Risk factors for enamel fluorosis in optimally fluoridated children born after the US manufacturers' decision to reduce the fluoride concentration of infant formula

This case-control study investigated risk factors for enamel fluorosis in optimally fluoridated children, born after the US infant formula industry voluntarily reduced the fluoride content of their products. Analysis was performed on 233 children, aged 10-14 years. Case-control status was determined using the Fluorosis Risk Index (FRI). Risk factor exposure was ascertained via a mailed questionnaire. Logistic regression analyses revealed a strong association between mild-to-moderate enamel fluorosis on early forming (FRI classification I) enamel surfaces and both fluoride supplement use (odds ratio (OR)=5.95, 95% confidence interval (CI) 1.06-33.53), and early fluoride toothpaste use (OR=6.35, 95% CI 1.21-33.40). The authors found a suggestive, but nonsignificant, association between fluorosis on these enamel surfaces and infant formula in the form of powdered concentrate (OR=4.33, 95% CI 0.73-25.66). There was a strong association between mild-to-moderate fluorosis on later forming (FRI classification II) enamel surfaces and infant formula use in the form of powdered concentrate (OR=10.77, 95% CI 1.89-61.25), fluoride supplement use (OR=10.83, 95% CI 1.90-61.55), and early fluoride toothpaste use (OR=8.37, 95% CI 1.68-41.72). No association was observed between the use of ready to feed infant formula and enamel fluorosis.

Estimation of optimal concentration of fluoride in drinking water under conditions prevailing in Chile

The purpose of this comparative study of caries and dental fluorosis experience in Chilean children was to estimate the optimal range of fluoride concentration in tap water under conditions currently prevailing in Chile. The sample included 2431 schoolchildren 7, 12 and 15 years old, life-long residents of five communities with fluoride concentrations in their tap water in the range 0.07-1.1 mg/L. The study population received an oral clinical examination including caries experience and an enamel fluorosis evaluation of the permanent dentition (Dean's scoring system). For 15-year-old children, the DMFT index changed from 5.06 to 2.60, and for 12-year-olds it changed from 3.10 to 1.36 when fluoride water concentration changed from 0.07 to 1.10 mg/L. For 7-year-old children the dmft index correspondingly changed from 3.67 to 1.59. The relationship between DMFT for 12-year-olds and water fluoride concentration was best fitted by a logarithmic function (r2=0.98). The Community Fluorosis Index (CFI) was used to assess enamel fluorosis in the study population, and it showed a linear relationship (r2=0.983) with increasing fluoride concentration of water for the 12-year-old group. Results obtained suggest that under current Chilean conditions, the optimal range of fluoride concentration in potable water should lie in the 0.5-0.6 mg/L range.

[Water fluoridation in the Region of Murcia]

BACKGROUND

The purpose of this study is that of expounding upon the natural fluoride ion concentrations in the public water supplies of all of the municipalities in the Region of Murcia in 1991, in addition to the trend in said concentrations throughout the 1992-1996 period, this being a time during which fluoride was added to the water supply as a public health measure.

METHODS

The methods employed for the findings were those of potentiometer-based gauging by means of standard addition and direct findings using a potentiometer equipped with an ion-selective electrode.

RESULTS

The findings indicate that major fluctuations have taken place in the amounts of fluoride in these waters throughout the initial years during which fluoride was added to the water supply, without it being possible to establish broad-scope geographical patterns, to later tend toward stabilization during the final years of the time period in question, in which solely the municipalities supplied by the Letur treatment plant (which supplies the central and northwestern areas of the Region) showed levels nearing 0.8 mg/l, been maintained, which are those stipulated under the regulations resolving in favor of the addition of fluoride.

CONCLUSIONS

We can conclude that only a portion of the municipalities of the Murcia Region has reached the optimum value for the concentration of fluoride in drinking water proposed by the Autonomous Community (0.8 mg/liter), or values close to it (0.6-0.7 mg/liter) during the period studied.

[Evaluation of fluoride content of bottled drinking waters in Brazil]

The utilization of a systemic fluoride method must be controlled in terms of risks and benefits. The reason for this is that while a small dose will not be effective in preventing dental caries, a larger dose may cause dental fluorosis. Therefore the knowledge of the fluoride concentration found in the bottled mineral waters sold throughout the Brazilian market the consumption of which has increased lately, is of great concern. The objective of the study was the analysis of the concentration of fluoride found in the bottled mineral waters. A hundred and four brands coming from different regions of Brazil were analysed using an Orion 96-09 ion specific electrode and an Orion EA 940 ionanalyser. previously calibrated with standard fluoride solutions. Different concentrations of fluoride ranging from 0.0 to 4.4 were found. It was discovered that specific bottled waters contained: 1) Significant concentrations of fluoride not reported by the producer; 2) Fluoride concentrations of no preventive effect, although the producer had advertised the water as a Fluoridated Mineral Water; 3) Fluoride concentrations high enough to cause dental fluorosis, although the producer did not alert the consumer to this fact. It is to be concluded, therefore, that a sanitary regulatory system for the control of the level of fluoride in the bottled mineral waters marketed is necessary. Such reputation should be formulated in terms of benefits as well as in terms of risks.

Prevalence and severity of fluorosis in the primary and permanent dentition using the TSIF

This paper reports on the prevalence and severity of dental fluorosis in the primary and permanent teeth and the tooth surfaces of 262 school children aged 6-18 years from two communities in KwaNdebele (South Africa), the first with 8-9 ppm F-, and the second with 0.6-1.6 ppm F- in the drinking water. The Tooth Surface Index of Fluorosis (TSIF) was used to measure the degree of fluorosis. In both areas, the population prevalence, for primary and permanent teeth was more than 90 per cent. For the lower F- area, 40 per cent of tooth surfaces were free of fluorosis compared with only 22 per cent in the high F- area. Of the surfaces affected by fluorosis in the high F- area, 37 per cent scored in the categories 4-7, compared with 6 per cent in the lower F- area. This difference in severity was found to be statistically significant (P<0.001). This study has shown that, in two areas with significantly different levels of fluoride in the water supply, the population prevalences of fluorosis were similar, but significant differences existed in severity. The World Health Organization 1984 guidelines for Drinking-water Quality recommend that 1.5 ppm F- is the maximum acceptable concentration in drinking water but this may not be appropriate for South Africa.

Appropriate uses of fluorides for children: guidelines from the Canadian Workshop on the Evaluation of Current Recommendations Concerning Fluorides

OBJECTIVE

To prevent fluorosis caused by excessive fluoride ingestion by revising recommendations for fluoride intake by children.

OPTIONS

Limiting fluoride ingestion from fluoridated water, fluoride supplements and fluoride dentifrices.

OUTCOMES

Reduction in the prevalence of dental fluorosis and continued prevention of dental caries.

EVIDENCE

Before the workshop, experts prepared comprehensive literature reviews of fluoride therapies, fluoride ingestion and the prevalence and causes of dental fluorosis. The papers, which were peer-reviewed, revised and circulated to the workshop participants, formed the basis of the workshop discussions.

VALUES

Recommendations to limit fluoride intake were vigorously debated before being adopted as the consensus opinion of the workshop group.

BENEFITS, HARMS AND COSTS

Decrease in the prevalence of dental fluorosis with continuing preventive effects of fluoride use. The only significant cost would be in preparing new, low-concentration fluoride products for distribution.

RECOMMENDATIONS

Fluoride supplementation should be limited to children 3 years of age and older in areas where there is less than 0.3 ppm of fluoride in the water supply. Children in all areas should use only a "pea-sized" amount of fluoride dentifrice no more than twice daily under the supervision of an adult.

VALIDATION

These recommendations are almost identical to changes to recommendations for the use of fluoride supplements recently proposed by a group of European countries.

SPONSORS

The workshop was organized by Dr. D. Christopher Clark, of the University of British Columbia, and Drs. Hardy Limeback and Ralph C. Burgess, of the University of Toronto, and funded by Proctor and Gamble Inc., Toronto, the Medical Research Council of Canada and Health Canada (formerly the Department of National Health and Welfare). The recommendations were formally adopted by the Canadian Dental Association in April 1993.

Provider compliance with recommended dietary fluoride supplement protocol

Proper dosage of dietary fluoride supplements is important for children without access to optimally fluoridated water to balance dental caries prevention and risks of dental fluorosis. Subsequent to water fluoride assay, compliance by physicians and dentists with the recommended dietary fluoride supplement dosage schedule was determined for 446 children. Approximately one third of child patients and 42% of siblings did not receive the recommended supplement dosage.

Changes in dental caries experience of 12-year olds in low fluoride urban and rural areas of Tanzania

This report is a 2-year follow-up of a baseline study conducted in Tanzania in 1984. 377 and 448 twelve-year old primary school children were examined in Dar es Salaam (urban) and rural areas respectively. The same criteria and examiners were employed to replicate conditions in 1984 as closely as possible. The mean DMFT score has remained stable over the 2-year period in both the urban (1984: 0.67 (s.d. 1.20); 1986: 0.64 (s.d. 1.32) and rural (1984: 0.51 (s.d. 1.07); 1986: 0.40 (s.d 0.93) areas. However, a significant decrease in the mean DMFS score in Dar es Salaam from 1.19 (s.d. 2.71) in 1984 to 0.81 (s.d. 1.96) in 1986, and in rural areas from 0.78 (s.d. 1.98) in 1984 to 0.48 (s.d. 1.44) in 1986 was observed. In 1986 significantly fewer children with caries had more than 5 involved surfaces in both urban and rural areas than in 1984. In the two areas the difference in caries prevalence observed between 1984 and 1986 affected different surfaces types to varying extents. The results do not support the finding that caries is increasing in all developing countries.

Caries prevalence in the deciduous dentition of a Tanzanian urban and rural child population in relation to levels of fluoride in drinking water in 1984, 1986 and 1988

A mixed-longitudinal study to determine the prevalence of caries in the deciduous dentition of a Tanzanian child population was carried out in Morogoro Region between 1984 and 1988. Since 1978 shallow wells have been constructed in the study areas which contained water in the range of the assumed optimal fluoride level in tropical countries (0.5-1.0 ppm). Three areas were distinguished, urban, rural and villages in rural areas with an average fluoride concentration of 0.5 ppm or more in all drinking water sources present. There were no fluoridated toothpaste for sale nor were organised oral health programmes implemented in the study areas. The following background parameters were studied; age, locality, socioeconomic status and sex. School children aged 7- to 9-year (= 694), 7- to 11-year (n = 652) adn 7- to 13-year (n = 555) were examined in 1984, 1986 and 1988 respectively. For all three years of investigation, children living in villages with naturally fluoridated water were found to have significantly lower mean number of dentinal lesions than those living in urban and/or rural areas. There were no restorations found. Over the three years of investigation the mean dft*-scores were low and varied between 1.67 (urban area in 1984) and 0.79 (naturally fluoridated rural areas in 1984). No SES and sex effect on the dft-condition were found. It is recommended that water samples be collected from all drinking water sources in all regions of Tanzania and to map the results of the fluoride analyses for use in prioritization setting in planning oral health services at national and regional level.