbrushing
One-year-old children who had parental help with toothbrushing had less caries at two and three years of age.31 A systematic review concluded that supervised brushing increases the prevention of caries by a further 23% when compared to non-supervised brushing.32
Frequency of brushing
Numerous studies indicate that individuals who reported brushing twice a day or more had less caries than those brushing once a day or less. It was concluded that brushing twice a day provides a further 14% reduction compared with once a day.29
Timing of toothbrushing
Children's teeth should be brushed last thing at night and on one other occasion. Brushing last thing at night allows fluoride concentration levels to remain high during the night as salivary flow rates are lower during sleep.33
Fluoride concentration
The effectiveness of fluoride toothpaste is concentration dependent. It has been calculated that over the range 1000–2500 ppm F there is a further 8% improvement in efficacy for every 1000 ppm F and vice versa.29
Different countries vary in the recommendations for children aged less than 6 years when the swallowing of too much toothpaste, particularly in fluoridated areas, increases the risk of fluorosis. The Department of Health and the British Society for the Study of Community Dentistry have published an Evidence-Based Toolkit for Prevention34 and their recommendations for young children are as follows:
Children from 0–3 years are recommended to use a smear of toothpaste containing no less than 1000 ppm F;
From 3–6 years a pea-sized amount of toothpaste, containing 1350–1450 ppm F, should be used.
Higher strength toothpastes, containing 2800 and 5000 ppm F, are available in some countries and are prescription only medicines. Toothpaste containing 2800 ppm F may be advised for high caries risk individuals aged 10+ years and 5000 ppm F for those aged 16+ years. They are particularly useful for individuals with extensive caries, root caries and older patients with exposed root surfaces and reduced salivary flow.35 It is important to remind parents that rinsing with a large volume of water after brushing is associated with a reduction in the benefit of fluoride toothpaste.36
Fluoride mouthrinses
Fluoride mouthrinses may be used as an adjunct to the use of fluoride toothpaste in high caries risk individuals. They are not recommended for children less than 6 years of age. Rinses are produced in two formulations; 0.05% for daily application and 0.2% for weekly application. A Cochrane Systematic Review concluded that fluoride rinses reduce caries in the permanent dentition by 26%.37 They may be indicated particularly for orthodontic patients and special needs patients with poor dexterity. Ideally, the rinse should be used daily and at a different time from brushing in order to maintain the concentration of fluoride in plaque throughout the day.
Fluoride gels
A Cochrane Systematic Review concluded that the professional application of fluoride gels in trays, for approximately 5 minutes up to four times a year, reduces caries in the permanent dentition by 28%.38 Suction should be used to evacuate the excess material since the trays contain a high concentration (12,300 ppm) of fluoride. The application of fluoride gel necessitates a level of patient co-operation which precludes their use in very young patients.
Fluoride varnish
The application of fluoride varnish three times a year reduces caries in the deciduous and permanent dentitions by 33% and 46%, respectively.39 The varnish is cheap, quick and easy to apply, well tolerated, and does not require sophisticated facilities. Fluoride varnish can now be applied by appropriately trained health professionals, other than dentists, which broadens the opportunity for its use and provides a quick and simple way to apply topical fluoride.
Combinations of topical fluorides
The question arises as to whether fluoride mouthrinse, gel or varnish enhance the effectiveness of fluoride toothpaste. A systematic review analysed nine relevant studies and concluded that a combination of fluoride toothpaste with any one of the other three topical fluorides reduced caries in the permanent dentition by a further 10%, when compared with fluoride toothpaste alone.40 Patients should, therefore, be given the benefit of advice about the options available.
Fluoride tablets and drops
Fluoride from tablets and drops is ultimately swallowed and, therefore, increases the potential risk of fluorosis.41 Consequently, their use in many countries is not recommended, although they still have a place in preventive care for high caries risk and medically compromised individuals. The appropriate regime will be influenced by the age of the child and the use of other fluoride delivery vehicles. The tablets should be sucked to deliver the benefits of topical fluoride and used at a different time of day from toothbrushing.
Pit and fissure sealants
Fissure sealants are effective in reducing caries in the occlusal surfaces of permanent molars.42 A systematic review43 concluded that:
There was only limited evidence to support the placement of sealants on deciduous molars;
Retention is enhanced by the careful isolation of teeth;
The use of resin-based sealants is preferred to glass ionomer cement sealants;
Sealants should not be placed on partially erupted teeth or those with frank cavitation.
A meta-analysis concluded that sealants are effective in preventing the progression of caries in permanent teeth with non-cavitated carious lesions.44 It was suggested that sealants, when retained, block access to fermentable substrates and prevent bacteria exerting their cariogenic potential.45 There is some evidence that pit and fissure sealants are superior to fluoride varnish in the prevention of caries on occlusal surfaces,46 but they take longer to apply, requiring meticulous attention to the control of moisture on the etched enamel surfaces. After placement, the retention of sealants should be regularly monitored and reapplied, if necessary.
Health literacy
Dental attendance, oral health and general health are determined to a large extent by an individual's social environment, including income, employment, social support and education. The dental team should offer advice and support to help patients counteract some of these determinants of oral health through improving knowledge about looking after the mouth. Literacy may be defined as ‘the ability to understand and employ printed information in daily activities in order to achieve one's goals and develop one's knowledge potential’.47 The importance of literacy should not be underestimated, as it not only affects health, but impinges on our ability to gain employment and higher qualifications, so that one could argue that literacy is one of the main features that determines income.
Poor health literacy is associated with lack of attendance for health screening, increased hospitalization rates and later stages of cancer diagnosis.48 Having reasonable literacy skills helps patients to obtain the most from a healthcare system. Health professionals in general tend to overestimate the reading skills of patients. For example, a recent survey49 showed that around 20% of Americans and 17% of Canadians have reading difficulties. This is an important finding as the use of advice leaflets is widespread in dental practice and many of the publications used may be too difficult for patients to read. Patients who have poor literacy skills may also be reluctant to admit that they have problems understanding advice and reading follow-up literature. These patients want simple, one topic verbal advice, and leaflets must be largely pictorial and relate closely to the initial advice offered.
The key elements to effective dental health education are:
Try to categorize your patient in terms of his/her reading ability – this will be related to employment history and tertiary education;
Deal with one topic at a time, focusing on the key problem area for that particular patient;
Reinforce the information at subsequent visits;
Offer leaflets which will help patients remember what you have said, but make sure that they are not difficult to read and any illustrations are self-explanatory. A single ‘all purpose’ leaflet is unlikely to be effective.
Be prepared for failure – changing behaviour is difficult and will not be achieved in one advice session.
The profession has important dental health education messages50 which will help patients to maintain or improve their oral health. Keep the messages simple: too many messages cause distraction and confusion.
Conclusion
The objective of this paper has been to present an overview of the evidence-based messages that the dental team can offer patients in general practice.
The next paper will use case studies to consider the appropriateness of specific preventive advice for different patients.
