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Fluoride intake and sky-rocketing fluorosis rates

Since artificial fluoridation was first implemented in 1945, fluorosis rates in children have become pandemic

Many of the articles below are from staunch fluoride and/or fluoridation proponents; however, several clear messages emerge:

  • There has been a significant rise in dental fluorosis rates and the severity of fluorosis since fluoridation was introduced and other fluoride products captured the marketplace;
  • Children are ingesting too much fluoride from heretofore unknown sources (see fluoride.htm for graph);
  • True dental fluorosis rates and its corresponding severity is probably under-estimated in the population;
  • According to the proponents, fluoridation is responsible for about 40% of all fluorosis;
  • There is no safe level of fluoride intake below which the effects of fluoride on enamel will not be manifest;
  • Under-nourished children are at a much higher risk of developing dental fluorosis. (the very children whose parents probably won't be able to afford the sometimes expensive cosmetic repairs needed);
  • Together with the fluoride ingested with fluoridated water or supplements, high protein diets, caffeine intake (eg., pop), tea intake, residence at high altitude, certain metabolic and respiratory disorders, and some drugs and medical conditions can significantly increase a child's risk of developing dental fluorosis;
  • Recent studies show no clinically relevant differences in tooth decay rates between those children who take fluoride supplements and those who do not;
  • Dental researchers now believe that fluoride's action is predominately topical (i.e., acts on the surface of teeth, not from inside the body);
  • Fluoride proponents are now starting to question the inadequate standards of previous dental research which led to the uncritical and mostly indiscriminate use of fluoride supplements for young children. This begs an answer to the question: are scientific standards any better today when they continue to claim fluoridation imparts benefits?;
  • Fluorosed enamel is subject to increased attrition and erosion and post-eruptive damage increases with time. Severely fluorosed enamel is structurally weak;
  • Contrary to dental rhetoric, laypeople are fully capable of diagnosing the different degrees of dental fluorosis;
  • The cosmetic ramifications of dental fluorosis may have profound effects on self-conscious teenagers; and,
  • While dentistry is calling on toothpaste manufacturers to lower the fluoride content in children's toothpaste, it's unclear whether they are actually doing anything about it.
  • The latest toothpaste advisory by fluoride proponents is at paste.htm (April, 1999)

For a definition of dental fluorosis go to definit.htm. For a conversation between a fluoridation proponent and an opponent, see lee-jr.htm.

Aoba T, The effect of fluoride on apatite structure and growth, Crit Rev Oral Biol Med, 1997;8(2):136-153.

Fluoride participates in many aspects of calcium phosphate formation in vivo and has enormous effects on the process and on the nature and properties of formed mineral. The most well-documented effect of fluoride is that this ion substitutes for a column hydroxyl in the apatite structure, giving rise to a reduction of crystal volume and a concomitant increase in structural stability. In the process of enamel mineralization during amelogenesis (a unique model for the cell-mediated formation of well-crystallized carbonatoapatite), free fluoride ions in the fluid phase are supposed to accelerate the hydrolysis of acidic precursor(s) and increase the driving force for the growth of apatitic mineral. Once fluoride is incorporated into the enamel mineral, the ion likely affects the subsequent mineralization process by reducing the solubility of the mineral and thereby modulating the ionic composition in the fluid surrounding the mineral, and enhancing the matrix protein-mineral interaction. But excess fluoride leads to anomalous enamel formation by retarding tissue maturation. It is worth noting that enameloid/enamel minerals found in vertebrate teeth have a wide range of CO3 and fluoride substitutions. In the evolutionary process from elasmobranch through enameloid to mammalian enamel, the biosystems appear to develop regulatory functions for limiting the fluoridation of the formed mineral, but this development is accompanied by an increase of carbonate substitution or defects in the mineral. In research on the cariostatic effect of fluoride, considerable emphasis is placed on the roles of free fluoride ions (i.e., preventing the dissolution and accelerating the kinetics of remineralization) in the oral fluid bathing tooth mineral. Fluoride also has been used for the treatment of osteoporosis, but much still remains to be learned about maximizing the benefit and minimizing the risk of fluoride when used as a public health measure.

Awad MA, Hargreaves JA, Thompson GW, Dental Caries and Fluorosis in 7-9 and 11-14 Year Old Children Who Received Fluoride Supplements from Birth, J. Canadian Dental Association, 1991, 60:4, 318-322.

One hundred and sixty children who had lived from birth in a region with low fluoride levels in the drinking water, and who had been offered sodium fluoride supplementation in the form of drops for daily use, were examined to evaluated dental caries and dental fluorosis. Two age ranges were selected: 7-9 years and 11-14 years. In addition to the dental examinations, questionnaires were mailed to the parents, followed-up by telephone interviews, to gather information on compliance with the fluoride supplementation program. The results showed no statistically significant differences in dental caries activity between the regular and irregular users of fluoride supplementation. Considerable dental fluorosis was found in both regular and irregular user groups of the fluoride supplement (38 to 63 per cent of the children seen), however, with no statistical difference between the user groups. Most of the fluorosis detected was of a mild degree. Fluoride supplementation under the daily control of a parent or child is not recommended because of the difficulty in maintaining regular compliance and the risk of fluorosis. [emphasis added]

Baelum V, Manji F, Fejerskov O, Posteruptive tooth age and severity of dental fluorosis in Kenya, Scand J Dental Res, 1986 Oct, 94:5, 405-410

The purpose of the present study was to assess whether the degree of severity of enamel changes in a population exhibiting rather severe dental fluorosis may be related to posteruptive tooth age and to describe the clinical manifestations of the enamel destructions. All permanent teeth in 102 children aged 10-15 yr who were born and reared in a 2 ppm fluoride area of Kenya were examined for dental fluorosis using the TF-index. Clinically, at time of eruption all teeth appeared chalky white, but already prior to coming into occlusion discrete pits had formed. A variety of more extensive damages to the surface enamel was found in teeth already in occlusion. In particular, the maxillary incisors exhibited extensive artificial attrition for cosmetic reasons, which make these teeth unreliable for accurate scoring of severity in the present population. An analysis of the proportion of teeth exhibiting TFI-scores 4+, 5+ and 6+ showed that children aged 13-15 yr had a significantly greater proportion of teeth with TFI-scores greater than or equal to 6 compared to children aged 10-12 yr (Wilcoxon, P less than 0.0001). This finding is unlikely to be a result of different fluoride exposures in the two age groups and indicates that even several years after eruption there is a trend towards an increasing severity of enamel surface destructions in children exhibiting pronounced degrees of subsurface enamel hypomineralization at time of eruption.[emphasis added]

editor's note: severe dental fluorosis is increasing in "optimally" fluoridated areas

Burt BA, The Case for Eliminating The Use of Dietary Fluoride Supplements Among Young Children, Fluoride, 1994 April, 27(2), 121. Abstract presented at the Dietary Fluoride Supplement Conference, ADA Chicago, Jan 31-Feb 1, 1994.

Fluoride supplements have been used for years to prevent dental caries, but there are three reasons why their use is inappropriate today among young children in the United States. They are (a) the evidence for the efficacy of fluoride supplements in caries prevention is not strong, (b) supplements are a clear risk for dental fluorosis, and (c) fluoride's pre-eruptive effects in caries prevention are weak. There are many studies published on the caries-preventive efficacy of supplements, but few meet the standards for acceptable clinical trials. Well-conducted studies showing supplements to be efficacious have been conducted with school-age children in supervised programs, with chewable tablets or lozenges for slow dissolution to achieve topical effects. The evidence to show that supplements are a risk factor for enamel fluorosis is strong, and so is the evidence to show that fluoride prevents caries principally through post-eruptive effects. North American children are today exposed to fluoride from many sources: drinking water, toothpaste, gels, rinses, and a considerable amount in foods and beverages. The additional cariostatic benefits that would accrue from supplement use is marginal at best, while the risk of fluorosis is strong. There is evidence that the public is more aware of the milder forms of fluorosis than was previously thought, so dental policies should be aimed at reducing fluorosis. The risks of using fluoride supplements in young children outweigh the benefits. Since there are alternative forms of fluoride to use in high-risk individuals, fluoride supplements should no longer be used for young children in North America. [emphasis added]

Chan JT, Yip TT, Jeske AH, The role of caffeinated beverages in dental fluorosis, Med- Hypotheses, 1990 Sep, 33:1, 21-22

Recent studies have demonstrated that the incidence of dental fluorosis has increased during the past decade. Greater availability and use of fluoride-containing gels, mouth rinses, dentifrices, etc., improper prescribing of fluoride supplements and ingestion of fluoride dentifrice by some children are some of the suggested determinants of dental fluorosis. However, based on the increase in consumption of tea, coffee, and other caffeine-containing beverages by the children, and the suggested determinants of dental fluorosis. However, based on the increase in consumption of tea, coffee, and other caffeine-containing beverages by the children, and the augmentative effect of caffeine on fluoride bioavailability, we theorize that the rise in incidence of dental fluorosis in North America is mainly due to the replacement of water intake by caffeine-containing beverages among the young population.

editor's note: mouth rinses and gels are not a significant factor as they are not recommended for young children under six and only 16% of eligible children take supplements, so that leaves dentifrice and fluoridation. Most pops today are made in fluoridated areas and contain caffeine

Chen YC, Lin MQ, Xia YD, Gan WM, Min D, Chen C, Nutrition Survey In Dental Fluorosis-Afflicted Areas, Fluoride, 1997 May, 30:2, 77-80

The fluoride (F) intake, diet, and health status of children in two dental fluorosis-afflicted areas in the Province of Jiangxi, China were studied in an attempt to correlate nutritional status with dental fluorosis. The relationship between mild consumption and the incidence of dental fluorosis among children was stressed in this study. Average body weight of the children approximated that of the national standard. Protein intake was above the national standard of 0.75 g/kg body weight/day, But the protein was derived mainly from plant sources. Calcium intake was found to be insufficient. Based on the diet and fluoride intake of the studied groups, the areas with a better nutritional status were found to have a lower incidence of dental fluorosis. The incidence among milk-consuming children was lower than that of non-milk consuming children.

editor's note: tragically, the very people dentistry claims will benefit from ingesting fluoride -- poor children -- are the ones who are most affected by fluoride's toxic effects because of inadequate nutrition. This is a universal truth whether in the U.S. A., Canada or in countries where dental and/or skeletal fluorosis is endemic

Chlebna-Sokól D, Czerwinski E, Bone Structure Assessment On Radiographs Of Distal Radial Metaphysis In Children With Dental Fluorosis, Fluoride, 1993 Jan, 26:1, 37-44

Clark C, Trends in prevalence of dental fluorosis in North America, Community Den Oral Epidem, 1994, 22, 148-52

This review of the literature was undertaken to demonstrate the changing trends in the prevalence of dental fluorosis in North America. Using Dean's early work to establish a baseline for the prevalence of dental fluorosis, results of more recent prevalence surveys were used to establish a range for the occurrence of dental fluorosis today. These results suggest that the prevalence of dental fluorosis now ranges somewhere between 35% and 60% in fluoridated communities and between 20% and 45% in nonfluoridated areas, depending on the influence of difference local conditions. While the increase has occurred primarily in the very mild and mild categories of dental fluorosis, there is also some evidence that the prevalence is increasing in the moderate and severe classifications as well.

Fejerskov O, Larsen MJ, A Richards and V Baelum, Dental tissue effects of fluoride, Fluoride, 1994 October, 27(4), 236, from Advances in Dental Research, 1994, 8(l), 15-31.

It is now well-established that a linear relationship exists between fluoride dose and enamel fluorosis in human populations. With increasing severity, the subsurface enamel all along the tooth becomes increasingly porous (hypomineralized), and the lesion extends toward the inner enamel. In dentin, hypomineralization results in an enhancement of the incremental lines. After eruption, the more severe forms are subject to extensive mechanical breakdown of the surface. The continuum of fluoride-induced changes can best be classified by the TF index, which reflects, on an ordinal scale, the histopathological features and increases in enamel fluoride concentrations. Human and animal studies have shown that it is possible to develop dental fluorosis by exposure during enamel maturation alone. It is less apparent whether an effect of fluoride on the stage of enamel matrix secretion, alone, is able to produce changes in enamel similar to those described as dental fluorosis in man. The clinical concept of post-eruptive maturation of erupting sound human enamel, resulting in fluoride uptake, most likely reflects subclinical caries. Incorporation of fluoride into enamel is principally possible only as a result of concomitant enamel dissolution (caries lesion development). At higher fluoride concentrations, calcium-fluoride-like material may form, although the formation, identification, and dissolution of this compound are far from resolved. It is concluded that dental fluorosis is a sensitive way of recording past fluoride exposure because, so far, no other agent or condition in man is known to create changes within the dentition similar to those induced by fluoride. Since the predominant cariostatic effect of fluoride is not due to its uptake by the enamel during tooth development, it is possible to obtain extensive caries reductions without a concomitant risk of dental fluorosis. [emphasis added]

editor's note: in other words, ingesting fluoride (fluoridated water or supplements) is unnecessary.

Fejerskov O, Manji F, Baelum V, The Nature and Mechanisms of Dental Fluorosis in Man, Journal Dental Research, 1990 February, 69 (Special Issue):692-700.

Any use of fluorides, whether systemic or topical, in caries prevention and treatment in children results in ingestion and absorption of fluoride into the blood circulation. The remineralization of teeth under formation may be affected so that dental fluorosis may occur. Dental fluorosis reflects an increasing porosity of the surface and subsurface enamel, causing the enamel to appear opaque. The clinical features represent a continuum of changes ranging from fine white opaque lines running across the tooth on all parts of the enamel to entirely chalky white teeth. In the latter cases, the enamel may be so porous (or hypomineralized) that the outer enamel breaks apart posteruptively and the exposed porous subsurface enamel becomes discolored. These changes can be classified clinically by the TF index to reflect, in an ordinal scale, the histopathological changes associated with dental fluorosis. Compared with Dean's and the TSIF index, we consider the TF index to be more precise. Recent studies on human enamel representing the entire spectrum of dental fluorosis have demonstrated a clear association between increasing TF score and increasing fluoride content of the enamel. So far, no useful data on dose (expressed in mg fluoride/kg b.w.) -- response (dental fluorosis) relationships are available. In this paper, we have, therefore, re-evaluated the original data by Dean et at (1941, 1942), Richards et al. (1967), and Butler et al. (1985) from the (USA, by applying the equation of Galagan and Vermillion (1957) which permits the calculation of water intake as a function of temperature. By so doing, it can be demonstrated that there is a linear association between fluoride dose and dental fluorosis (r2 = 0.87). Even with very low fluoride intake from water, a certain level of dental fluorosis will be found in a population. When the linear dose-response curve is applied to previous data from the use of fluoride supplements, these data are in full accordance. This indicates that we already have useful data available which to some extent allows us to predict prevalence and severity of fluorosis in a child population which is exposed to a known amount of fluoride. Because dental fluorosis may occur in some individuals and populations to a higher prevalence and degree than expected and there exist rare cases who exhibit clinical changes similar to those of fluorosis--but with no known excessive fluoride background--it is concluded that it is important to intensify studies on factors which alone or in combination can make individuals more or less susceptible to the effect of fluoride.

Giambro NJ, Prostak K, Denbesten PK, Characterization Of Fluorosed Human Enamel By Color Reflectance, Ultrastructure, And Elemental Composition, Fluoride, 1995 November, 28:4, 216, from Caries Research 29 (4) 251-257 1995.

Mature fluorosed human enamel has been described as a subsurface: enamel hypomineralization, with porosity increasing relative to the degree of fluorosis. The purpose of the current study was to quantitatively measure the color of the fluorosed enamel by light reflectance, and to further characterize the enamel by scanning electron microscopy. Teeth with varying degrees of fluorosis were obtained and divided in groups of mild, moderate and severe fluorosis using Dean's Index for fluorosis. The color of the labial enamel surface was measured using a Minolta Chroma Meter CR241 (Minolta, Ramsey, N.J., USA). The teeth were further characterized for elemental composition using an energy-dispersive spectrometer, and imaged in both secondary and backscattered electron modes. The results of this study showed that the moderately and severely fluorosed enamel contained an uneven distribution of areas which were more electron-absorbent with a relative\ increased carbon content. The changes in the physical characteristics of the teeth could be quantitated by measurements of light reflectance. The color of the teeth was significantly different between groups, with all groups significantly different than normal.

Gotjamanos T, Safety issues related to the use of silver fluoride in paediatric dentistry. Aust Dent J, 1997 Jun, 42(3), 166-168.

Due to its exceedingly high fluoride content, 40% silver fluoride solution has the potential to cause fluorosis when used in young children. In vitro testing conducted in the present investigation indicates that application of 40% silver fluoride to deep carious lesions or its use as a 'spot' application agent could result in 3 to 4 mg of fluoride reaching the systemic circulation. As scientifically-based clinical trials on the safety of 40% silver fluoride have not been conducted, it would be appropriate for it to be withdrawn from further clinical use until proper testing and evaluation have been carried out. In view of the possibility that lower strength solutions of silver fluoride (1-4%) may be just as effective as 40% in 'arresting' deep caries, testing should focus on such solutions, particularly as the potential for toxicity from their fluoride content would be reduced by a factor of 10-40.

editor's note: clearly, regulatory agencies and dental associations have failed our children if they allow untested products into the marketplace

Hawley GM, Ellwood RP, Davies RM, Dental caries, fluorosis and the cosmetic implications of different TF scores in 14-year-old adolescents, Community Dent Health, 1996 Dec, 13(4), 189-192.

The aims of this study were to determine the opinions of a group of adolescents about the cosmetic acceptability of a range of fluorosis, investigate the prevalence and severity of fluorosis in the sample and consider the extent to which fluorosis levels were related to their dental caries experience. A random sample of 534 14-year-old pupils from the non-fluoridated industrial city of Manchester were examined for caries and fluorosis. Each subject then examined six photographs of upper anterior teeth showing a range of TF scores 0-4 and were asked to rate the appearance of each as either very poor, poor, acceptable, good or very good and to indicate whether they would request treatment if their teeth were so affected. Four hundred and seventy-six subjects (89 per cent) had TF scores of 0. Of the 58 subjects (11 per cent) with fluorosis, 27 (5 per cent) scored TF = 1; 22 (4 per cent) TF = 2; 7 (1 per cent) TF = 3 and one subject scored TF = 4. The subjects who had no fluorosis had a mean DMFT of 3.0 which was significantly higher than the mean of 2.2 among those with any fluorosis. The proportion of subjects who rated the photographs as poor or very poor fell from 29 per cent for TF score 0 to 15 per cent for TF score 2 and then increased to 92 per cent for TF score 3. The responses of the subjects regarding their desire for treatment matched closely with their opinions on appearance; the majority of subjects expressed concern over the appearance of teeth with TF scores of 3 and higher. It is concluded that the prevalence of aesthetically objectionable dental fluorosis was low and that mild fluorosis was associated with a lower risk of dental caries and a more acceptable appearance. It is essential that a balanced view of the relative benefits and risks of the use of fluorides is maintained and proven benefits are not overwhelmed by largely unfounded aesthetic concerns.

editor's note: Comments of "significantly" lower caries levels in fluorosed teeth are meaningless here given the paltry number of children with fluorosis - 58. See related article: Riordan PJ, Perceptions of Dental Fluorosis for contrasting opinion on "unfounded aesthetic concerns."

Heilman JR, Kiritsy MC, Levy SM, Wefel JS, Fluoride concentrations of infant foods, J Am Dent Assoc, 1997 Jul, 128(7), 857-863.

Infants who ingest high amounts of fluoride can be at risk of dental fluorosis. The authors analyzed the fluoride concentration of 238 commercially available infant foods. Fluoride concentrations ranged from 0.01 to 8.38 micrograms of fluoride per gram, with the highest fluoride concentrations found in infant foods containing chicken. Infant foods, especially those containing chicken, should be considered when determining total fluoride intake.

Heller KE, Eklund SA, and Burt BA, Dental caries and dental fluorosis at varying water fluoride concentrations, Journal of Public Health Dentistry 57 (3) 136-143 1997

Objectives: The purpose of this study was to investigate the relationships between caries experience and dental fluorosis at different fluoride concentrations in drinking water. The impact of other fluoride products also was assessed.

Methods: This study used data from the 1986-87 National Survey of US School-children. Fluoride levels of school water were used as an indicator of the children's water fluoride exposure. The use of fluoride drops, tablets, professional fluoride treatments, and school fluoride rinses were ascertained from caregiver questionnaires. Only children with a single continuous residence (n = 18,755) were included in this analysis.

Results: The sharpest declines in dfs and DMFS were associated with increases in water fluoride levels between 0 and 0.7 ppm F, with little additional decline between 0.7 and 1.2 ppm F. Fluorosis prevalence was 13.5 percent, 21.7 percent, 29.9 percent, and 41.4 percent for children who consumed <0.3, 0.3 to <0.7, 0.7 to 1.2, and >1.2 ppm F water. In addition to fluoridated water, the use of fluoride supplements was associated with both fewer caries and increased fluorosis.

Conclusions: A suitable trade-off between caries and fluorosis appears to occur around 0.7 ppm F. Data from this study suggest that a reconsideration of the policies concerning the most appropriate concentrations for water fluoridation might be appropriate for the United States.

Key words: Caries prevention, Dental caries, Dental fluorosis, Water fluoridation. Reprints: K E Heller, University of Michigan, School of Public Health, Program of Dental Public Health, Ann Arbor, MI 48109, USA.

Horowitz HS, The need for toothpastes with lower than conventional fluoride concentrations for preschool-aged children, J Public Health Dent, 1992, 52(4), 216-221.

Since 1945, when community water fluoridation was first implemented in the United States, not only has the procedure grown to cover more than half of the US population, but the development and use of other fluoride methods have expanded greatly. A concomitant, dramatic decrease has occurred in the caries prevalence of US school-aged children. Recent studies indicate, however, that the prevalence and, to a lesser extent, the intensity of dental fluorosis have increased in schoolchildren in both fluoridated and fluoride-deficient areas. Several studies show that young children inadvertently ingest sizable proportions of toothpaste during toothbrushing. Although ingestion of fluoride toothpastes by preschool-aged children may not be the major contributor to the increase in fluorosis, the findings of at least four studies suggest that the use of fluoride toothpastes by young children is a risk factor. The direct dose-response relation between effectiveness and fluoride concentration of toothpastes is far from clear-cut and, at best, is weak. Thus, considering today's reduced risk of caries, it is timely to market fluoride toothpastes in the US with 400-500 ppm fluoride for preschool-aged children, who are still at risk for developing fluorosis, as has been done in several other countries. Dental public health authorities must work with toothpaste manufacturers, professional organizations, and regulatory agencies to facilitate the approval and marketing of such pediatric fluoride toothpastes.

Ismail AI, Fluoride supplements: current effectiveness, side effects, and recommendations, Community Dental Oral Epidemiology, 1994, 22, 164-72

A critical review of the literature was conducted to determine the current effectiveness of fluoride supplements in caries prevention and their role as risk factors for dental fluorosis. Use of fluoride supplements by young children is idiosyncratic and all of the studies which investigated the effectiveness of this regimen suffered from a significant drop in the number of participants receiving daily supplements. The scientific evidence supports the efficacy of fluoride supplements in caries prevention but there is weaker support for their effectiveness. Fluoride supplements are a risk factor for dental fluorosis, though their contribution to the increase in fluorosis prevalence is less than that of water fluoridation and fluoridated dentifrices because of their more limited and shorter use. There is also evidence that fluoride supplements are used inappropriately in fluoridated areas. The availability of optimal levels of fluorides in beverages in non-fluoridated communities raises the question of whether fluoride supplements are needed in the 1990s, and whether it is time to consider the total fluoride intake not only from water but also from foods, beverages, and dentifrices when recommending supplements. A re-evaluation of the need for and dosage schedules of fluoride supplements is warranted.

Kiritsy MC, Levy SM, Warren JJ, Guha-Chowdhury N, Heilman JR, Marshall T, Assessing fluoride concentrations of juices and juice-flavored drinks, JADA, 1996 Jul, 127 (7), 895-902

Few studies have investigated fluoride exposures from juices and juice-flavored drinks manufactured with water. In this study, the authors analyzed 532 juices and juice drinks for fluoride. Fluoride ion concentrations ranged from 0.02 to 2.80 parts per million, in part because of variations in fluoride concentrations of water used in production. Children's ingestion of fluoride from juices and juice-flavored drinks can be substantial and a factor in the development of fluorosis.

Krook L, et al., Dental fluorosis in cattle, Cornell-Vet, 1983 Oct., 73:4, 340-362

Levine RS, Beal JF, Fleming CM, A photographically recorded assessment of enamel hypoplasia in fluoridated and non-fluoridated areas in England. British Dental Journal, 1989 Apr 8, 166(7):249-52. [note fluorosis is sometimes referred to as enamel hypoplasia]

This study assesses the effect on enamel formation of the use of fluoride toothpaste in a fluoridated area. The prevalence of enamel hypoplasia in 251 9-10-year-old children born and raised in a fluoridated city (Birmingham) was compared with that in 319 similar children born and raised in a non-fluoridated city (Leeds). Observer bias was eliminated by the use of a new photographic technique, enabling colour slides of both groups to be assessed together in a random order. Scoring was done using both the Jackson-Al-Alousi (J-A) index, which is designed to record nonspecific hypoplasias and the Tooth Surface Index of Fluorosis (TSIF). Both were compared to the results from conventional clinical recording using the J-A index. The results showed that the photographic method was highly reproducible and more sensitive than conventional recording and showed a higher level of mild fluorosis in the fluoridated area. However, no evidence of an increase in the higher grades of fluorosis was found. It is concluded that the use of fluoride toothpaste by young children in fluoridated areas is unlikely to produce aesthetically unacceptable levels of enamel fluorosis. [emphasis added]

editor's note: one of the reasons some dentists claim not to see increasing levels of fluorosis in their practice is because the entire spectrum of fluorosis damage is more visible on photographs. The small overhead light dentists use is not full-spectrum lighting. It doesn't work as well as natural light for determining the severity and incidence of fluorosis because the color changes and striations (lines of demarcation) in the teeth are often washed out. See related article: Nunn JH, et al., Assessment of enamel opacities in children in Sri Lanka and England using a photographic method. More on this important point to come with W.H.O. guidelines regarding lighting in dental surveys recording fluorosis levels].

Levy SM, Kiritsy MC, Slager SL, Warren JJ, Kohout FJ, Patterns of fluoride dentifrice use among infants, Pediatr Dent, 1997 Jan 19 (1) 50-55.

The early use of fluoride dentifrice and use of larger quantities recently have been identified as risk factors for dental fluorosis. However, little is known about fluoride dentifrice use and ingestion among infants and young children whose developing permanent teeth are at risk for dental fluorosis. This paper reports on patterns of fluoride dentifrice use among a birth cohort up to 12 months of age as reported by mothers by written questionnaire. Among those with teeth, percentages whose teeth were brushed at age 6, 9, and 12 months were 12.9%, 36.7%, and 64.5%, respectively. Percentages brushing with fluoride dentifrice were 1.9%, 11.7%, and 31.7%. Among those using dentifrice, the percentages using fluoride dentifrice were 94-97%. Among those using dentifrice, mean estimated quantities of fluoride from dentifrice used per brushing were 0.11, 0.14, and 0.17 mg F (range up to 0.88 mg). Among users, mean quantities of fluoride from dentifrice used per day were 0.21, 0.20, and 0.19 mg F (range up to 1.75 mg). Results suggest that fluoride dentifrice use among infants varies greatly, can be substantial, and can be a risk factor for dental fluorosis.

Levy SM, Kohout FJ, Guhachowdhury N, Kiritsy MC, Heilman JR and Wefel JS, Infants' Fluoride Intake From Drinking Water Alone, And From Water Added To Formula, Beverages, And Food, Fluoride, 1996 Feb, 29:1, 54, from J. of Den. Res., 1995, 74:7, 1399-1407.

In infants, the majority of total ingested fluoride is obtained from water, formula and beverages prepared with water, baby foods, and dietary fluoride supplements. Few studies have investigated the distribution of fluoride intake from these sources among young children at risk for dental fluorosis. The purpose of this study was to assess estimated water fluoride intake from different sources of water among a birth cohort studied longitudinally from birth until age 9 months. Parental reports were collected at 6 weeks, 3 months, 6 months, and 9 months of age for water, formula, beverage, and other dietary intake during the preceding week. Fluoride levels of home and child-care tap and bottled water sources were determined. This report estimates daily quantities of fluoride ingested only from water-both by itself and used to reconstitute formula, beverages, and food. Daily fluoride intake from water by itself ranged to 0.43 mg, with mean intakes i 0.05 mg. Water fluoride intake from reconstitution of concentrated infant formula ranged to 1.57 mg, with mean intakes by age from 0. 18 to 0.31 mg. Fluoride intake from water added to juices and other beverages ranged to 0.67 mg, with means < 0.05 mg. Estimated total daily water fluoride intake ranged to 1.73 mg fluoride, with means from 0.29 to 0.38 mg.

Levy SM, Kohout FJ, Kiritsy MC, Heilman MR, Wefel JS, Infants Fluoride Ingestion From Water, Supplements and Dentifrice, Fluoride, 1996 May, 29:2,113. from JADA, 1995, 126:12 1625-1632.

Concerns about dental fluorosis and the paucity of detailed fluoride intake data prompted this longitudinal study of fluoride intake in infants from birth to 9 months of age. On average, water fluoride intake greatly exceeded that from dietary fluoride supplements or fluoride dentifrice. However, fluoride supplements and dentifrice contributed substantial proportions of fluoride intake among children using them. Some children had estimated fluoride intake from water, supplements and dentifrice that exceeded the recommended "optimal" intake (a level that has yet to be determined scientifically). Practitioners should estimate fluoride ingestion from all these sources if considering systemic fluoride supplementation. [emphasis added]

Levy SM, Kiritsy MC, Warren JJ, Sources Of Fluoride Intake In Children, Fluoride, 28:4, 1995 November, 215-216, from J. of Public Health Dentistry, 55 (1), 39-52 1995.

Wide variations in fluoride intake among children make estimating fluoride intake difficult. This paper discusses the various sources of fluoride intake among children, beginning with a review of the fluoride concentrations of water and other beverages, foods, and therapeutic fluoride products. A review of previous studies' estimates of fluoride intake from diet, dentifrice, fluoride supplements. fluoride mouthrinses, and gels, as well as total fluoride intake also is presented. Then, estimates of fluoride intake among young children of different age groups are summarized and examples demonstrating the high level of variability of fluoride intake, both from individual sources and in total, are presented. Lastly, this paper discusses the implications of our current level of knowledge of children's fluoride intake, and presents recommendations for the use of fluoride for children in light of this current knowledge. The major recommendations are that: (1) the fluoride content of foods and beverages, particularly infant formulas and water used in their reconstitution, should continue to be monitored closely in an effort to limit excessive fluoride intake; (2) ingestion of fluoride from dentifrice by young children should be controlled, and the use of only small quantities of dentifrice by young children should be emphasized; and (3) dietary fluoride supplements should be considered a targeted preventive regimen only for those children at higher risk for dental caries and with low levels of ingested fluoride from other sources.

Lewis DW, Banting DW, Water fluoridation: current effectiveness and dental fluorosis. Community Dental Oral Epidemiology, 1994, 22, 53-8.

This paper reviewed the literature on the evidence for water fluoridation's effectiveness under current conditions of multiple fluoride use at recommended and at reduced concentrations, the extent of dental fluorosis at different fluoride concentrations, and the "halo" effect of water fluoridation. Using the relative difference in dental caries between communities with low and optimal water fluoride as an indicator, the effectiveness of water fluoridation has decreased over time as the use of other fluorides has increased. Thus the effectiveness of water fluoridation alone cannot now be determined. Compared to the early fluoridation studies, the differences in dental caries and fluorosis prevalence between fluoridated and non-fluoridated areas have markedly narrowed. Both the prevalence and severity of dental fluorosis have increased since 1945: however. the portion of fluorosis due to water fluoridation is now less (40%) than that attributed to other fluoride sources (60%). Research also suggests that the "halo" effect of community water fluoridation may result in a significantly greater intake of fluoride for people in non-fluoridated communities. This review recognized that since water fluoridation has unique advantages from the perspectives of distribution, equity, compliance and cost-effectiveness over other fluoride technologies, it remains as the fundamental base for caries prevention. The increasingly greater contribution that other sources of fluoride make to dental fluorosis suggests that these sources of fluoride, many of which are used on an elective basis, should be more closely examined for needed changes.

Liefde B de, Longitudinal survey of enamel defects in a cohort of New Zealand Children, Comm Dent Oral Epidem, 1988, 16, 218-221.

Nunn JH, Ekanayake L, Rugg-Gunn AJ, Saparamadu KD, Assessment of enamel opacities in children in Sri Lanka and England using a photographic method, Community Dent Health, 1993 Jun, 10:2, 175-188.

Colour photographs were taken of the labial surface of both maxillary central incisor teeth of children aged 12 years, living in Sri Lanka and England. In each country, children were included who lived in communities receiving drinking water containing 0.1, 0.5 and 1.0 ppm F, and within these communities children were classed as high or low socio-economic (SE) status. The photographs were examined 'blind' by two examiners independently. These pertained to 670 children, 332 in Sri Lanka and 338 in England. The index of Developmental Defects of Enamel (DDE) was used, as modified by Clarkson and O'Mullane (1989), to measure type and extent of opacity. Intra- and inter-examiner agreement was substantial. Prevalence of opacities ranged from about a quarter of teeth in the 0.1 ppm F area in Sri Lanka to over 60 per cent of teeth in the high socio-economic group in the 1.0 ppm F area in England. Higher prevalences of opacities were recorded in: (1) the high SE group than the low SE group in the 1.0 ppm F area in England, (2) the 1.0 ppm F area than in the 0.1 ppm F area in both countries, (3) in Sri Lanka than in England in low SE groups in the 1.0 ppm F areas. The greatest differences occurred in diffuse opacities. When these data were compared with results of clinical examinations of these same tooth-surfaces by one examiner (n = 506) more teeth were graded 'normal' clinically and more teeth graded as having opacities photographically. Both demarcated and diffuse opacities were scored more frequently from photographs than clinically in both countries [emhasis added].

editor's note: fluorosis is sometimes referred to as enamel opacities, but this is not the correct terminology. See related article: Levine RS, et al., A photographically recorded assessment of enamel

Riordan PJ, The Place Of Fluoride Supplements In Caries Prevention Today, Fluoride, 1997 Feb, 30:1, 67, from Australian Dent J, 1996, 41:5, 335-342.

There are very few scientifically good clinical trials of fluoride supplements, and those that can be considered methodologically adequate suggest that the contribution of fluoride supplements to caries prevention is slight. This may be partly a consequence of the fact that fluoride is much more widely available today than was the case a generation ago when fluoride toothpaste was not widely used and water fluoridation was not fully implemented. Although some families are conscientious in their use, compliance with fluoride supplement recommendations is generally poor over longer periods, making them a poor public health measure. There is substantial evidence that supplements cause dental fluorosis when used in accordance with recommendations for infants and small children. If the public becomes concerned about dental fluorosis as an aesthetic problem, all fluoride use may be put at risk. Supplements should no longer be recommended for caries prevention in children in areas with little fluoride in water but may be useful for persons with intractable caries risks. If supplements are recommended for children, a more cautious dosage schedule should be used. The fact that supplements have been recommended uncritically for many years on the basis of inadequate research raises questions about the standards of dental science.[emphasis added]

Riordan PJ, Dental Fluorosis, Dental Caries And Fluoride Exposure Among 7-year-olds, Fluoride, 1993 July, 26:3, 231-232, from Caries Research, 1993, 27, 71-77.

Mild dental fluorosis is frequently linked to fluoridated water, but discretionary fluoride sources may also be important. The aim of this study was to record age of weaning and fluoride exposure from water, toothpaste and supplements, and to relate these to the presence of caries and fluorosis in children born in 1983. In Perth (Western Australia) 14 school classes were selected. The 350 children (mean age 7.5 years) ultimately included gave fluoride exposure data for the period birth to 4 years of age. Caries (DMFT, WHO criteria, no radiographs) and dental fluorosis (TF index, dry permanent incisors) were registered clinically. Most (89%) children had lived at least 2.5 years in a fluoridated area. Supplement use was minimal and unrelated to caries or fluorosis. Mean age of weaning of those who had been breastfed was 7.7 months; by 9 months, 74% had been weaned. Eighty-five percent liked toothpaste, 60.7% had swallowed it, and the mean age of starting to use it was 1.5 (SD 0.96) years. Caries prevalence was 0.1 and mean DMFT was 0.13. The prevalence of fluorosis was 0.48; 63% of fluorosis was TF score 1. Residence in a fluoridated area for greater-than-or-equal-to 2.5 of the first 4 years of life had an odds ratio (OR) of 4.9 for fluorosis. Weaning before 9 months of age, swallowing toothpaste and liking toothpaste were also statistically significant risk factors. Major risk factors for more severe fluorosis (TF greater-than-or-equal-to 2) were early weaning and swallowing toothpaste (ORs 2.77 and 2.64, respectively). Residence in a fluoridated area (OR 2.2) was not a statistically significant risk factor. These findings confirm a high prevalence of mild fluorosis among children who have been exposed to fluoride in their earliest years. High attributable proportions associated with age of weaning and toothpaste use suggest that elimination of fluoride from formula and a reduced fluoride concentration in toothpaste would contribute significantly to reducing the prevalence of more visible fluorosis.

Riordan PJ, Perceptions of Dental Fluorosis, Fluoride, January 1994, 27:1, 54-55, abstracted from Journal of Dental Research, 72 (9), 1268-1274 1993.

Mild dental fluorosis has long been accepted as a side-effect of water fluoridation and, more recently, has been recognized as a consequence of the use of other fluoride-based caries-preventive strategies. Traditionally, dental health professionals have not seen this as being of public health importance, but members of the public have not been asked their opinion. The purpose of the present study was to gather the opinions of lay groups concerning the appearance of the teeth of children with various degrees of fluorosis. Twenty eight children, born in 1978, who had earlier participated in a study of fluorosis in Perth (Western Australia), allowed 10 observers to look at their upper central incisors under good viewing conditions. Fluorosis in these teeth ranged from TF score 0 (no fluorosis) to TF score 3. The observers were university students, parents, public servants, or dentists. They responded to statement items about the appearance of the teeth. The results, based on just over 3000 responses, showed that lay and dental observers could distinguish between different fluorosis levels. In response to a statement that the teeth appeared pleasing, a large majority agreed when the TF score was 0, but agreement declined as the TF score increased; when the TF score was 3, most people disagreed. Similarly, observers felt that the appearance would increasingly embarrass the child as the TF score increased. Observers, except the dentists, tended to feel that higher TF scores indicated neglect on the part of the child. Most observer groups felt that fluorosis would be no greater an esthetic problem for girls than for boys, but for more severe fluorosis, the dentists saw the appearance as being a greater problem for girls. The dentists responded that most fluorosis did not require any treatment, but when the TF score was 3, a majority of them felt that esthetic treatment would be warranted. The results suggest that, for these observers, fluorosis score TF = 2 or greater was easily noticed, and when the TF score was 3, fluorosis aroused concern in most observers. Recent epidemiological studies reported TF scores of2 or more in 11.3% of 12-year-olds and 17.5% of 7-year-olds in Perth. Strategies to reduce the prevalence of fluorosis with TF score 2 and avoid fluorosis with TF score 3 - including reduction of toothpaste ingestion, removal of fluoride from infant formulae, and avoidance of inappropriate supplement use-should be devised and implemented. [emphasis added]

Riordan PJ. Guidelines for the use of dietary fluoride supplements in Australia. Australian Dental Journal, 1989 Aug, 34(4):359-62.

A survey in 1988 of brands of fluoride supplements available in a non-fluoridated town in Western Australia, and tablets described in pharmaceutical product registers, revealed that six brands of tablets and one brand of solution (drops) were on the market. Tablets contained 2.2 mg or 1.1 mg NaF; the solution contained 2.2 mg NaF per mL. All products provided age-dose schedules which would give fluoride supplementation at levels greater than the National Health and Medical Research Council guidelines. In one case, infants following the schedule would receive four times the recommended dose for the first two years of life. Compliance with several of the age-dose schedules would be certain to cause significant dental fluorosis. Whether the others caused fluorosis would depend on the quantity of fluoride in the diet, and consumption of fluoride toothpaste. The survey showed a generalized disregard on the part of the ethical pharmaceutical industry for the risk of dental fluorosis, and reveals a need for a voluntary, or legally enforced, code of conduct for manufacturers of fluoride supplements. The value of guidelines which are not monitored is doubtful.

Rock WP, Sabieha AM, The relationship between reported toothpaste usage in infancy and fluorosis of permanent incisors, Br Dent J, 1997 Sep 13, 183(5), 165-170.

OBJECTIVE: To examine a possible relationship between reported toothbrushing habits in infancy and fluorosis of permanent maxillary incisors at age 8-9 years. DESIGN: Comparison of clinical findings with retrospective survey data. SETTING: Five primary schools in the City of Birmingham where the water is fluoridated at 1.0 mg F/l. SUBJECT AND METHODS: Results of clinical examinations were compared with historical data collected via parental questionnaires. Maxillary central incisors of 325 consecutive children were examined for fluorosis clinically and photographically according to the criteria of the Modified Thylstrup and Fejerskov Index. 112 children had fluorosis and 213 did not. Information concerning toothbrushing habits in infancy was obtained via a questionnaire to parents who were also asked to add paste to a brush in a similar way to when the children were small. From a combination of questionnaire replies and paste weights the amount of fluoride that each child may have ingested from toothpaste each day was then estimated. RESULTS: Highly significant associations were found between estimated fluoride ingestion from toothpaste and fluorosis. The mean DMF score of the fluorosis group was half that of the fluorosis-free children. The prevalence of fluorosis among children in ACORN group A-C was significantly greater than in groups D-F. CONCLUSIONS: The results of the study suggest that toothpaste swallowing may be a factor in the production of fluorosis.

Rugg-Gunn AJ, al-Mohammadi SM, Butler TJ, Effects of fluoride level in drinking water, nutritional status, and socio-economic status on the prevalence of developmental defects of dental enamel in permanent teeth in Saudi 14-year-old boys, Caries Res, 1997, 31(4), 259-267.

Fourteen-year-old boys from three regions of Saudi Arabia were surveyed in 1992/3. These regions were Jeddah (which receives desalinated water containing 0.22 mgF/l), Riyadh (receiving water containing 0.78 mgF/l) and Qassim (2.66 mgF/l). For each of these urban communities an adjacent rural community was selected; these received water with 0.25, 0.80, and 2.71 mg/l, respectively. Subjects from the urban communities were classified into high, medium and low socio-economic status based on area of residence, income and education level of parents. Nutritional status was calculated from height and age using WHO methods and expressed as height for age percentage of the median of the reference population (HAM); children with HAM scores of less than 95% were classed as malnourished. The developmental defects of enamel index was recorded on the buccal surface of all permanent teeth, by one examiner. Colour photographs of anterior teeth were read 'blind' to investigate examiner bias between regions-there was no bias. A total of 1,539 children were examined who had been continuously resident in that community. Overall, 83% of subjects had one or more enamel defects with a mean number of teeth affected per person of 9.6. Diffuse defects were the most common. Multivariate analyses revealed that all three variables-region, nutritional status, socio-economic status-were statistically significantly related to the prevalence of defects and the number of teeth affected: prevalence was highest in the region with the highest water fluoride concentration, in rural areas and in malnourished subjects. Maxillary incisor teeth were the most affected teeth in all regions. The findings have implications for those in public health who determine optimum fluoride levels in drinking water in Saudi Arabia and beyond. [emphasis added]

editor's note: nutritional deficiences increase the severity and prevalence of dental fluorosis in our children. That's also why skeletal fluorosis rates are higher in poorer countries even though fluoride exposure may be similar. Nutrients such as calcium, vitamin C, magnesium, etc. offset the toxicity of fluoride.

Seow WK, Thomsett MJ, Dental fluorosis as a complication of hereditary diabetes insipidus: studies of six affected patients, Pediatr Dent, 1994 Mar, 16 (2), 128-132.

Hereditary diabetes insipidus is a rare endocrine disorder caused by a deficiency of the antidiuretic hormone, vasopressin. The disease is characterized by polyuria, extreme thirst, and polydipsia. In this study of six affected members from two families with hereditary diabetes insipidus, it was found that two children who drank water fluoridated at optimum levels developed moderate to severe fluorosis. By contrast, four other affected patients who did not consume fluoridated water showed normal dentitions. This report indicates that dental fluorosis may be an important complication of diabetes insipidus, and demonstrates the possibility that excessive consumption of optimally fluoridated water can lead to severe developmental enamel defects.

editor's note: there is evidence that fluoride can cause polydypsia -- increased thirst. Moreover, because fluid intake is increased, diabetics are at increased risk of developing skeletal fluorosis

Sergio GS, Weber A, Torres C, Fluoride content of tea and amount ingested by children, Odontol Chil, 1989 Dec, 37:2, 251-255

The fluoride concentration on their respective infusions was determined in the twelve most popular brand of tea which can be obtained in Valparaiso, Chile. Fluoride concentration was measured 5, 45, and 180 minutes after tea preparation, by using an specific fluoride electrode. The amount of ingestion of tea in children was estimated by means of a survey on 303 children from a sample of 7,690 boys and girls living in a fluoridated area. The data revealed a large variability in fluoride concentration depending on the brand of tea. Mean fluoride concentration was 2.36 mg F/l at the five first minutes. Sixty eight per cent of children drinking tea as usual beverage, therefore it was estimated that about 22.1% of this sample have risk of dental fluorosis.

editor's note: tea leaves accumulate more fluoride than any other edible plant. Case-reports have shown that arthritis can be markedly alleviated after tea-drinking is stopped

Shupe JL, Christofferson PV, Olson AE, Allred ES, Hurst RL, Relationship of cheek tooth abrasion to fluoride-induced permanent incisor lesions in lifestockAm J Vet Res, 1987 Oct, 48:10, 1498-1503

Teeth from cattle, sheep, and horses that ingested various fluoride intakes and teeth from field studies of these species plus deer, elk, and bison were examined for abnormalities. Approximately 99,000 animals in 322 herds were examined for fluorosis. From field studies, 988 cattle of various ages and with different degrees of dental fluorosis were slaughtered and necropsied. The severity of fluoride-induced mottling, hypoplasia, and abnormal abrasion of paired permanent incisor teeth was correlated with abrasion of premolar and molar (cheek) teeth that form and mineralize at approximately the same age. Severe irregular wear of cheek teeth impaired mastication and resulted in poor utilization of feed and unthriftiness. Excessive amounts of fluoride during tooth formation and mineralization induce characteristic dental changes. Offspring from the fluoride-affected animals did not have discernible fluoride-induced lesions in the deciduous teeth.

Silva M, Reynolds EC, Fluoride Content Of Infant Formulae In Australia, Fluoride, 1996 May, 29:2, 15-116, from Australian Den J., 1996, 41:1, 37-42.

The prevalence of dental fluorosis in Australia and the United States of America has increased in both optimally fluoridated and non-fluoridated areas. This has been attributed to an increase in the fluoride level of food and beverages through processing with fluoridated water, inadvertent ingestion of fluoride toothpaste, and the inappropriate use of dietary supplements. A major source of fluoride in infancy is considered to be infant formula which has been implicated as a risk factor for fluorosis in a number of studies. In this study the fluoride content of the infant formulae commonly used in Australia was determined. The acid diffusible fluoride of each powdered formula was isolated by microdiffusion and measured using a fluoride ion-specific electrode. The fluoride content of milk-based formulae ranged from 0.23 to 3.71 ug F/g and for soy-based formulae from 1.08 to 2.86 ug F/g. When reconstituted, according to the manufacturer's directions, with water not containing fluoride, the formulae ranged in fluoride content from 0.031 to 0.532 ppm, with the average fluoride content 0.240 ppm. Using average infant body masses and suggested volumes of formula consumption for infants 1-12 months of age, possible fluoride ingestion per kg body mass was estimated. None of the formulae, if reconstituted using water containing up to 0.1 ppm F, should provide a daily fluoride intake above the suggested threshold for fluorosis of 0.1 mg F/kg body mass. However, if reconstituted with water containing 1.0 ppm F they should all provide a daily fluoride intake of above the suggested threshold for fluorosis with intakes up to 2-3 times the recommended upper 'optimal' limit of 0.07 mg/kg body mass. Under these conditions the water used to reconstitute the formulae would provide 65-97 per cent of the fluoride ingested. These figures are likely to be overestimates due to the intake of nutrients from other sources reducing formulae consumption and also due to the lower bioavailability of fluoride from milk-based formulae. Further, it is generally believed that the maturation stage of enamel formation is the critical period for fluorosis development by chronic, above-threshold fluoride exposure. The maturation stage for the anterior permanent teeth, however, is after the first twelve months of life where fluoride intake from infant formula consumption per kg body mass is highest. The level of fluoride in the commonly used Australian formulae would suggest that infant formula consumption alone is unlikely to be a risk factor for dental fluorosis in a non-fluoridated community, but could make a major contribution to an infant's daily fluoride intake. However, prolonged consumption (beyond 12 months of age) of infant formula reconstituted with optimally-fluoridated water could result in excessive amounts of fluoride being ingested during enamel development of the anterior permanent teeth and therefore may be a risk factor for fluorosis of these teeth.

van Palenstein, Helderman WH, Mabelya L, van't Hof MA, Konig KG, Two types of intraoral distribution of fluorotic enamel. Community Dent Oral Epidemiol, 1997 Jun, 25(3), 251-255

Different distributions of fluorotic dental enamel within the dentition have been described in the literature. This report describes two patterns of intraoral distribution. In nine Tanzanian low fluorosis communities with a prevalence of pitting fluorosis of less than 2% and in five moderate fluorosis communities with a prevalence of pitting fluorosis of 16-59%, incisors and first molars were the least affected teeth. In four high fluorosis communities with a prevalence of pitting fluorosis of 86-97%, maxillary incisors exhibited lower Thylstrup-Fejerskov Index values than the maxillary canines, premolars and molars. The mandibular teeth exhibited increasing Thylstrup-Fejerskov Index values from the anterior to the posterior region. The curves presenting the intraoral distribution of the severity of dental fluorosis corresponded with the curve presenting the completion time of primary enamel formation of the various tooth types, with the exception of the first molars in high fluorosis communities. The similarity of the curves suggests that the later in life enamel is completed, the higher is the severity of dental fluorosis. This relation seems to be explained by the prevailing feeding and dietary habits, which result in minimal intake of fluoride in the first 18 months of life during breastfeeding, followed by increasing fluoride ingestion in the following years through consumption of tea, seafish and F-containing magadi salt.

Warren JJ, Kanellis MJ, Levy SM, Fluorosis of the primary dentition: What does it mean for permanent teeth? JADA 130(3):347-356, 1999

Background. The prevalence of fluorosis of the permanent teeth has increased during the past few decades in the United States and Canada. However, primary-tooth fluorosis has been largely overlooked, because it is often difficult to recognize. This article describes primary-tooth fluo-rosis, both as characterized in the literature and as seen clinically. Methods. The authors review and summarize previous Studies of primary-tooth fluorosis and discuss its etiology. In addition, the authors describe the condition, based on findings from the literature, and their own experiences in characterizing it as part of a longitudinal investigation of fluoride exposures, dental fluorosis and dental caries.

Results. Several studies indicate that primary-tooth fluorosis can be prevalent and severe in areas of very high water fluoride concentrations. In these areas, primary-tooth fluorosis is likely the result of both pre-and postnatal exposures. Studies have documented that primary-tooth fluorosis does occur in areas with optimal or suboptimal water fluoride concentrations, and that in these settings primary-tooth fluorosis is most likely caused by postnatal exposures and is seen most commonly in the primary mo-lars. Primary-tooth fluorosis, however, is often more difficult to identify than fluorosis in permanent teeth, and clinicians may be unfamiliar with its characteristics and may not recognize its somewhat subtle appearance.

Conclusions. Primary-tooth fluorosis may be related to occurrence of fluorosis in the permanent denti-tion, so that its recognition by the clinician should raise awareness of possible increased risk for the permanent dentition.

Clinical Implications. The detection of primary-tooth fluorosis in a young child should prompt the cli-nician to carefully review the child's past fluoride exposures and current fluoride practices, as well as those of any younger siblings. [References: 38]
Reprint: Warren JJ Univ Iowa, Coll Dent, Dept Prevent & Community Dent N-337 Dent Sci Bldg Iowa City, IA 52242 USA

Weeks KJ, Milsom KM, Lennon MA, Enamel Defects In 4-Year-Old to 5-Year-Old Children In Fluoridated and Non-Fluoridated Parts of Cheshire, UK, Fluoride, 1994 Jan, 27(1), 55, from Caries Research, 1993, 27:4 317-320.

The aim of this study was to compare the prevalence of developmental defects of enamel in the deciduous dentition of 4- to 5-year-old children residing in fluoridated (1 ppm F) and non-fluoridated (less than 0.2 ppm Fl communities in Cheshire, UK. The significant difference in the prevalence of developmental defects of enamel between the two communities was accounted for by the higher prevalence of diffuse opacities in fluoridated Nantwich (29%), than in non-fluoridated Northwich (14%). The results also showed that when controlling for the age at which parents claimed toothbrushing commenced, the children in fluoridated Nantwich still had significantly more diffuse defects than the children in Northwich.

Whitford GM, Determinants and mechanisms of enamel fluorosis, Ciba Found Symp, 1997, 205, 226-241.

Enamel fluorosis occurs when fluoride concentrations in or in the vicinity of the forming enamel are excessive during its pre-eruptive development. Fluoride concentrations in plasma, enamel and other tissues reflect the difference between intake and excretion, i.e. fluoride balance. In addition to the diet, modern sources of ingested fluoride include a variety of dental products, some of which have been identified as risk factors for fluorosis. Fluoride absorption is inversely related to dietary calcium which, at high concentrations, may cause net fluoride secretion into the gastrointestinal tract. The excretion of absorbed fluoride occurs almost exclusively via the kidneys, a process which is directly related to urinary pH. Thus, fluoride balance and tissue concentrations and the risk of fluorosis are increased by factors such as high protein diets, residence at high altitude, and certain metabolic and respiratory disorders that decrease pH. Factors that increase urinary pH and decrease the balance of fluoride include vegetarian diets, certain drugs and some other medical conditions. Although several other fluoride-induced effects might be involved in the aetiology of fluorosis, it now appears that inhibition of enzymatic degradation of amelogenins, which may delay their removal from the developing enamel and impair crystal growth, may be of critical importance. In addition to the effects of fluoride, disturbances in enamel formation that can be confused with fluorosis are causedby chronic acidosis and hypoxia independently of the level of fluoride exposure.

Woltgens JH, Etty EJ, Nieuwland WM, Lyaruu DM, Use of fluoride by young children and prevalence of mottled enamel. Advances in Dental Research, 1989 Sep, 3(2):177-82.

The prevalence of mottled enamel in the permanent dentition of children participating in a fluoride (F-) program at the dental school of the Vrije Universiteit (Amsterdam) was investigated in a study utilizing the Thylstrup-Fejerskov (TF) index. The randomly chosen children received a F-regime considered optimal by the Dutch Advisory Committee for Prevention of Oral and Dental Diseases. From the children examined (n = 83; 49 boys and 34 girls; mean age, 13 years and 5 months), 74% exhibited mottled enamel in a slight to moderate degree. More teeth were affected and the degree of mottling was higher when children started to use F- at an earlier age. Unintentional ingestion of toothpaste containing 0.15% F- during frequent toothbrushing in combination with the daily intake of F- tablets before the age of four may explain the high prevalence of mottled enamel. After these treatments, F- concentrations in plasma of young children can reach values which can directly affect the developing tooth germ.

Wright JT, Chen SC, Hall KI, Yamauchi M, Bawden JW, Protein characterization of fluorosed human enamel, J Dent Res, 1996 Dec, 75(12), 1936-1941.

Despite extensive investigation, the development mechanism or mechanisms resulting in dental fluorosis are unknown. Several hypotheses suggest abnormal matrix synthesis, secretion, and delayed and/or defective matrix degradation with retention of enamel protein. The purpose of this study was to characterize the protein composition of fluorosed human enamel. Nine permanent moderately fluorosed (developed in a 3.2 ppm H2O area) and ten permanent normal control teeth (from individuals with < 0.2 ppm F in their drinking water) were evaluated. The enamel fluoride concentration, protein content, and amino acid composition were determined for each tooth. The enamel proteins were further characterized by gel electrophoresis and by Western blot analysis by means of polyclonal antibodies raised against recombinant amelogenin protein. Fluorotic enamel had significantly elevated (p = 0.0001) F levels compared with normal enamel (mean [F-] fluorosed = 431 ppm; mean [F-] control = 62 ppm). While there was a significantly greater protein content by weight in fluorosed enamel compared with normal enamel (mean fluorosed = 0.27%; mean control = 0.11%), the amino acid profiles were similar for fluorosed and normal enamel. Gel electrophoresis showed fluorosed enamel to have a greater diversity of primarily low-molecular-weight proteins compared with normal enamel. Western blot analysis did not indicate retention of amelogenin in either fluorosed or normal enamel. This investigation showed that the protein content of fluorosed enamel was greater than that of normal enamel; however, the amino acid compositions were similar for fluorosed and normal enamel. Furthermore, there does not appear to be retention of significant amounts of amelogenin in fully mature, moderately fluorosed human enamel. Although delayed removal of the enamel matrix proteins may play a role in the hypomineralization defects seen in fluorosed enamel, the majority of these proteins are absent in the mature tissue of these moderately fluorosed teeth.