Preventing Dental Caries in Children at High Caries Risk
Section 3: Primary prevention of dental caries

Keeping children's teeth healthy before disease occurs

Assessing caries risk is important for all patients and the process has to be repeated at intervals. Caries-promoting factors may change between visits and on a population level the disease and its sequelae are very widespread in adulthood. This guideline seeks to identify those children who are at greatest risk of future dental decay in time to prevent the ravages of dental caries. However, it must be appreciated that primary prevention will be required in all children to maintain low caries risk status.

A large and comprehensive evaluation of caries risk assessment has demonstrated that, although there are limits to the sensitivity and specificity attainable, practical caries risk assessment in this age group is achievable.8, 9 Evidence level IIb

3.1 Risk factors for dental caries

There are a wide range of overlapping factors to consider when assessing an individual's degree of risk from this multifactorial disease. The risk factors described below and summarised in Table 1 were identified from the systematic review undertaken for the Faculty of General Dental Practitioners guidelines on selection criteria for dental radiography.9 Additional evidence for the importance of these risk factors is cited in the following sections.

3.1.1 Previous disease

Past caries experience is the most powerful single predictor of future caries increment (but even so the power is modest). When screening for high caries increment in young children (aged six years), caries in deciduous teeth is a better criterion than caries in permanent first molars.10 Evidence level IIb

3.1.2 Diet

Sugars are a major component of our daily diet. Children average nearly seven intakes of food per day,11, 12, 13 many of which are snacks rich in added sugars. Although there are many risk factors for dental caries, the local effect of dietary sugars has a fundamental role in the disease. Evidence level III

The 1945-1953 Vipeholm study14 is one of the largest single studies investigating the association between sugar consumption and dental caries. It concluded that consumption of sugary food and drinks both between meals and at meals is associated with a large caries increment. For ethical reasons, this study has never been repeated but the conclusions have been ratified by more recent national reports. 15, 16 Evidence level IIa

Several dietary factors are associated with caries incidence:

However, the key observation is that increasing the frequency of sugar intake increases the odds of developing dental caries, whilst lowering sugar intake can reduce it. 11, 12, 13, 14, 15, 16, 17, 18, 19 Evidence levels II and III

3.1.3 Social factors

Studies have demonstrated that dental caries is most prevalent in schoolchildren from low socio-economic status families. Children from these families show higher caries prevalence, fewer caries-free teeth, fewer sealants and more untreated lesions.20, 21 Evidence level III

3.1.4 Use of fluoride

Consideration of water fluoridation as a public health measure is beyond the scope of this guideline, which seeks to make recommendations for those presenting in dental practice. However, there is strong evidence for its efficacy and safety from studies spread over many years22 and fluoridation has been shown to have a particularly beneficial effect on high caries risk, deprived children.20 A rigorous systematic review has recently been published by the NHS Centre for Reviews and Dissemination. Evidence level IIa and III

The use of fluoride in tooth protection is considered in sections 3.3.2 and 3.4.

3.1.5 Plaque control

Removal of bacterial plaque is important in minimising one of the aetiological factors in caries. Health benefits are, however, primarily due to the incorporation of fluoride into most toothpastes (see section 3.3.2).

3.1.6 Saliva

Saliva fulfils a major protective role against dental caries. A small group of children in this age group may have reduced salivary flow - usually as a consequence of their medical history and related drug therapy (see section 5) - and are at high risk of dental caries.

3.1.7 Medical history and disability

A range of factors in a child's medical history may be associated with increased caries risk (see section 5).

A learning disability is not, per se, a predictor of increased caries risk.23 However, a wide variety of physical and learning disabilities result in decreased ability to perform oral self-care. Learning disability is often associated with poor oral hygiene and frequent consumption of sweet snacks. In this group of patients caries is often untreated and extraction rates are higher.24 Evidence level IIb

Some disabled patients are resident in institutions where carers are responsible for their oral hygiene. Clinicians should therefore be aware of the need to provide appropriate preventive care to individuals within these groups. These disabilities may also make dental treatment difficult and general anaesthesia may be required.

Table 1: Assessing caries risk

(Adapted from the table compiled by Professor Edwina Kidd for the Faculty of General Dental Practitioners guidelines on selection criteria for dental radiography.9)

3.1.8 Caries risk assessment

For individual patients, the objective clinical judgement of the dentist, their ability to combine and use these risk factors and their knowledge of the patient has been shown to be one of the most powerful predictors of that individual's caries risk.25 In particular, the dentist's subjective judgement of the size of the 'Decayed', 'Missing' and 'Filled' increment (newly developing caries) over subsequent years is also a relatively strong predictor.8 Evidence level IIb and IV

3.2 Identifying children at high caries risk

Given the pattern of development of dental caries and its widespread prevalence in adulthood, most children are "at risk" of dental caries. However, the focus of this guideline is to target those at high caries risk in time to avoid the repeated and increasingly severe and costly consequences of the disease. This targeting requires identification of those individuals who are at increased risk of developing dental caries.

The risk factors for dental caries and a recommended simple risk categorisation are summarised in Table 1. This concept of risk assessment is fundamental to the implementation of this guideline

3.3 Behaviour modification in high caries risk children

3.3.1 Dental health education

The goal of dental health education is to establish good oral hygiene and dietary habits. The dental and allied professions have an ethical responsibility to inform patients about disease and how to prevent it.

The establishment of needs-related oral hygiene habits requires long-lasting motivation. The most important motivational factor is a feeling of individual responsibility based on self-diagnosis and behavioural principles.26 Evidence level Ib

A systematic review has demonstrated that dental health education carried out by a professional at the chairside is more often effective than other types of oral health promotion interventions. However, oral health promotion per se has not been shown to be effective for caries prevention unless fluoride is utilised in the intervention.27 Evidence level Ia

This is a controversial area as, in spite of the importance of the area, some issues have been poorly researched28, 29 and there are design challenges around the use of randomised controlled trials29 which may favour oral health education over broader oral health promotion strategies. However, given that high caries risk patients are presenting in the dental surgery, the following recommendations can be made:

(See Annex 2 for sources of further information and patient education materials.)

3.3.2 Oral hygiene

The value of toothbrushing in caries prevention lies with the regular topical application of fluoride.

Toothpastes containing fluoride at 1000-2800 parts per million (ppm) have been shown to be effective in preventing dental caries in children aged between six and 16 years.30, 31 Children who brush twice a day show greater benefit than those who brush less frequently. In addition, rinsing the mouth with a beaker of water after brushing reduces the efficacy of the fluoride toothpase in the prevention of caries and recurrent caries compared with less diluting methods of clearing the mouth.32, 33 Evidence level Ib

The report of the dental public health consultants in Scotland recommends that adults and children over seven years should: 34

In children up to seven years of age the report recommends the use of only a smear or small pea-sized quantity of toothpaste and encourages children to spit out toothpaste after brushing. Swallowing toothpaste is discouraged, as is active rinsing out after brushing. The Health Education Authority makes similar recommendations.35 Evidence level IV

Considerations about fluoride dosages for infants are outwith the scope of this guideline.

3.3.3 Diet and sugar consumption

As discussed in section 3.1.2, lowering sugar intake reduces the incidence of caries in children.11, 12, 13, 14, 15, 17, 18, 16, 19 A Brazilian study has shown that the incidence of approximal lesions in 12 year olds can be reduced by diet and oral hygiene training.36 Limiting the ingestion of refined carbohydrate to meal times is also widely recommended.37 Evidence level III and IV

3.3.4 Xylitol

Although there is little evidence on the anti-caries effects of other non-sugar sweeteners, a series of studies in Finland have demonstrated that substitution of xylitol for sugar in the diet results in very much lower caries increments.38 Evidence level III

3.3.5 Sugar-free chewing gum

Chewing gums containing xylitol and sorbitol have anti-caries properties through salivary stimulation. Xylitol is more effective than sorbitol in caries reduction, as it also has antibacterial properties.39 Evidence level IIb

3.3.6 Sugar-free medicines

Until fairly recently, medicines intended for children have been highly sweetened to make them easier to administer. Little attention was given to the danger to teeth from frequent consumption of sweetened medicines. However, concerns over iatrogenic damage to children's teeth have resulted in the widespread availability of sugar-free alternatives for most paediatric medications.40, 41, 42, 43 Evidence level III

See section 5.4 for further information for non-dental professionals on the use of sugar-free medicines.

3.4 Tooth protection in children at high caries risk

3.4.1 Sealants

The use of resin pit and fissure sealants has been shown to be an effective barrier method of preventing caries in pits and fissures over a wide range of studies in recent decades. Improvements in dental materials have increased retention and improved technique sensitivity in high caries risk patients. A formal meta-analysis has demonstrated their efficacy. 44 Evidence level Ia

The selection of patients who will benefit most from the application of sealant is based on the risk of caries.45 Factors that should be considered include medical history and previous caries experience (see Table 1). For the majority of "at risk" individuals sealing permanent molars is sufficient. However in high risk patients all pits and fissures should be sealed.45 Details of patient selection and also tooth selection are given in the British Society of Paediatric Dentistry policy document45. Evidence level IV

For optimal efficiency, the sealant should be present in all affected pits and fissures. The condition of the sealant should be reviewed regularly with further coatings added as required.46, 47 Evidence level IIa

Glass ionomer sealants have poorer retention than composite resin materials and their effect on caries reduction is equivocal. Therefore, glass ionomer sealants are mainly used when it is not possible to use a resin material, for example due to poor patient compliance.48 Evidence level IIa

3.4.2 Fluoride tablets

The few scientifically rigorous clinical trials of fluoride supplements undertaken to date, while confirming their caries-inhibiting potential, suggest that the actual contribution of fluoride supplements to caries prevention is slight as compliance amongst those most at risk is problematic.34 Evidence level IV

Fluoride supplements are no longer recommended routinely for caries prevention in children living in areas with little fluoride in water; nor should they be prescribed for those residing in areas with optimal levels of fluoride in the water. However supplements may still be considered for children with intractable caries risks.49 The report of the consultants in dental public health in Scotland34 states that additional fluoride supplements (1mg F, 2.2mg NaF per day50) are appropriate for high caries risk children and can be used where compliance is likely to be favourable. Evidence level IV

Fluoride supplements are available as tablets or as a mouthwash. An eight year school-based study of children initially aged five to six which compared weekly rinsing (0.2% neutral NaF solution) with chewing, rinsing with, and swallowing a tablet daily (2.2mg NaF), concluded that fluoride tablets were the best option.51 Evidence level IIa

Ideally, tooth brushing and tablet taking should occur at different times to permit the longest possible period for topical fluoride uptake from each fluoride source.

3.4.3 Topical varnishes

For high risk children where reliance on the home based use of fluoride toothpaste and tablets is deemed to be insufficient, professional application of a fluoride varnish may help to prevent dental caries.

A study in Chandigarh, India evaluated the professional application of 2% NaF solution, 1.23% acidulated phosphate fluoride solution (APF), or 2.26% F Duraphat at six-monthly intervals for 30 months in children aged 6-12 years. The largest reduction in caries increment was seen with Duraphat.52 However, the authors of this study highlighted the socio-cultural differences between Chandigarh and the West, and some caution may therefore be needed in extrapolating the results of this study to the Scottish population. Evidence level Ib

A similar study in Finland found no significant difference in three year caries increments in children (aged 12-13 years) who received six monthly applications of either 2.26% F Duraphat varnish or 1.23% APF gel.53 Evidence level IIb

Applying fluoride varnishes more frequently than twice a year does not provide additional caries protection in a population with relatively low caries activity. A study in Finnish children aged 9-13 years found no statistically significant difference in caries increments between two or four applications of Duraphat per year.54 Evidence level IIb

3.4.4 Chlorhexidine

A meta-analysis of clinical studies assessing the caries preventive effects of chlorhexidine has demonstrated that chlorhexidine prophylaxis in the form of a rinse, gel or paste can achieve a substantial (average 46%) reduction in caries irrespective of application method, frequency, caries risk, caries diagnosis, tooth surface, or fluoride regimen.55 Evidence level Ia

Professional flossing four times a year with chlorhexidine gel has been shown to lead to significant reductions in approximal caries. This quick (10 minutes) and effective measure can be used in patients with high caries activity to complement the use of sealants in protecting fissures.56 Evidence level IIa

In one study, a chlorhexidine varnish (e.g. Cervitec, 1%) was shown to be effective in preventing fissure caries when applied three times over nine months.57 An evaluation of a prototype 10% chlorhexidine varnish on Scottish teenagers using a regimen starting with four separate weekly applications followed by annual applications failed to show a significant benefit over conventional preventive care, but this may reflect the particular regimen or formulation used in this trial.58. Evidence level Ib and IIa

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