Dietary Fluoride Supplementation

Recommendations on the prescription of dietary fluoride supplementation for caries prevention were modified in 2010.¹ Dietary fluoride supplementation should be prescribed only for children who are at high risk of developing caries and whose primary source of drinking water is deficient in fluoride. Therefore the first step for the clinician is to determine if the child is at high risk as described in Chapters 13 and 14. If the child is at high risk and drinks water that is deficient in fluoride, then fluoride supplementation should be considered (Table 19-1).

By age 3 years, most children are able to chew and swallow tablets; therefore prescriptions for supplemental fluoride should be changed accordingly to reflect this change in developmental status. The recommended supplemental fluoride dosage schedule also requires an increase in the amount of fluoride prescribed after a child reaches 3 years of age. The recommended daily dosage of supplemental fluoride is 0.5 mg for children aged 3 to 6 years who drink water containing less than 0.3 ppm of fluoride. The dosage is 0.25 mg for those whose water contains between 0.3 and 0.6 ppm fluoride. Children whose drinking water contains more than 0.6 ppm of fluoride do not require any supplementation. Although the potential for producing dental fluorosis on permanent anterior teeth will have diminished in this age group owing to substantial crown formation, the practice of analyzing samples of each child’s drinking water before prescribing supplemental fluoride should continue. Analysis can be requested from the local public health department, family dentist, or commercial laboratories.

Because parental compliance continues to play a key role in determining the effectiveness of these supplements, efforts to reinforce parental motivation should be made. One method of assessing parental compliance is to monitor the need to rewrite supplemental fluoride prescriptions at recall visits. The dosage of fluoride prescribed should be noted in each patient’s record whenever a prescription is written. Parents who indicate no need for an additional prescription when the patient’s record suggests that the previously prescribed supplement should have been consumed should be questioned about the number of tablets remaining. A large existing supply suggests poor compliance during the period before the recall visit.

Topical Fluoride Therapy

Topical fluorides have an increasingly important role in the 3- to 6-year-old group. The child’s ability to use fluoride dentifrices increases throughout this period, although restraint in the amount of toothpaste used at each brushing should continue. Professional topical applications are often initiated during this interval and should be based on caries risk assessment. One mode of topical application that is generally not recommended for the younger members of this age group is the use of fluoride mouth rinses, because most preschoolers are unable to avoid swallowing some of these solutions.

Professional Applications OF Fluoride

Topical application of highly concentrated forms of fluoride has been provided in clinical settings for many years. The most commonly used agents include 8% to 10% solutions of stannous fluoride as well as 2% sodium fluoride and 1.23% acidulated phosphate fluoride (APF); the latter two compounds are available in solution, gel, and foam formulations. Numerous studies conducted before 1980 reported caries reductions averaging approximately 30% following use of these agents.2,3 However, several studies, including a large-scale national demonstration program⁴ have reported a more limited effect from semiannual applications of these agents (i.e., caries reductions of roughly 25%), especially in areas with fluoridated water.⁵ Fluoride varnish (Figure 19-1) has become a popular topical agent for preschool children and children with special health care needs, and it has been recommended for conditions in which decalcified enamel secondary to poor plaque removal or poor feeding practices is present.^6–8

Indications for Professional Topical Fluoride Applications

The questions of when and for whom topical application of fluoride should be provided in the dental office have been a source of some controversy. One school of thought invokes the argument that professional fluoride application is a primary preventive measure and should be provided to all children to minimize the potential for development of new carious lesions. Part of the historical basis for this approach relates to the lack heretofore of validated methods to predict whether an individual patient is likely to develop caries. Advocates of this philosophy tend to focus only on the potential benefits that might be achieved from topical fluoride application while ignoring the costs associated with providing the service.

Others feel that the decision to provide topical fluoride therapy should be based on the factors that have been shown to be associated with the risk of developing caries in groups or in individuals (e.g., access to fluoridated drinking water, use of other forms of topical fluoride, degree of spacing between teeth). Their approach is to consider the likelihood that each patient develops disease according to these factors and then to recommend professional topical fluoride therapy for those considered to be at significant risk for developing caries. Proponents of this philosophy tend to consider the costs associated with providing the service as well as the potential benefits.

The validity of the second approach obviously depends on the degree of accuracy with which one is able to predict which persons are more likely to experience caries. As methods of caries prediction are refined over time, the argument for individualizing preventive treatments is likely to become increasingly compelling.

Cost-Benefit Considerations

In a private practice setting the patient’s willingness or ability to pay for different forms of treatment usually is an important factor in determining what types of services are provided. In the case of public programs or private third-party payors, the decision to provide reimbursement for various services may be based on a more formal analysis of the relationship between the costs and benefits associated with those services. The ratio of costs to benefits has historically been higher for topical fluoride applications provided in dental offices than for other types of preventive services or for the same services provided in other settings. Consequently, professional topical fluoride treatments have not been recommended as a public health measure because of their unfavorable cost/benefit ratio. Documented changes in caries levels and patterns of decay in children in the United States have pushed these ratios even higher. Studies have reported that a substantial proportion of school-aged children in the United States are caries free and that a relatively small percentage of children account for a large percentage of all tooth decay.⁹ In addition to the overall decline in the level of caries, there has been a decrease in the proportion of smooth-surface caries and a corresponding increase in the proportion of pit and fissure caries. The combination of these factors seems to be associated with a reduction in the effectiveness of concentrated topical fluoride therapy in terms of the actual number of surfaces saved from becoming carious during a given period.³

Changes of this nature have led some interested parties to call for a reexamination of the manner in which various preventive measures are provided. In an era when increased attention is being focused on measures for controlling all types of health care costs, some have proposed that consideration be given to making preventive dental services more cost-effective. One means of improving the cost/benefit ratio of topical fluoride therapy would be to provide this therapy in settings other than dental offices (e.g., at school or in the home) by self-application techniques. Another previously mentioned method that could also apply to preventive services provided in dental offices would be to identify patients who are more likely to develop caries and target preventive services to those individuals.

A factor that has been repeatedly demonstrated to be associated with a reduction in both the risk of developing caries and the relative effectiveness of topical fluoride therapy is the availability of drinking water containing fluoride. Studies have shown that topical fluorides are considerably more effective in reducing the incidence of decay in nonfluoridated areas compared with fluoridated areas.⁵ Therefore, the cost of preventing a carious lesion in a fluoridated area by means of professional topical fluoride therapy is significantly greater than the cost of preventing a lesion in a non-fluoridated area. From a cost-benefit perspective, this suggests that in fluoridated areas topical fluoride treatments should be reserved for patients who have a history of moderate to high caries development or who are in proven high-risk categories. Those who do not seem to be particularly prone to developing caries, especially smooth-surface decay, would probably benefit more from other forms of prevention such as occlusal sealants.

The question of which preventive services should be provided for a particular child in the dental office remains an individual issue for dentists and their patients (or parents in the case of children). Accordingly the final decision about professional preventive services must be based on the child’s risk assessment and made by the child’s parents once informed on the costs and expected benefits. However, the influence of third-party coverage for different types of services can significantly affect this decision and ultimately the care received by the child.

Presently the recommendations for professionally applied topical fluoride are that children 3 to 6 years old at moderate risk should receive topical fluoride applications every 6 months. Those children with high caries risk should receive the treatments more frequently (i.e., every 3 to 6 months)¹⁰ (Table 19-2).