Trends in the prevalence of dental fluorosis in the United States: a review

Estimated fluoride doses from toothpastes should be based on total soluble fluoride

The fluoride dose ingested by young children may be overestimated if based on levels of total fluoride (TF) rather than levels of bioavailable fluoride (total soluble fluoride—TSF) in toothpaste. The aim of the present study was to compare doses of fluoride intake based on TF and TSF. Fluoride intake in 158 Brazilian children aged three and four years was determined after tooth brushing with their usual toothpaste (either family toothpaste (n = 80) or children’s toothpaste (n = 78)). The estimated dose (mg F/day/Kg of body weight) of TF or TSF ingested was calculated from the chemical analysis of the toothpastes. Although the ingested dose of TF from the family toothpastes was higher than that from the children’s toothpastes (0.074 ± 0.007 and 0.039 ± 0.003 mg F/day/Kg, respectively; p < 0.05), no difference between types of toothpaste was found regarding the ingested dose based on TSF (0.039 ± 0.005 and 0.039 ± 0.005 mg F/day/Kg, respectively; p > 0.05). The fluoride dose ingested by children from toothpastes may be overestimated if based on the TF of the product. This finding suggests that the ingested dose should be calculated based on TSF. Dose of TSF ingested by children is similar whether family or children’s toothpaste is used.

Relative esthetic importance of orthodontic and color abnormalities

OBJECTIVE

To assess the relative importance of an orthodontic esthetic index, dental fluorosis and nonfluoride opacities, with respect to parents' satisfaction with their children's dental esthetics.

MATERIALS AND METHODS

Dental examinations of Iowa Fluoride Study participants assessed fluorosis and nonfluoride opacities in the mixed dentition. Dental casts of 200 randomly selected subjects were scored using the Dental Aesthetic Index (DAI) criteria. Parent satisfaction was assessed via multiple items on a questionnaire. Associations were evaluated using logistic regression.

RESULTS

Nineteen percent of parents were somewhat or very dissatisfied with their children's dental esthetics. Overall DAI score was positively associated with dissatisfaction (P < .001), as was fluorosis (P = .003).

CONCLUSIONS

In addition to changes related to DAI scores, parent esthetic satisfaction decreased with the presence of fluorosis. Dental professionals should address both the issues of tooth positioning and color aberration with respect to dental esthetics.

Changing risk factors for fluorosis among South Australian children

BACKGROUND

Research in the last decade has shown changing exposure patterns to discretionary fluorides and declining prevalence of fluorosis among South Australian children, raising the question of how risk factors for fluorosis have changed.

OBJECTIVE

To examine and compare risk factors for fluorosis among representative samples of South Australian children in 1992/1993 and 2002/2003.

METHODS

Similar sampling strategies and data collection methods were employed in the Child Fluoride Study (CFS) Marks 1 (1992/1993) and 2 (2002/2003). Participants in each CFS round were examined for fluorosis using the Thylstrup and Fejerskov (TF) Index. Exposure history was collected for fluoride in water, toothpaste, fluoride supplements and infant formula, allowing for a fluorosis risk assessment analysis. Data were re-weighted to represent the child population at each time. Changes in prevalence of fluorosis, defined as having a TF score of 1+ on maxillary central incisors, fluoride exposure and risk factors between the two rounds were evaluated.

RESULT

A total of 375 and 677 children participated in the 1992/1993 and 2002/2003 rounds respectively. Prevalence of fluorosis declined significantly from 45.3% to 25.9%. Reduced use of fluoride supplements and increased use of 400-550-ppm children F toothpaste were the most substantial fluoride exposure changes. Early toothpaste use, residence in fluoridated areas and fluoride supplement use were the risk factors in 1992/1993. Early toothpaste use and fluoride supplement use were not risk factors, leaving fluoridated water as the only risk factor among the common variables in 2002/2003. In an analysis stratified by the type of fluoridated toothpaste in 2002/2003, the large amount of toothpaste used was a risk factor in those who used 1000-ppm fluoridated toothpaste, and eating/licking toothpaste when toothpaste use started was a risk factor among children who used either 1000-ppm or 400-550-ppm fluoridated toothpaste.

CONCLUSION

Introduction of the 400-550-ppm F toothpaste and use of smaller amount of toothpaste restricted risk associated with early toothpaste use. Less use and possibly a stricter fluoride supplements regimen also restricted fluorosis risk. Periodic monitoring of risk of fluorosis is required to adjust guidelines for fluoride use in caries prevention.

A half-century of community water fluoridation in the United States: review and commentary

The nearly 50-year history of community water fluoridation is reviewed with the major emphasis on the benefits and safety of fluoridation. Other aspects of water fluoridation also described include the apparent reduction in measurable fluoridation benefits because of the abundance of other fluoride sources, the diffusion of fluoridation effects into fluoride-deficient communities, preeruptive and posteruptive effects, technical and cost aspects, sociopolitical and legal issues that affect the successful fluoridation of communities, and alternatives to community water fluoridation. The majority of studies have evaluated the effectiveness of water fluoridation on the permanent teeth of children, while there are fewer studies on deciduous teeth and in adults; the relationship between fluoride ingestion and bone health needs further clarification; the sociopolitical issues of fluoridation need to be better understood.

Dental fluorosis in children attending basic health units

OBJECTIVES: The purpose of this study was to determine the prevalence and severity of dental fluorosis among patients attending basic health units in Londrina. METHODS: Five basic health units of the urban area were randomly selected and 434 children attending these units, born between 1986 and 1989 (9 to 12 years of age), were examined. Diagnosis of dental fluorosis was performed by means of the Thylstrup and Fejerskov (TF) Index. Oral examinations were carried out by 5 previously trained dentists with the patients lying in the dental chair, under artificial light, preceded by prophylaxis, isolation with cotton rolls and air-drying of the teeth. Ten percent of the sample was reexamined and an almost perfect agreement on diagnostic criteria was obtained either on the intra-examiner or inter-examiner evaluation (K=1.00, p<0.0001). RESULTS: The observed prevalence of dental fluorosis was 91.0%, and 87.8% of the individuals were classified as TF grade 2 or less. CONCLUSIONS: Despite of the low severity, the high prevalence observed shows the need for regular screening of dental fluorosis in Londrina; establishment of procedures to prevent the overutilization of fluoride both by the professionals and the population; sanitary surveillance of fluoride levels in water supply and also in all sources of fluoride available; besides the need for further studies to understand the factors associated to dental fluorosis among children living in Londrina.

Fluoride ingestion from toothpaste: background to European Union-funded multicentre project

As in most other established market economies throughout the world the prevalence of dental caries has declined in most Member States of the European Union (EU). There is evidence that the increased use of fluoride toothpaste has been a major factor in this improvement. Recently there has been increasing debate on the alleged link between increased use of fluoride toothpaste, particularly by infants and young children, and increased levels of enamel fluorosis. Central to these discussions are two issues, namely measurement of the amount of fluoride ingested by infants and young children and measurement of enamel opacities including fluorosis. The aims of the project described in this special issue addressed these two measurement issues. Seven EU Partners participated. Standardized methods for recording the amount of fluoride ingested when using fluoride toothpaste were developed and used in the seven sites. Similarly a standardized photographic method for recording enamel opacities, including fluorosis, was developed.

Parental perception of fluorosis among 8-year-old children living in three communities in Iceland, Ireland and England

OBJECTIVES

To assess the impact of enamel fluorosis in three of the communities examined in 'Project FLINT', it was decided to conduct a structured telephone interview with the parents of some of the children who took part in the study.

METHODS

Three communities involved in this project were able to conduct this investigation: Reykjavik (Iceland), Cork (Ireland) and Knowsley (England). The aim was to interview the parents of children with a range of Thylstrup and Fejerskov (TF) index grades selected from each participating centre with respect to the appearance of their child's permanent maxillary central incisors. Interviewers were blinded as to the TF grade of the subject.

RESULTS

Interviews were conducted with parents of 215 children: 69 with TF grade 0; 70 with TF grade 1; 60 with TF grade 2 and 16 with TF grade 3 or greater. There was a trend towards more parents being unhappy with the appearance of their child's teeth with increasing TF grade. However, the main reasons given by parents for being unhappy with the appearance of their child's teeth was tooth alignment followed by the more yellow colour of permanent compared with primary teeth. Only with a TF grade of 3 was any appreciable concern expressed about fluorosis.

CONCLUSION

It would appear that there is a public awareness of both developmental defects and enamel fluorosis although this is not always expressed as dissatisfaction. Further research is required into the clinical impact of both fluorosis and other developmental defects of enamel.

A comparison of the prevalence of fluorosis in 8-year-old children from seven European study sites using a standardized methodology

OBJECTIVES

The objectives of this study were to report on the prevalence of enamel opacities from seven European study sites using a standardized photographic method, and to investigate the importance of variables responsible for enamel fluorosis.

METHODS

The sample comprised a randomly selected group of 300 8-year-old children in each of the study areas. One examiner from each area was trained and calibrated in the use of a standardized photographic technique. Two transparencies were taken of each child's permanent maxillary central incisor teeth; one to represent the teeth 'wet' and one when the teeth had been allowed to dry out naturally for 105 s. The transparencies were viewed 'blind' by the author (JAC) and scored using the DDE and TF indices. Data relating to variables considered to be associated with enamel fluorosis were also collected.

RESULTS

The prevalence of diffuse opacities ranged from 61% in fluoridated Cork (Ireland) to 28% in Athens (Greece). The percentage of subjects with a TF score of three or more ranged from 4% in Cork and nonfluoridated Haarlem (the Netherlands) to zero in Oulu (Finland) and Athens. Fluoridated water and the prolonged use of fluoride tablets were found to be significant contributory factors to fluorosis.

CONCLUSIONS

The prevalence of fluorosis was found to be highest in fluoridated Cork. The prolonged use of fluoride supplements was also found to be a significant risk indicator associated with fluorosis.

Esthetic perception and psychosocial impact of developmental enamel defects among Malaysian adolescents

The aim of this study was to investigate the prevalence and psychosocial impact of enamel defects among 16-year-old school children on the island of Penang. The data were collected through a self-administered questionnaire survey and an oral examination, using the Modified Developmental Defects of Enamel Index (FDI, 1992). In all, 1024 subjects were selected using a multistage random sampling technique. About two-thirds of the sample (67.1%) had at least one tooth affected by enamel defects. Enamel opacities accounted for 85.6% of the total condition. Diffuse-type opacity predominated (63.5%). Among subjects who expressed dissatisfaction, 18.8% reported covering their mouths when smiling, 8.7% avoided going out with friends and 39.1% had consulted their dentists. About 17% of the subjects reported that their parents had complained about the color of their front teeth but only 5.7% had experienced being teased by their friends about the problem. Two-thirds of the subjects were affected by enamel defects involving at least one tooth; however, the esthetic perception and psychosocial impact of those affected were minor.

Breastfeeding is protective against dental fluorosis in a nonfluoridated rural area of Ontario, Canada

To determine the relationship between early infant feeding and dental fluorosis in a non-fluoridated area, 1367 children were examined for fluorosis and given a water sample vial and questionnaire. 752 families responded (55%). Breastfeeding was reported by 69% of respondents, with 53.6% breastfed < 6 months, 35.3% 6-12 months, and 11.1% > 1 year. Formula feeding was reported by 84% of respondents, with 60.3% and 39.7% formula fed for < 1 year and > 1 year, respectively. Fluorosis prevalence was 23.3% and was present in 27.2%, 19.6% and 13.8% of children breastfed for < 6 months, 6-12 months, and > 12 months, respectively (P < .05). About 87% of formula fed children had tap water added to the bottle. Breastfeeding for > 6 months may protect children from developing fluorosis in the permanent incisors. This study suggests that dental professionals should support efforts to increase the rate and duration of breastfeeding.

Fluoride intake by Brazilian children from two communities with fluoridated water

OBJECTIVES

To determine total daily fluoride intake by young children from two communities in a developing country.

METHODS

Fluoride intake from diet and dentifrice was determined for 71 Brazilian children, aged 19-38 months, living in two communities with fluoridated water (0.6-0.8 ppm). The children from Piracicaba attended a full-time day care centre but those from Ibiá did not. Fluoride ingested during tooth brushing was determined, and 'duplicate-plate' samples of all foods and beverages ingested during a 2-day period were collected from which fluoride for analysis was extracted by hexamethyldisiloxane (HMDS) microdiffusion. The amount of fluoride ingested (mg F/kg body weight/day) from the diet and dentifrice and the combined fluoride intake were calculated. A limit of 0.05-0.07 mg F/kg body weight/day was considered as the safe threshold for fluoride exposure.

RESULTS

The children from Ibiá had lower amounts of fluoride in their diets than those from Piracicaba (P < 0.05); no differences in the amount of fluoride ingested from dentifrice were found between the communities. In both communities, the daily fluoride intake from dentifrice was higher than that from the diet (P < 0.05). Most of the children from both communities were exposed to a combined dose (diet + dentifrice) of fluoride above the risk threshold for dental fluorosis.

CONCLUSION

The data suggest that fluoride intake from diet depends on living conditions, and measures should be implemented to reduce the fluoride intake of these Brazilian children.

Fluoride intake from foods, beverages and dentifrice by children in Mexico

OBJECTIVES

This investigation monitored fluoride ingestion in Mexican children who were susceptible to developing dental fluorosis.

METHODS

Total fluoride intake, from dietary and toothpaste samples, was determined in 15-36-month-old children from Mexico City and Veracruz, Mexico. A duplicate plate technique was used. Plasma fluoride levels were also determined in this group of children.

RESULTS

The children ingested a mean (+/-SD) of 0.20 +/- 0.08 and 0.18 +/- 0.07 mg fluoride/kg/day, in Mexico City and Veracruz, respectively. There was no statistically significant difference between the fluoride ingested by children in the two cities (P > 0.9). Plasma from children in Mexico City and Veracruz contained a mean of 1.30 +/- 0.81 and 0.87 +/- 0.72 micro mol fluoride/l, respectively, and these values were not significantly different.

CONCLUSIONS

Our results lead to the conclusion that mean fluoride ingested from the combination of foods and beverages was within the proposed safe threshold for fluoride intake of 0.05-0.07 mg F/kg/day. Most of the fluoride intake by these children was derived from the ingestion of fluoridated toothpaste. When all sources of ingested fluoride were added and total fluoride intake was calculated, the children, both in Mexico City and Veracruz, were ingesting amounts of fluoride well above the upper limits of the proposed safe threshold for fluoride intake.

Current and future role of fluoride in nutrition

Fluoride continues to be the cornerstone of dental caries prevention in North America and throughout the world, and there are a variety of sources of fluoride that may contribute to the dietary intakes of fluoride. Although the severe effect of chronic exposures to high levels of fluoride--skeletal fluorosis--is extremely rare in North America, dental fluorosis has become more prevalent. To address the increase in dental fluorosis prevalence, recommendations have been made to reduce fluoride ingestion early in life. These recommendations have included the introduction of lower concentration fluoride dentifrice for use by young children, labeling of the fluoride concentration of bottled water, and revised fluoride supplement guidelines to reduce or eliminate their use. Because our knowledge is incomplete regarding the amount, duration, and timing of fluoride ingestion that can result in dental fluorosis, however, further research is clearly needed before definitive recommendations can be made regarding the use of fluorides, including recommended intakes of fluoride in the diet.

Fluorosis development in seven age cohorts after an 11-month break in water fluoridation

This study used an 11-month break in water fluoridation to identify the time when developing incisors are most sensitive to fluorosis development. The study was based in Durham, NC, where an interruption to water fluoridation occurred between September, 1990, and August, 1991. A total of 1896 children was dentally examined. Fluorosis was measured by the TF index, and parents or guardians completed a questionnaire on demographics and fluoride history. Age cohorts ranged from those born 5 years before the break, to those born 1 year after the resumption of fluoridation. Fluorosis prevalence for seven age cohorts whose birth years ranged from 1985-86 to 1991-92 was 57.1, 62.3, 33.0, 32.3, 39.8, 30.2, and 36.8%, respectively. Children aged from birth to 3 years at the break, and those born 1 year after it, had less fluorosis than those aged 4-5 years at the break.

The fluoride content of foods and beverages from negligibly and optimally fluoridated communities

In the spring of 1996, foods and beverages most commonly consumed by adolescents were analyzed for fluoride as part of a larger investigation. These foods were selected by interviewing 711 adolescents, 12-14 years of age, who were long-time residents of either an optimally or negligibly fluoridated community. The brand names of the identified foods and beverages most commonly purchased were determined by interviews with the parents. A total of 441 brand-name food and beverage items were purchased from both communities and were individually analyzed for fluoride. These analyses were done in order to estimate the fluoride content of various kinds of foods and beverages and to determine whether or not there was a significant difference between the two communities in the amount of fluoride ingested from these dietary sources. The food and beverage items were classified into dietary groups based on US Department of Agriculture (USDA) guidelines. Overall, the fluoride content of the sampled foods and beverages was low. In addition, there was no significant difference in the fluoride content of the same pre-packaged or ready-to-eat food or beverage items purchased in the two communities. However, a significant difference was found between the two communities in the fluoride content of fountain beverages and in cooked or reconstituted foods prepared using local water from the respective communities. Based on these results, we have estimated the mean daily, dietary fluoride intake for 3-5-year-old children who are more susceptible to developing dental fluorosis.

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.

A pilot study of dental students' esthetic perceptions of computer-generated mild dental fluorosis compared to other conditions

OBJECTIVES

Few studies have considered people's opinions about the esthetics of dental fluorosis. Assessments of fluorosis esthetics can be confounded by differences in a number of clinical factors, including tooth shape, color, contour, and gingival status. This pilot study compared esthetic perceptions of mild fluorosis and other conditions using computer-generated images made from a base set of normal appearing teeth.

METHODS

Entering dental students (n = 61) completed questionnaires about four sets of paired photographs. Three sets consisted of fluorotic teeth (very mild to mild) versus other conditions (diastema, isolated enamel opacity, "normal"/control) and the other pair compared two presentations of mild fluorosis (generalized versus limited to incisal one-third). Six questions, both qualitative and quantitative, were asked about each pair of photographs.

RESULTS

Mild fluorosis was assessed less favorably than normal/control, midline diastema was less favorable than mild fluorosis, and mild fluorosis was less favorable than isolated opacity.

CONCLUSIONS

This approach allows fluorosis to be better compared with other oral conditions because the images are standardized. Additional research with this method is warranted, including more variations in conditions, more comparisons, and other study populations.

Water consumption in the United States in 1994-96 and implications for water fluoridation policy

OBJECTIVES

The purpose of this project was to describe current water consumption patterns and to compare them to findings from earlier studies. Current water consumption data also were used to reevaluate the association between water consumption and climate. These findings are of importance in estimating fluoride intake from fluoridated water.

METHODS

Findings from the 1994-96 Continuing Survey of Food Intakes by Individuals (CSFII) were compared to those from two earlier dietary studies, the 1977-78 Nationwide Food Consumption Survey (NFCS) and the pioneering research of Galagan and colleagues in the 1950s. Food consumption data were analyzed for 14,619 persons with food and beverage intake data for two 24-hour periods in the CSFII.

RESULTS

Increased consumption of infant formulas and decreased consumption of tap water and cow's milk were seen in the CSFII for infants compared to the NFCS. Older children and adults showed increased consumption of carbonated beverages and juices. While Galagan and colleagues found about a 60 percent increase in water consumption between the coldest (55 degrees F) and warmest (85 degrees F) conditions, only a 20 percent difference was seen between the winter and summer months in certain regions in the CSFII.

CONCLUSIONS

No obvious strong or consistent association between water intake and month or season was apparent in these recent data. These findings are preliminary, and suggest that water fluoridation policy requires further research regarding water consumption and climate.

Dietary effects on dental diseases

Dental caries is a highly prevalent chronic disease and its consequences cause a lot of pain and suffering. Sugars, particularly sucrose, are the most important dietary aetiological cause of caries. Both the frequency of consumption and total amount of sugars is important in the aetiology of caries. The evidence establishing sugars as an aetiological factor in dental caries is overwhelming. The foundation of this lies in the multiplicity of studies rather than the power of any one. That statement by the British Nutrition Foundation's Task Force on Oral Health, Diet and Other Factors, sums up the relationship between sugars and caries in Europe. There is no evidence that sugars naturally incorporated in the cellular structure of foods (intrinsic sugars) or lactose in milk or milk products (milk sugars) have adverse effects on health. Foods rich in starch, without the addition of sugars, play a small role in coronal dental caries. The intake of extrinsic sugars beyond four times a day leads to an increase risk of dental caries. The current dose-response relationship between caries and extrinsic sugars suggests that the sugars levels above 60 g/person/day for teenagers and adults increases the rate of caries. For pre-school and young children the intakes should be proportional to those for teenagers; about 30 g/person/day for pre-school children. Fluoride, particularly in toothpastes, is a very important preventive agent against dental caries. Toothbrushing without fluorides has little effect on caries. As additional fluoride to that currently available in toothpaste does not appear to be benefiting the teeth of the majority of people, the main strategy to further reduce the levels of caries, is reducing the frequency of sugars intakes in the diet. Dental erosion rates are considered to be increasing. The aetiology is acids in foods and drinks and to a much lesser extent from regurgitation.

Prevention of dental disease. The role of the pediatrician

Evidence increasingly suggests that to be successful in preventing dental disease, we must begin preventive interventions within the first year of life. Pediatricians are well positioned to begin this process with early assessment of oral health and provision of anticipatory guidance, including ensuring that patients establish a dental home in addition to their medical home. This article provides information that will enable pediatricians to assess caries risk and provide practical and effective advice to parents about preventing dental disease, including oral hygiene, diet, and fluoride recommendations.

Dental fluorosis in permanent incisor teeth in relation to water fluoridation, social deprivation and toothpaste use in infancy

OBJECTIVES

To determine the prevalence and severity of fluorosis in permanent incisor teeth in young children in a fluoridated and a fluoride-deficient community and to establish what relationship, if any, there was between the occurrence of dental fluorosis and the reported use of fluoride toothpaste in childhood.

DESIGN

A prevalence study of children aged 8-9 years who had been continuous residents in fluoridated Newcastle or fluoride-deficient Northumberland.

METHOD

The permanent maxillary central incisor teeth were examined clinically and photographically by one examiner using the Thylstrup-Fejerskov index; the photographs were read blind to child identity and clinical score. A closed-response questionnaire enquired into the child's early experiences of toothbrushing and use of fluoride toothpastes. Social deprivation was measured by a Jarman score. The study took place in 1998.

OUTCOME MEASURE

Prevalence of dental fluorosis measured by the Thylstrup-Fejerskov index.

RESULTS

Complete data were available for 78% (n = 409) and 79% (n = 403) of eligible sampled children in the two areas, respectively. Clinical and photographic results agreed closely and had high reproducibility. The prevalence of fluorosis was 54% in the fluoridated area and 23% in the fluoride-deficient area when all grades (> 0) of fluorosis were included; percentage prevalence of mild to moderate fluorosis (> or = 3) was 3% and 0.5% in the two areas, respectively. Multivariate analysis indicated that area of residence (odds ratio = 4.5), Jarman score (odds ratio = 0.99 per Jarman unit) and type of toothpaste (odds ratio = 1.6) were statistically significantly related to presence or absence of fluorosis: the risk factors were--fluoridated area, affluence, and use of adult toothpaste.

CONCLUSIONS AND RECOMMENDATIONS

The prevalence of aesthetically important dental fluorosis was low, although higher in the fluoridated area. Use of a child's toothpaste (with lower fluoride concentration) could decrease risk in a fluoridated area. Adherence to the guidelines published by the British Society of Paediatric Dentistry is recommended.

The prevalence and severity of enamel fluorosis in North American children

The question considered in this review is the extent to which changes in the prevalence or severity of enamel fluorosis have occurred over the last half-century. Emphasis is given to a review of those studies in which subjects are drinking water that is fluoride deficient and those in which subjects are drinking optimally fluoridated water, either adjusted or natural. Trends in fluorosis were examined using two definitions of fluorosis (definite and any signs) and three types of comparisons--comparisons of pooled estimates from all available studies that include data from different communities and time periods, comparisons of estimates from the same communities at different times, and comparisons of estimates from selected studies in the early years of fluorosis research with results of the US National Fluorosis Survey done by the National Institute of Dental Research. A clear increase in fluorosis among populations drinking community water that contains less than 0.3 ppm fluoride was found. Results of the comparisons using studies with Dean's Index pooled at different time points, comparisons in the same communities over time, and comparisons of prevalence found in selected communities before fluoride was widely available with the National Fluorosis Survey all support this conclusion. An increase in the prevalence of fluorosis in those drinking optimally fluoridated water likely has occurred as well; however, evidence for such a trend is not as clear as for fluoride deficient communities because of mixed results depending on the type of comparison. The majority of fluorosis cases continue to be mild and seem of little esthetic consequence for most of the public or dental profession. But a few cases of more severe fluorosis can be found now in some communities. Because the prevalence of fluorosis is now higher than 50 years ago, we can conclude that fluoride availability to the developing enamel during critical periods when enamel is at risk of fluorosis has increased in North American children.

The case for retaining the current supplementation schedule

Following ingestion of dietary fluoride, microquantities of fluoride return to the mouth in saliva, but in quantities large enough to facilitate the maintenance and reparative functions of enamel. Dietary fluoride supplements alone are unlikely to be the cause of the reported increase in fluorosis. Compliance continues to be extremely poor and few children use supplements for more than a year and a half. The amount of background fluoride resulting from dietary fluoride supplements appears to be very small. Considering the almost ubiquitous presence of fluoride dentifrice and the strong possibility of additional unintentional fluoride ingestion from many sources, the present fluorosis data is too amorphous to use as a basis for making reasonable risk/benefit evaluations. Very mild and mild fluorosis is not a serious problem for either the clinician or the patient. By altering the present recommended dosage we may deprive children from receiving a proven effective dose. One cannot make a risk/benefit decision concerning an esthetic problem without involving the patient's perception as well as the caries score. The apparent severity of the milder forms of fluorosis lessens with age and a community fluorosis index should be used only on populations who are older than 15 years.

The effects of a break in water fluoridation on the development of dental caries and fluorosis

Durham, NC, fluoridated since 1962, had an 11-month cessation of fluoridation between September, 1990, and August, 1991. The purpose of this study was to assess the effects of this break on the development of caries and fluorosis in children. Study participants were continuously-resident children in Kindergarten through Grade 5 in Durham's elementary schools. There were 1696 children, 81.4% of those eligible, for whom a questionnaire was completed and clinical data recorded. Age cohorts were defined by a child's age at the time that fluoridation ceased. Caries was recorded in children in the Birth Cohort through Cohort 3, and fluorosis for children in Cohorts 1 through 5. Caries was assessed in the primary first and second molars according to the decayed-filled index; fluorosis on the labial surfaces of the upper permanent central and lateral incisors was assessed by the Thylstrup-Fejerskov (TF) index. Mother's education was associated with caries; higher education of the mother had an odds ratio of 0.53 (95% CI 0.40, 0.76) for caries in the child. No cohort effects could be discerned for caries. Overall prevalence of fluorosis was 44%. Prevalence in Cohorts 1, 2, 3, 4, and 5 was 39.8%, 32.3%, 33.0%, 62.3%, and 57.1%, respectively. These cohort differences remained statistically significant in regression analysis. It was concluded that while the break had little effect on caries, dental fluorosis is sensitive to even small changes in fluoride exposure from drinking water, and this sensitivity is greater at 1 to 3 years of age than at 4 or 5 years.

Fluoride intake from foods, beverages and dentifrice by young children in communities with negligibly and optimally fluoridated water: a pilot study

While the level of fluoride intake that affords optimal cariostatic efficacy without causing dental fluorosis is not precisely known, it has been suggested that the threshold of fluoride exposure above which fluorosis may occur is between 0.05 and 0.07 mg/kg/day.

OBJECTIVE

To monitor and compare fluoride intake from diet and dentifrice use (theoretical F: 0.10-0.11%) by three groups of 16- to 40-month-old children: two groups living in the negligibly water-fluoridated communities of San Juan, Puerto Rico, and Connersville, Indiana, and the third group residing in the optimally water-fluoridated region of Indianapolis, Indiana.

METHODS

Fluoride intake from diet was monitored by the "duplicate plate" method, and fluoride ingested from dentifrice was determined by subtracting the amount of fluoride recovered after brushing from the amount originally placed on the child's toothbrush.

RESULTS

The mean combined amount of fluoride ingested daily by children living in the negligibly fluoridated communities was not significantly different from that ingested by children in the fluoridated community. The major component of fluoride ingested by children in the negligibly fluoridated communities came from fluoridated dentifrice, and in the fluoridated area children ingested as much fluoride from toothpaste as they did from beverages. In San Juan mean daily fluoride intake was within the estimated range for safe fluoride exposure; however, in the "halo" community of Connersville and in Indianapolis, daily fluoride ingested by many of the children may have exceeded this level.

CONCLUSION

Attention needs to be given, in negligibly water-fluoridated as well as in optimally water-fluoridated communities, to reducing the daily intake of fluoride by young children in order to avoid putting them at risk of developing dental fluorosis.

Dental fluorosis among persons exposed to high- and low-fluoride drinking water in western Norway

The aim of this project was to study the prevalence and severity of dental fluorosis among persons exposed to moderate- to high- or low-fluoride drinking water in western Norway, and to assess the risk factors involved. Subjects aged 5 to 18 years who had been lifelong consumers of moderate- to high-fluoride groundwater (> or = 0.50 mg F/L) were selected for the study (n = 113). A comparison group (n = 105) was chosen among consumers of low-fluoride surface water (approximately 0.10 mg F/L) in the same district. The Thylstrup-Fejerskov (TF) Index was used to score dental fluorosis. A questionnaire was used to obtain information on fluoride exposure and other relevant factors. Among the consumers of low-fluoride water 14.3% showed dental fluorosis (TF score 1-2) as compared to 78.8% in the group consuming moderate- to high-fluoride water (TF scores 1-7). Premolars were most frequently affected, but severe cases (TF scores 3-7) were equally prevalent in maxillary central incisors and first molars. In logistic regression analysis with TF score 0 or TF score > or = 1 as the dependent variable, only fluoride concentration in the drinking water was associated with a statistically increased risk of dental fluorosis (odds ratio: 18.9; 95% CI: 8.85-40.44). In the study area, which was characterised by multiple fluoride sources, uncontrolled groundwater with moderate to high fluoride content was the most important factor in the development of dental fluorosis. In order to prevent dental fluorosis, groundwater wells should routinely be analysed for fluoride.

Fluorosis risk in grade 2 students residing in a rural area with widely varying natural fluoride

OBJECTIVES

This pilot study was performed to determine the prevalence of dental fluorosis and the association between fluorosis and a number of risk factors in a group of second grade students in a rural, non-fluoridated area of Ontario, Canada.

METHODS

Of 1739 students screened during routine health surveillance, 1367 had erupted maxillary central incisors. Fluorosis was scored on these children using the Tooth Surface Index of Fluorosis (TSIF). A fluoride exposure questionnaire and water sample vial was sent home from school with each child.

RESULTS

Valid responses were obtained for 752 children (55%). The prevalence of fluorosis in respondents was 23.3%, with 4.9% scoring TSIF of 2 or more. In bivariate analysis, several variables were significantly associated with the prevalence and/or severity of fluorosis. These included: water fluoride concentration, breast-feeding duration, professionally applied topical fluoride, fluoride supplement use, bottle-feeding, fluoridated mouthwash use, and early parental toothbrushing with toothpaste. In logistic regression analysis limited to children living at the current residence for 4 years or more, only four variables had significant independent effects. These were water fluoride concentration, breast-feeding duration, fluoride supplement use, and fluoridated mouthwash use.

CONCLUSIONS

These findings indicate that fluorosis is an important concern in non-fluoridated areas. Fluoride supplements should not be recommended unless an independent home water test is performed. Breast-feeding for 6 months or more may protect children from developing dental fluorosis in the permanent incisors.

Changes in dental fluorosis and dental caries in Newburgh and Kingston, New York

OBJECTIVES

This study sought to determine whether the prevalence of dental fluorosis and dental caries had changed in a fluoridated community and a nonfluoridated community since an earlier study conducted in 1986.

METHODS

Dental fluorosis and dental caries data were collected on 7- to 14-year-old lifelong residents (n = 1493) of Newburgh and Kingston, NY.

RESULTS

Estimated dental fluorosis prevalence rates were 19.6% in Newburgh and 11.7% in Kingston. The greatest disparity in caries scores was observed between poor and nonpoor children in nonfluoridated Kingston.

CONCLUSIONS

The prevalence of dental fluorosis has not declined in Newburgh and Kingston, whereas the prevalence of dental caries has continued to decline.

Fluorosis risk from early exposure to fluoride toothpaste

Swallowed fluoride toothpaste in the early years of life has been postulated to be a risk factor for fluorosis, but the epidemiological evidence is weakened by the fact that most of the relevant studies were done in developed countries where an individual is exposed to multiple sources of fluoride.

OBJECTIVES

To quantify the risk of fluorosis from fluoride toothpaste in a population whose only potential source of fluoride was fluoride toothpaste.

METHODS

Case-control analyses were conducted to test the hypothesis that fluoride toothpaste use before the age of 6 years increased an individual's risk of fluorosis. Data came from a cross-sectional clinical dental examination of schoolchildren and a self-administered questionnaire to their parents. The study was conducted in Goa, India. The study group consisted of 1189 seventh grade children with a mean age of 12.2 years.

RESULTS

The prevalence of fluorosis was 12.9% using the TF index. Results of the crude, stratified, and logistic regression analyses showed that use of fluoride toothpaste before the age of 6 years was a risk indicator for fluorosis (OR 1.83, 95% CI 1.05-3.15). Among children with fluorosis, beginning brushing before the age of 2 years increased the severity of fluorosis significantly (P<0.001). Other factors associated with the use of fluoride toothpaste, such as eating or swallowing fluoride toothpaste and higher frequency of use, did not show a statistically significant increased risk for prevalence or severity of fluorosis.

CONCLUSIONS

Fluoride toothpaste use before the age of 6 years is a risk indicator for fluorosis in this study population.

Parents' satisfaction with children's tooth color: fluorosis as a contributing factor

The authors surveyed parents of 708 patients in a pediatric dental practice about their satisfaction with the color of their children's teeth and factors associated with their level of satisfaction. Overall, 43 percent of parents were dissatisfied with their children's tooth color, and 78 percent of children had a Tooth Surface Index of Fluorosis, or TSIF, score greater than 0. The worst TSIF score was the only factor associated with parent satisfaction.

Dental caries and dental fluorosis among schoolchildren who were lifelong residents of communities having either low or optimal levels of fluoride in drinking water

OBJECTIVE

This paper reports findings for dental caries and dental fluorosis in 8-10- and 13-16-year-old schoolchildren who were lifelong residents of communities having either naturally occurring low (Broken Bow and Holdrege, NE; < 0.3 ppm) or optimal (Kewanee, IL; 1 ppm) levels of fluoride in drinking water.

METHODS

Findings are reported for participants who received both dental caries and dental fluorosis examinations (n = 495). The DMFS and TSIF indices, respectively, were used to assess dental caries and dental fluorosis.

RESULTS

The mean DMFS score adjusted for age, sealant presence, and fluoride use was significantly lower in Kewanee (1.8) than was the adjusted mean caries score in either Holdrege (2.9) or Broken Bow (3.6). Adjusted mean DMFS scores in Broken Bow and Holdrege were not statistically different. The mean percent of fluorosed tooth surfaces per person, adjusted for age and use of dietary fluoride supplements, was similar in the three communities (approximately 15%); more than 80 percent of tooth surfaces in all participants were fluorosis-free.

CONCLUSIONS

Findings from the present study suggest that water fluoridation still is beneficial and that dental sealants can play a significant role in preventing dental caries. In addition, findings from this survey appear to support the premise that the difference in dental fluorosis prevalence between fluoridated and nonfluoridated communities has narrowed considerably in recent years.

Dental caries and dental fluorosis at varying water fluoride concentrations

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 lower 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.

Fluoride concentrations of infant foods

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.

Determinants and mechanisms of enamel fluorosis

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 caused by chronic acidosis and hypoxia independently of the level of fluoride exposure.

Protein characterization of fluorosed human enamel

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.

Assessing fluoride concentrations of juices and juice-flavored drinks

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.

The effectiveness of community water fluoridation in the United States

Grand Rapids, the first city in the world to implement controlled water fluoridation, has served as a model for thousands of other communities. Fluoridation is one of the greatest public health and disease-preventive measures of all time. Its advantages include effectiveness for all, ease of delivery, safety, equity, and low cost. Today, nearly 56 percent of the US population lives in fluoridated communities (62% of those on central water supplies). Previously observed caries reductions of one-half to two-thirds are no longer attainable in the United States because other fluoride methods and products have reduced the caries prevalence in all areas, thus diluting the measurement of effectiveness, and because benefits of fluoridation are dispersed in many ways to persons in nonfluoridated areas. Water fluoridation itself, however, remains as effective as it ever was among groups at high risk to dental caries. Contrary to early beliefs that stressed the importance of preeruptive fluoride exposure, fluoridation also provides an important source of topical fluoride and facilitates remineralization. Although data on effectiveness and safety are compelling, future progress of water fluoridation will be affected by economic, political, and public perception factors.

Infants' fluoride ingestion from water, supplements and dentifrice

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.

Risk factors for dental fluorosis in pediatric dental patients

OBJECTIVES

Concerns have been raised recently about whether a substantial amount of dental fluorosis is resulting from the increased use of fluoride from various sources. The purposes of this study were to determine the prevalence and severity of dental fluorosis in a sample of pediatric patients seeking dental treatment in a university pediatric dental clinic and to evaluate sources of fluoride as risk factors for dental fluorosis.

METHODS

A convenience sample of 157 children aged 8 to 17 years were examined for dental fluorosis using the Tooth Surface Index of Fluorosis (TSIF). Fluoride history questionnaires assessing previous exposure to fluoride during the first eight years of life were completed by the children's parents. Fluoride exposures were compared among 54 cases and 54 matched controls using a case-control retrospective design.

RESULTS

Fluorosis was found in 72 percent of the children, but was generally quite mild. The risk of fluorosis was significantly greater for children who had greater exposure to fluoridated water and who used larger amounts of fluoridated toothpaste up to age eight.

CONCLUSIONS

This study provided evidence that increased use of fluoride toothpaste may be a risk factor for dental fluorosis. The results suggest prudent use of dentifrice by young children to minimize the risk of fluorosis.

Dental fluorosis and caries prevalence in children residing in communities with different levels of fluoride in the water

OBJECTIVES

This study investigated the prevalence of dental fluorosis and caries in 7-14-year-old children residing in communities with negligible (NF: 0.2 ppm), optimal (OPF: 1.0 ppm), and four-times optimal (4X OPF: 4.0 ppm) naturally occurring fluoride in their water systems.

METHODS

Examinations were performed on 344 children who were lifetime residents of their communities.

RESULTS

Whether using the tooth surface index of fluorosis or Dean's index, children examined in the 4X OPF community had the highest prevalence of dental fluorosis. While the severity of fluorosis seen in the OPF and NF communities was mild in appearance, the results indicate that fluorosis does occur in optimally and negligibly fluoridated communities. Compared to the NF community, DMFT and DMFS scores in the OPF community were 9.2 percent and 21.2 percent lower, respectively.

CONCLUSIONS

The ingestion of water containing 1 ppm or less fluoride during the time of tooth development may result in dental fluorosis, albeit in its milder forms. However, in these times of numerous products containing fluoride being available, children ingesting water containing 1 ppm fluoride continue to derive caries protection compared to children ingesting water with negligible amounts of fluoride. Thus, the potential for developing a relatively minor unesthetic condition must be weighed against the potential for reducing dental disease.

Prevalence of dental caries and dental fluorosis in areas with optimal and above-optimal water fluoride concentrations: a 10-year follow-up survey

OBJECTIVES

This paper presents findings for dental caries and fluorosis from an October 1990 follow-up survey in Illinois and compares results with those obtained from two similar school-based examinations conducted in 1980 and 1985 within the same communities.

METHODS

The seven study sites were grouped into four categories according to the approximate relation of their water fluoride concentration to the recommended optimal fluoride level for the area. Tests for differences in dental caries and dental fluorosis across the four water fluoride groupings and three examinations were conducted.

RESULTS

DMFS scores for children who resided in communities with above-optimal water fluoride levels did not change significantly from 1980 through 1990. At the optimal water fluoride concentration, caries scores did not change substantially from 1980 to 1985; however, the mean DMFS score in 1990, 1.9, was significantly lower than caries levels observed during the two previous exams. In the optimally fluoridated area, the proportion of fluorosed tooth surfaces increased significantly from 1980 to 1985, but then declined by 1990 to the level observed in 1980 for both age groups.

CONCLUSIONS

The results suggest that: (1) in the optimally fluoridated community, the apparent increase in the prevalence of dental fluorosis observed from 1980 to 1985 did not continue from 1985 to 1990; and (2) at above-optimal water fluoride concentrations, dental fluorosis either remained stable or demonstrated no sustained increase over the decade.

Commentary on and recommendations for the proper uses of fluoride

Fluorosis has been associated with the fluoride concentration of drinking water, use of dietary fluoride supplements, early use of dentifrices, and prolonged use of infant formula. The literature, however, does not show associations between fluorosis and use of fluoride mouthrinses, professionally applied fluorides, bottled waters, carbonated beverages, and juices. It is unwise to issue laundry lists of items that may be implicated as problem-causing when, in fact, they may not be. Although usually classified without fluorosis, children in Dean's "questionable" category would be classified with the condition if the TFI or TSIF were used. Accordingly, Dean, in 1942, really reported only 52.8 percent of children without fluorosis in Kewanee, a community with 0.9 ppm fluoride in drinking water. Because the morbidity and sequelae of dental caries have declined, undue emphasis has been placed recently on the risks of using fluoride rather than on its profound beneficial effects. Although of paramount importance, conclusions cannot be drawn on whether fluoride protects against, contributes to, or has no effect on bone fractures or is valuable in treating osteoporosis. Careful thought is required before making recommendations that may reduce health benefits because of unfounded concerns about perceived risks. There should be greater regulation of extraneous fluoride sources, rather than reliance on educational efforts or recommendations to eliminate use of highly effective preventive regimens.

Influence of exposure to various fluoride technologies on the prevalence of dental fluorosis

An increase in the prevalence of dental fluorosis among children in North America is well documented. Published reports of the relationship between the occurrence of dental fluorosis and early exposure to various fluorides and the use of different types of infant feeding practices have begun to provide insights into possible causes for this increase. This study was designed to investigate this issue for children living in a non-fluoridated and a fluoridated community in British Columbia, Canada. Parents or guardians completed a questionnaire which detailed exposure to different types of fluorides and infant feeding practices during the first 6 yr of life. Completed questionnaires were returned and examinations were performed on 1131 children. 60% of children had dental fluorosis, and only 8% presented with scores of 2 or greater. Logistic regression analyses showed that the use of infant formula and parental educational attainment were significantly associated with the occurrence of dental fluorosis in the range of scores from 2 to 6. Despite these statistically significant findings, these variables actually had little additional predictive value beyond a chance occurrence in determining which children would have dental fluorosis.