Benefits and risks of fluoride supplementation: caries prevention versus dental fluorosis

The effect of professional fluoride application program for preschool children in Taiwan: An analysis using the National Health Insurance Research Database (NHIRD)

Background/Purpose

Dental caries in primary dentition is a major public health problem in many countries, as well as Taiwan. The service of professional topical fluoride application for children under 5 years of age, performed twice a year by the BNHI in Taiwan through the “Preventive Dental Health Service for Children” plan, began in July 2004. The purpose of this study was to examine the effect and trend of professional topical fluoride application on dental utilization.

Materials and methods

The sample subjects were taken from the Normalized Million People File of 2010 in the National Health Insurance Research Database from 2000 to 2012, for the purpose of analyzing the status of the professional topical fluoride program. The main analysis included utilization of professional topical fluoride application, utilization of restorative treatment and utilization of endodontic therapy in children 1-to-5-years of age. The Cochran–Armitage trend test was used for statistical analysis.

Results

Professional topical fluoride utilization increased year upon year, particularly after 2012 (P < .001). There was a tendency to reduce the utilization of endodontic therapy (P < .001). The severity of dental caries (number of times receiving dental restoration or endodontic therapy) was decreased after professional topical fluoride application was performed (P < .001).

Conclusion

Because the dental caries rate for preschool children in Taiwan remains high, it is beneficial to receive professional topical fluoride application for dental care, as this reduces the severity of dental caries and endodontic therapy needs.

Impact of 24-month fluoride tablet program on children with disabilities in a non-fluoridated country

The aim of this study was to evaluate the caries preventive effects of a school-based fluoride tablet program in children with disabilities. Two hundred and seventeen children with disabilities were divided into two groups: the intervention group (IG) ingested 1.0mg fluoride tablet daily while the control group (CG) ingested a placebo. The initial oral examinations were conducted prior to fluoride intake and 24-month follow-up examinations were conducted to evaluate the effectiveness of fluoride tablet ingestion. The results from this study demonstrated significant reductions in the DMFT index (the sum of decayed, missing, and filled permanent teeth), 0.63, as well as the DMFS index (the sum of decayed, missing, and filled surfaces of the permanent dentition), 1.25, when compared with the CG. A statistically significant reduction in the DMFT index and DMFS index (30.42% and 36.84%, respectively) suggested an anti-cariogenic benefit to fluoride tablet administration. Greater caries reduction occurred on mesio-distal and bucco-lingual surfaces (53.27% and 52.57%, respectively). Fluoride tablets should be considered as a caries preventive strategy in school-based caries prevention programs for children with disabilities in fluoride deficient areas.

Urinary fluoride concentration in children with disabilities following long-term fluoride tablet ingestion

Urine is the most commonly utilized biomarker for fluoride excretion in public health and epidemiological studies. Approximately 30-50% of fluoride is excreted from urine in children. Urinary fluoride excretion reflects the total fluoride intake from multiple sources. After administering fluoride tablets to children with disabilities, urinary fluctuation patterns should be investigated. The purpose of this study was to monitor the short and long term fluctuating patterns of urinary fluoride concentration after fluoride tablets were ingested by children with disabilities. Children with disabilities aged 6-12 years old were selected randomly and were divided into three groups: Group A, 1.0mg fluoride tablet, Group B, 0.5mg fluoride tablet, and Group C, control group. The urine samples were collected in the morning (MU) and 2h after fluoride tablets were ingested (AU). Urine was collected on the day prior to fluoride intake (baseline), the first, the third, the fifth and the eighth day of fluoride ingestion for a short term, and once every 6 months for a total of 18 months for long-term observation. The AU sample showed statistically significantly higher concentrations of urine fluoride than those of the MU samples, and no statistically significant difference was noticed in the MU samples among the three groups. Group A showed the highest urinary fluoride concentration (UFC) among the three groups. UFC increased as ingested fluoride tablet dosage increased, and it returned to the baseline level on the following day and persisted throughout the study period.

Topical fluoride as a cause of dental fluorosis in children

BACKGROUND

For many years, topical use of fluorides has gained greater popularity than systemic use of fluorides. A possible adverse effect associated with the use of topical fluoride is the development of dental fluorosis due to the ingestion of excessive fluoride by young children with developing teeth.

OBJECTIVES

To describe the relationship between the use of topical fluorides in young children and the risk of developing dental fluorosis.

SEARCH STRATEGY

Electronic search of the Cochrane Oral Health Group Trials Register, CENTRAL, MEDLINE, EMBASE, BIOSIS, Dissertation Abstracts and LILACS/BBO. Reference lists from relevant articles were searched. Date of the most recent searches: 9th March 09.

SELECTION CRITERIA

Randomised controlled trials (RCTs), quasi-RCTs, cohort studies, case-control studies and cross-sectional surveys, in which fluoride toothpastes, mouthrinses, gels, foams, paint-on solutions, and varnishes were compared to an alternative fluoride treatment, placebo or no intervention group. Children under the age of 6 years at the time topical fluorides were used.

DATA COLLECTION AND ANALYSIS

Data from all included studies were extracted by two review authors. Risk ratios for controlled, prospective studies and odds ratios for case-control studies or cross-sectional surveys were extracted or calculated. Where both adjusted and unadjusted risk ratios or odds ratios were presented, the adjusted value was included in the meta-analysis.

MAIN RESULTS

25 studies were included: 2 RCTs, 1 cohort study, 6 case-control studies and 16 cross-sectional surveys. Only one RCT was judged to be at low risk of bias. The other RCT and all observational studies were judged to be at moderate to high risk of bias. Studies were included in four intervention/exposure comparisons. A statistically significant reduction in fluorosis was found if brushing of a child's teeth with fluoride toothpaste commenced after the age of 12 months odds ratio 0.70 (random-effects: 95% confidence interval 0.57 to 0.88) (data from observational studies). Inconsistent statistically significant associations were found between starting using fluoride toothpaste/toothbrushing before or after the age of 24 months and fluorosis (data from observational studies). From the RCTs, use of higher level of fluoride was associated with an increased risk of fluorosis. No significant association between the frequency of toothbrushing or the amount of fluoride toothpaste used and fluorosis was found.

AUTHORS' CONCLUSIONS

There should be a balanced consideration between the benefits of topical fluorides in caries prevention and the risk of the development of fluorosis. Most of the available evidence focuses on mild fluorosis. There is weak unreliable evidence that starting the use of fluoride toothpaste in children under 12 months of age may be associated with an increased risk of fluorosis. The evidence for its use between the age of 12 and 24 months is equivocal. If the risk of fluorosis is of concern, the fluoride level of toothpaste for young children (under 6 years of age) is recommended to be lower than 1000 parts per million (ppm).More evidence with low risk of bias is needed. Future trials assessing the effectiveness of different types of topical fluorides (including toothpastes, gels, varnishes and mouthrinses) or different concentrations or both should ensure that they include an adequate follow-up period in order to collect data on potential fluorosis. As it is unethical to propose RCTs to assess fluorosis itself, it is acknowledged that further observational studies will be undertaken in this area. However, attention needs to be given to the choice of study design, bearing in mind that prospective, controlled studies will be less susceptible to bias than retrospective and/or uncontrolled studies.

Practitioner's guide to fluoride

The current health care trend is to provide evidence-based recommendations and treatment. Many literature reviews have shown fluoride's effectiveness against caries. The current use of fluoride in the prevention of dental caries is based on community, professional, and individual strategies. Personalized fluoride regimens should include a risk analysis and a review of the patient's current fluoride exposure. The future of fluoride may be found in its slow release and retention in the oral cavity through various modalities. Because of the many uncertainties still associated with fluoride, further research is needed.

The case for reducing the current Council on Dental Therapeutics fluoride supplementation schedule

The milder forms of dental fluorosis have increased in prevalence since the original epidemiologic surveys of the 1930s. Most studies of fluorosis have identified the use of supplements as a major risk factor. Fluorosis could be prevented, in part, by stopping the improper prescription of fluoride supplements in optimally fluoridated areas and by lowering the dosage currently recommended by the Council on Dental Therapeutics supplemental fluoride schedule. At a 1991 workshop at the University of North Carolina, five alternatives to the present ADA Council on Dental Therapeutics schedule were suggested; however, no consensus on dosage was reached. Recently, the Fédération Dentaire International adopted a dosage schedule of 0.25 mg F from birth to 3 years of age, 0.5 mg F from 3 to 5 years, and 1 mg F thereafter. At a 1992 Canadian workshop it was proposed that supplements should not be started until age 3, should be given only to those "at high risk" of caries, and only 0.25 mg F should be prescribed from 3 to 5 years of age. Similarly, in some European countries supplements are not recommended until 3 years, at which time 0.5 mg F is prescribed, but only "for children at risk." Australia is considering a dosage schedule starting with 0.25 mg F at 6 months, again only for those "particularly at risk of caries." Serious problems exist in limiting fluoride supplementation only to high-caries-risk children because they are not easily identifiable at a young age. Ideally, a dosage schedule should be based on body surface area or weight rather than simply age, and supplements should be in the form of lozenges for children over 2 years of age. A reduced fluoride supplement dosage schedule is proposed.

The case for eliminating the use of dietary fluoride supplements for young children

Fluoride supplements have been used for years to prevent dental caries; nevertheless, there are three reasons why their use is inappropriate today among infants and young children in the United States. Evidence for the efficacy of fluoride supplements when used from birth or soon after is weak, supplements are a risk factor for dental fluorosis, and fluoride has little preeruptive effect in caries prevention. While there are many reports on the caries-preventive efficacy of supplements, few meet standards for acceptability as clinical trials, and those that do have tested chewable tablets or lozenges under supervision in school-aged children. North American children today are exposed to fluoride from many sources--drinking water, toothpaste, gels, rinses, and in processed foods and beverages. The additional cariostatic benefits that accrue from using supplements are marginal at best, while there is strong risk of fluorosis when young children use supplements. Available evidence suggests that the public is more aware of the milder forms of fluorosis than was previously thought; thus, it is prudent for caries-preventive policies to aim to maximizing caries reductions while minimizing the risk of fluorosis. It is therefore concluded that the risks of using supplements in infants and young children outweigh the benefits. Because alternative forms of fluoride for high-risk individuals exist, fluoride supplements should no longer be used for young children in North America.

"Risk periods" associated with the development of dental fluorosis in maxillary permanent central incisors: a meta-analysis

This systematic review of the dental literature (1966-98) concerns risk periods associated with dental fluorosis in the maxillary permanent central incisors. A literature search was organized through the MedLine and the ISI databases. In addition, one unpublished paper (in manuscript) was obtained, as well as one paper published before 1966. However, out of 143 catches, only 10 studies were included in this review. The main reason for exclusions was that the data presented did not meet the criteria given for the present meta-analysis. Among the included papers, 7 pertained to subjects whose exposure to fluoride started at different ages during the enamel formation (Group 1), and 3 were based on subjects who had been exposed from birth and then experienced an abrupt reduction in daily fluoride exposure at different ages during the amelogenesis period (Group 2). The meta-analysis for Group 1 found the odds ratio (OR) for dental fluorosis in children exposed to fluoride early in life (before 2 years of age) to be 7.24 (95% CI; 4.71-11.13) as compared to children exposed later in life (after 2 years of age). The meta-analysis for the studies in Group 2 found the overall OR to be 1.88 (95% CI; 1.35-2.61) for children who had a reduction in fluoride intake after 2 years of age, as compared to individuals who experienced reduction earlier (during the first 2 years). The studies from both groups were pooled and the duration of exposure to fluoride during the first 4 years of life was the independent variable. The meta-analysis now revealed an overall OR of 5.83 (95% CI; 2.83-11.94) for long periods of fluoride exposure (>2 out of the first 4 years) versus shorter periods of exposure (<2 out of the first 4 years of life) during the enamel formation in the maxillary central incisors. Based on the findings of the meta-analysis, no specific period of enamel formation is singled out as being the most critical for the development of dental fluorosis. The duration of fluoride exposure during the amelogenesis, rather than specific risk periods, would seem to explain the development of dental fluorosis in the maxillary permanent central incisor.

Fluoride supplements and fluorosis: a meta-analysis

This paper presents a systematic review of the dental literature that was carried out to investigate whether the regular use of fluoride supplements in non-fluoridated communities during the period of tooth development increases the risk of dental fluorosis. A MEDLINE search was organized for all documents published, in English, between January 1966 and September 1997 using the following key words: fluorosis, dental, fluoride, fluoride supplement or supplements, drop or drops, and tablet or tablets. Twenty-four studies that assessed the development of dental fluorosis in children who had used fluoride supplements earlier in their life were included in this review. Of the 24 studies, 10 were cross-sectional/case control studies and four were follow-up studies. These studies had data that allowed a quantitative estimation of the risk of developing dental fluorosis in users of fluoride supplements. The other 10 studies were excluded because they either did not present enough data or had other methodological problems. A qualitative review of the studies found a consistent and strong association between the use of fluoride supplements and dental fluorosis. The meta-analyses of the cross-sectional/case-control studies estimated that the odds ratio of dental fluorosis in users of fluoride supplements compared with non-users ranged between 2.4 and 2.6. The meta-analyses of the follow-up studies estimated that the relative risk in long-term users was between 5.5 and 12.2. This review confirmed that in non-fluoridated communities the use of fluoride supplements during the first 6 years of life is associated with a significant increase in the risk of developing dental fluorosis.