Risk Factor For Dental Fluorosis Research Articles

FLUOROSIS PREVALENCE AT DIFFERENT REGIONS OF THE EARTH (LITERATURE REVIEW)

The aim of the study is to analyze the literature about the fluorosis prevalence and the factors which lead to dental and bone fluorosis. The search for articles published in 2016-2023 was conducted by the authors in Scopus and Web of Science scientific data bases using the keywords “fluorosis”, “dental fluorosis”. To classify the severity of dental fluorosis, the index of developmental defects of enamel (DDE), the index of tooth surface fluorosis (TSIF), and mostly Dean’s index Thylstrup & Fejerskov Index (TFI) are used. The risk factors for dental fluorosis include living in regions with high level of fluoride, drinking water with high level of fluoride or salt fluoridation, drinking bottled water, use of fluoride toothpastes among preschool children, early weaning, and use of infant formula for long time, and, as well as, a hot climate and high fluoride content in soil and food. The studies from India and China demonstrated that the average concentration of dental fluorosis and skeletal fluorosis at fluoride contained 6 mg/l. The prevalence of dental fluorosis in NorthernTanzania, where the fluorine content in daily drinking water is 3.6 mg/l, reaches 75,22%. In Ethiopia, where fluorine content is 5.09 mg/l, the prevalence of skeletal fluorosis ranges from 55.1% to 72.4%. In Kenya, the fluoride content in drinking water reaches 72 mg/l, so the prevalence of dental fluorosis is 80%. The prevalence of dental fluorosis is lower in South Western Saudi Arabia and Iran where fluoride level is lower. In Jordan, the prevalence of dental fluorosis reaches 39.9% due to the high fluoride content in miner rocks. Skeletal fluorosis is wide spread in some areas of Pakistan due to the contamination of ground water by industrial production. The prevalence of mild dental fluorosis is 39% in New castle where water is fluoridated, and 24% in non-fluoridated Manchester in England. Dean’s index and TFI index are mostly used to classify these variety of fluorosis. Various factors affect the appearance of dental and bone fluorosis worldwide, so the prevalence of fluorosis varies from 11,1 up to 100%.

Evaluation of Fluoride Concentration in Commercially Available Bottled Water in Romania—A Potential Risk Factor for Dental Fluorosis

Fluoride (F) ions actively participate in the dental enamel remineralisation process and inhibit the activity of cariogenic bacteria of the oral biofilm. However, increased systemic intake of F during critical periods of amelogenesis can lead to dental fluorosis (DF). The necessity of our study stemmed from the growing consumption of bottled water, as water is one of the primary sources of F in humans, and labelling F concentration is optional. Our aim was to evaluate the F concentration in bottled natural mineral or spring still waters available on the market in Iasi, Romania. We purchased forty different brands of still bottled water from the major grocery stores and tested them using an ion-selective electrode method. The reliability of the data was assessed by the intraclass correlation coefficient (ICC), while the differences between the obtained and labelled F values were examined using a paired samples t-test. The tested F levels ranged between 0.0338 and 4.6262 milligrams per litter (mg/L). The majority of the samples, around 85% recorded F values ranging from 0.232 to 0.0338 mg/L, offering slight or no benefit in caries prevention. Another 10% of the samples had F values ranging between 0.3 and 0.4 mg/L and could provide a dental health benefit. A percentage of 5% of the tested samples recorded F levels above the optimal level of 0.7 mg/L, as set by the American Dental Association (ADA) and the United States Department of Health and Human Services (U.S. HHS). This elevated F concentration poses a potential risk for DF in infants and toddlers, indicating that regular consumption of these samples may be unsafe.

Toothbrushing practices as risk factors for dental fluorosis in an area with varying fluoride levels in drinking water.

Despite contributing to a reduction in dental caries, improper use of fluoridated toothpaste could add to the burden of dental fluorosis in children. To assess the association between tooth-brushing practices such as the type and amount of toothpaste used, frequency of tooth brushing, parental assistance in tooth brushing, timing of tooth brushing and dental fluorosis in school children in Kurunegala district, an endemic area for dental fluorosis in Sri Lanka. For this case-control study, a sex-matched sample of 15-year-old school children attending government schools in Kurunegala district and who were lifetime residents of the district was selected. Dental fluorosis was measured using the Thylstrup and Ferjeskov (TF) Index. Those children with a TF⟩1 were considered as cases and those with a TF score of 0 or 1 served as controls. An interview of parents/caregivers of the participants was used to assess risk factors for dental fluorosis. The fluoride concentration in drinking water was measured using spectrophotometry. Data analysis used chi-square tests and conditional logistic regression. Tooth brushing ≥ twice/day, brushing after breakfast and parent/care giver brushing the child's teeth reduced the likelihood of developing fluorosis. Use of fluoridated toothpaste adhering to the recommended guidelines could prevent dental fluorosis in children in this endemic area.

A comparative evaluation of the fluoride content in commercially available infant formulae in India: An in vitro study.

The most critical period for enamel fluorosis to develop is during the early years of life when enamel formation occurs. To minimize the risk of dental fluorosis development, monitoring fluoride intake during teeth development has been suggested. As infant formulae are major source of nutrition in infants, it is important to determine the fluoride content in them in order to monitor the fluoride intake in infants. To estimate and comparatively evaluate the fluoride content in different commercially available infant formulae in India. A total of 16 commercially available infant formulae were collected from local pharma/grocery stores, in which 14 were milk based (Group M) and 2 were soy based (Group S). Fluoride content of the formulae was evaluated using ORION F selective electrode. ANOVA test, t-test. The mean F values for groups M and S were found to be 0.031 and 0.07 ppm, respectively. Fluoride content of milk-based formulae was significantly lesser (P < 0.001) than soy-based formulae. Daily fluoride intake through the tested formulae was in the range of 0.013 mg and 0.105 mg when calculated following the manufacturer's preparation guidelines. Infant formulae alone were unlikely to be a risk factor for dental fluorosis, but when reconstituted with optimally fluoridated water, they can be a risk factor for the development of dental fluorosis.

Dental fluorosis and associated risk factors among secondary school students in Zing community, North-Eastern Nigeria

Fluorosis affects both children’s oral health and quality of life because even the mildest form of tooth discoloration is considered cosmetically unacceptable and is a cause of psychological concern for those affected. This study aims to assess the prevalence of dental fluorosis and determine its associated risk factors among adolescents in the Zing community. This study is a quantitative crosssectional survey. The study participants were 300 children residing in Zing community and studying in one of the secondary schools selected for this study using a systematic random sampling technique. A questionnaire was designed and pretested to record information about demographic characteristics and risk factors for dental fluorosis. The children were also asked about their source of water consumption and their main source of drinking water recorded. The Dean Fluorosis Index (1934) was used to determine the grade of the severity of dental fluorosis. A Chi-square analysis test was used to test for possible associations. The prevalence of dental fluorosis was calculated as 52.0% and it varied significantly with age. A severe form of dental fluorosis (21.7%) was the most common grade of severity of dental fluorosis. Mild dental fluorosis had the lowest prevalence of 6.0%. The correlation between the occurrence of dental fluorosis and the duration of residence was found to be highly statistically significant (p≤0.001). The prevalence of dental caries in this study was 12.7%. No correlation was found between dental fluorosis and caries status. The prevalence of dental fluorosis was significantly high among the secondary school students of the Zing community in Taraba State. There is thus a need for health education and community awareness for preventing fluorosis and for early intervention to reduce the consequences on dental and periodontal health status.

Use of Fluoridated Toothpaste in Children - A Review

Studies have shown that early fluoride use or “low but excessive” fluoride intake during the development of teeth is a risk factor for dental fluorosis in both fluoridated and non-fluoridated environments. Fluorosis affects children under the age of six who have developing, unerupted, and erupted permanent teeth. This changes the appearance of the teeth and leads to mental disturbance. This review enumerates fluoride, fluoridated toothpastes and its utilization in children.

Dental fluorosis and associated risk factors in early adolescents in India.

Background Dental fluorosis has a negative impact on the facial esthetics of adolescents and is a worldwide oral health concern. Objective To assess the prevalence and associated risk factors for dental fluorosis in early adolescents in India. Methods This was a cross-sectional study carried out on 800 adolescent school children selected from the Jhabua and Dhar districts of Madhya Pradesh, India. The children were in the of 12-15-year age group. A total of eight schools from both Jhabua and Dhar districts were included in the study. A self-administered questionnaire collected information on demographic characteristics, oral hygiene practices and various risk factors for dental fluorosis. Water samples were collected from each zone and sent to a laboratory for water fluoride estimation. Dental fluorosis was assessed using the Dean index. Chi-squared (χ2) and logistic regression analysis were performed. Results The overall prevalence of dental fluorosis was found to be 40.5% in early adolescents. The prevalence of dental fluorosis was found to be 45% in the Jhabua district and 36% in the Dhar district. The water fluoride content was found to be the strongest predictor for dental fluorosis followed by the method of water storage. Conclusion Dental fluorosis affects a large number of adolescents in both the Jhabua and Dhar districts of Madhya Pradesh. Effective policies focusing on oral health education and prevention of dental fluorosis need to be drafted.

The effect of elemental content on the risk of dental fluorosis and the exposure of the environment and population to fluoride produced by coal-burning

Endemic fluorosis is a geochemical disease that affects thousands of people. Growing evidence from domestic and foreign studies indicate that fluorosis is associated with an abnormal level of the elements (such as F, Ca, Fe, Mg, Cu, Zn, P) in the environment and a population exposed to fluoride. To study the effect of the elemental content on the risk of dental fluorosis, the content of 25 elements in the environment produced by coal-burning and a population exposed to fluoride was determined. The results show that an abnormal level of various elements (including F, Al, Se, Zn, Cu, Fe, Mo, Mn, B, V, Ca, Mg, and P) in the population exposed to fluoride, which is related to the increasing or decreasing of the corresponding elements in the environment. Subsequent univariate and multivariate regression analyses show that high levels of F, Al, As, Pb and Cr were a risk factor for dental fluorosis, but not Se, Zn, Cu, B, Ca and P which were a protective factor for dental fluorosis. This study can provide a scientific basis for a further understanding of the causes of health damage caused by fluoride and the improvement of targeted prevention strategies.

ASSESSMENT OF DENTAL FLUOROSIS IN CHILDREN OF JAIPUR DISTRICT, RAJASTHAN, INDIA

Objective: The objective of the present study was carried out to explore the potential association between fluoride concentration in drinking water and severity of dental fluorosis (DF) in the children.Methods: The study of dental fluorosis (DF) in the children (6-14 years old) was conducted in the two blocks (a) Jamwaramgarh block ;Heerawala, Palera ,Nayabas, Saipur and Birasana, (b) Amber block; Jugalpura, Chitanukalan, Sunder ka bas, Peelwa and Sirsali of Jaipur district, Rajasthan, India of the study villages. Total 150, children were surveyed. The role of fluoride (F) levels in drinking water in the etiology of dental fluorosis (DF) and the cases of dental fluorosis (DF) in both dentitions and teeth were also assessed using DEAN’S classification. The fluoride (F) concentration in source of drinking water was estimated by fluoride (F) ion specific electrode (Thermo Scientific Orion Star A329, USA).Results: The F concentration in (Tube well and Hand pump) water ranges from 0.7 to 15.0 parts per million (ppm) in Jamwaramgarh block and 1.40 to 5. 10 parts per million (ppm) in Amber block. Prevalence of dental fluorosis (DF) 27 (36%) in Jamwaramgar block and 26 (34.66%) in Amber block out of 75 children were examined in each block. Significantly increase in levels of F in drinking water is positively correlated with dental fluorosis.Conclusion: This study finding has shown the relation of dental fluorosis (DF) to high fluoride (F) levels in drinking water sources. A higher fluoride (F) levels in source of drinking water is a major risk factor for dental fluorosis. In view of the severity of the problem the intake of calcium rich foods and defluoridation techniques may help reducing risk of dental fluorosis (DF) in the children.

Factors associated with dental fluorosis in school children in southern Brazil: a cross-sectional study.

This cross-sectional study assessed risk factors for dental fluorosis (DF) among 8- to 12-year-old children in southern Brazil. Children attending 20 schools were randomly selected (n=1,196). They were interviewed and their parents answered a questionnaire that was sent home. Prevalence of DF was 8.53% (modified Dean's criteria), and the prevalence of severe DF was 0.17%. The results of multiple logistic regression analyses indicated that DF was associated with a higher frequency of tooth brushing and with initial use of fluoride toothpaste at the emergence of the first tooth. DF does not constitute a public health problem in southern Brazil.

Fluoridated toothpaste: usage and ingestion of fluoride by 4‐ to 6‐yr‐old children in England

Fluoridated toothpaste is effective for dental caries control, yet may be a risk factor for dental fluorosis. This study aimed to quantify fluoride ingestion from toothpaste by children and to investigate the effects of age, gender, and social class on the amount of fluoride ingested per toothbrushing session. Sixty-one children, 4-6 yr of age, were recruited: 38 were from low socio-economic (LSE) areas of Newcastle, UK, and 23 were from high socio-economic (HSE) areas of Newcastle, UK. All expectorated saliva, rinse water (if used), and residual toothpaste were collected after brushing at home and were analysed for fluoride. Of the children, 74% and 69% from HSE and LSE areas, respectively, claimed that they brushed twice per day. The mean (SD) weight of toothpaste dispensed was 0.67 (0.36) g. The mean (SD) amount of fluoride ingested per toothbrushing session and per day was 17.0 (14.7) and 29.3 (32.8) μg kg(-1) of body weight, respectively. Daily fluoride intake per kilogram of body weight did not differ significantly between children from LSE and HSE areas. Fluoride intake per toothbrushing session was significantly influenced by weight of toothpaste, its fluoride concentration, and the child's age. Whilst the average amount of toothpaste used per toothbrushing session was more than twice the recommended amount (of 0.25 g), only one child had a daily fluoride intake that exceeded the tolerable upper intake level of 0.1 mg kg(-1) of body weight for this age group.

Fluoride content of Ready‐to‐Feed (RTF) infant food and drinks in the UK

The level of Fluoride exposure needed to cause dental fluorosis is not known precisely. An awareness of total F intake from all sources, especially during the critical stages of dental development during infancy and early childhood, is important in preventing the development of dental fluorosis. The aim of the study was to measure F content of ready-to-feed (RTF) infant drinks and foods in the UK. In total, 122 infant foods were analysed for F concentrations, in triplicate, indirectly by an acid diffusion method and 25 infant drinks analysed directly using an F-ion-selective electrode after addition of TISABIII. The median (range) F concentration was 0.110 (0.030-0.221) μg/g for breakfast cereals, 0.112 (0.040-1.200) μg/g for savoury meals, 0.056 (0.030-0.379) μg/g for desserts, 0.044 (0.020-0.191) μg/g for fruits, 0.196 (0.040-0.397) μg/g for baked goods, 0.069 (0.050-0.148) μg/ml for juices, 0.016 (0.009-0.030) μg/ml for milks and 0.041 (0.022-0.069) μg/ml for waters. The median (range) F concentration of all RTF infant foods and drinks by recommended age of consumption was 0.029 (0.010-0.245), 0.088 (0.020-0.500), 0.108 (0.100-0.510) and 0.108 (0.060-1.200) μg/g for infants from birth, 4+ month, 6+ month and 10+ month, respectively. The results suggest that the F concentrations of UK-marketed RTF infant foods, drinks and formula milk are not sufficiently high to be a risk factor for dental fluorosis, if consumption is within the limits recommended for infants and young children.

Analysis of protection or risk factors for dental fluorosis in 6 to 8 year-old children in Fortaleza, Brazil

To investigate protection or risk factors for dental fluorosis in permanent teeth of 6 to 8 year-old children in a neighborhood of Fortaleza, Brazil. This case-control study included 57 controls and 67 children with fluorosis affecting superior and inferior incisors teeth as determined by the Dean classification criteria. Presence of fluorosis was considered as the dependent variable. Data concerning independent variables were obtained through interviews with the parents. Fisher's exact test was used to determine associations between fluorosis and the independent variables. Odds ratios (OR) were calculated to investigate associations and likelihood of fluorosis in the case group, with 95% significance level. Fluorosis was significantly associated with type of housing (owned, rented or squatted), but not with the source of drinking water or use of fluoridated toothpaste and fluoride supplements. Univariate analysis showed that the risk of fluorosis was higher in children who began drinking powdered milk mixed with water before 2 years of age (OR = 4.53; IC95%: 1.07-26.74) and in those who did not breastfeed (OR = 6.66; IC95%: 1.61-38.62). In the multivariate analysis, only breastfeeding was associated with fluorosis (4.54; IC95%: 1.21-16.66). Breastfeeding was a protection factor against fluorosis. More specific categorization criteria must be established to investigate relationships between fluorosis and socioeconomic class.

Use of the Fluorosis Risk Index in a Cohort Study: The Iowa Fluoride Study

Several studies have used the Fluorosis Risk Index (FRI) to assess risk factors for dental fluorosis. This study reports fluorosis prevalence estimates in a birth cohort using the FRI in different ways. Subjects (n=443) were participants in the Iowa Fluoride Study, a birth cohort study of fluoride exposures and intake, fluorosis, and caries. Early-erupting permanent teeth were assessed for fluorosis using the FRI at approximately age 9. Fluorosis prevalence rates were calculated separately for specific teeth and different combinations of teeth, with varied FRI zones included and using different thresholds. Mean numbers of teeth with fluorosis were calculated. Tooth-specific fluorosis prevalence varied, with maxillary central incisor fluorosis most prevalent and mandibular incisors least affected. Considering three zones of each tooth (cervical zones excluded), 40.6% overall had at least one tooth with mild or more involved fluorosis, 30.2% were questionable fluorosis, and 29.1% had no fluorosis. When only FRI zone I areas were considered, the corresponding percentages were 33.2%, 29.3%, and 37.5%, respectively. When different combinations of teeth were used to define fluorosis cases, the prevalences estimated using three zones were generally 1 to 9 percentage points higher than those estimated from FRI zone 1 only. Most fluorosis was mild, with only 7 individuals (1.6%) having FRI severe fluorosis. The FRI has advantages for use in analytical epidemiologic studies of dental fluorosis. However, the population prevalence estimates vary, depending on the index and case definition used. Therefore, it is recommended that consideration be given to concurrent use of another index (i.e., TSIF, TF, Dean's) if prevalence estimates are an important study outcome.

Fluoride content of bottled waters available in Northern Greece

The aim of this study was to evaluate the fluoride content of bottled drinking waters commercially available in northern Greece and to report on the accuracy of the labelling of fluoride concentration. Twenty-two randomly selected commercial brands of bottled water were obtained from three supermarkets in Thessaloniki, Greece. Three bottles of each brand were purchased. Following calibration, six tests were conducted on each bottle using a combination fluoride-ion selective electrode (Orion, 96-09-00, MA, USA). The average reading for each brand was estimated and also compared with the fluoride content printed on the label. The mean (+/- SD) fluoride content of the bottled water samples was 0.35 (+/- 1.00) mg F/L with a range from 0.05 to 4.8 mg F/L. Only 18% (N = 4) of brands tested mention the fluoride concentration on the label, and 90% (N = 22) had a tested fluoride between 0.05 and 0.21 mg F/L. Of the remaining two brands, one was found to contain 0.3 mg F/L without having the fluoride concentration indicated on the label, and the other was labelled at 6 mg F/L, whereas the concentration was estimated as 4.8 mg F/L. The use of bottled water may be a significant source of systemic fluoride and therefore be considered as a risk factor for dental fluorosis in young children. This article shows that bottled drinking waters contain differing concentrations of fluoride. The manufacturers' labelling of fluoride concentrations may be inaccurate. When prescribing fluoride supplements, dentists should be aware of the fluoride content of bottled waters used by paediatric patients, especially brands with a concentration higher than 0.3 mg F/L. In view of the wide variation of fluoride concentration in the tested bottled waters, regulatory guidelines for controlling concentration in order to prevent dental fluorosis are recommended.

Greater tooth-brushing frequency, fluoride supplement use, and tap water fluoride concentrations above 0.7 mg/L are risk factors for dental fluorosis

Bottenberg P, Declerck D, Ghidey W, Bogaerts K, Vanobbergen J, Martens L. Prevalence and determinants of enamel fluorosis in Flemish schoolchildren. Caries Res 2004;38(1):20-8. 2b What are the relationships between exposures to various fluoride sources and dental fluorosis? Industry: Lever-Elida, Brussels Cohort study (or could be considered Prevalence/Cross Sectional Study)

Source of drinking water and other risk factors for dental fluorosis in Sri Lanka

This study was done to describe the association between source of drinking water and other potential risk factors with dental fluorosis. Prevalence of dental fluorosis among 518 14-year-old students in the south of Sri Lanka was 43.2%. The drinking water sources of the students were described and fluoride samples were taken. There was a strong association between water fluoride level and prevalence of fluorosis. Tea drinking before 7 years of age was also an independent risk factor in a multivariate analysis. Having been fed with formula bottle milk as an infant seemed to increase the risk although the effect was not statistically significant. No clear effects could be found for using fluoridated toothpaste, occupation of the father, and socio-economic status. Drinking water obtained from surface water sources had lower fluoride levels (median 0.22 mg l−1) than water from deep tube wells (median 0.80 mg l−1). Most families used shallow dug wells and these had a median fluoride value of 0.48 mg l−1 but with a wide range from 0.09 to 5.90 mg l−1. Shallow wells located close to irrigation canals or other surface water had lower fluoride values than wells located further away. Fluoride levels have to be taken into account when planning drinking water projects. From the point of view of prevention of dental fluorosis, drinking water from surface sources or from shallow wells located close to surface water would be preferable.

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

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

Severe dental fluorosis in a Tanzanian population consuming water with negligible fluoride concentration.

To identify risk factors for dental fluorosis that cannot be explained by drinking water fluoride concentration alone. Two hundred eighty-four Tanzanian children ages 9 to 19 (mean 14.0+/-SD 1.69), who were lifetime residents at differing altitudes (Chanika, 100 m; Rundugai, 840 m; and Kibosho, 1,463 m; Sites 1, 2, and 3 respectively) were examined for dental fluorosis and caries. They were interviewed about their food habits, environmental characteristics and use of a fluoride-containing food tenderizer known locally as magadi. Meal, urine, water and magadi samples supplied by the participants were analyzed for fluoride content. Urine samples were also analyzed for creatinine concentration. Four magadi samples from Sites 1 and 3 were analyzed for complete element composition. Of the 13 water samples from Site 2, 10 contained > or =4 mg/L F, ranging from 1.26 to 12.36 mg/L with a mean+/-SD of 5.72+/-4.71 mg/L. Sites 1 and 3 had negligible water fluoride of 0.05+/-0.05 and 0.18+/-0.32 mg/L respectively. Mean TFI fluorosis scores (range 0-9) for Site 2 were high: 4.44+/-1.68. In Sites 1 and 3, which both had negligible water fluoride, fluorosis scores varied dramatically: Site 1 mean maximum TFI was 0.01+/-0.07 and Site 3 TFI was 4.39+/-1.52. Mean DMFS was 1.39+/-2.45, 0.15+/-0.73 and 0.19+/-0.61 at Sites 1, 2, and 3, respectively. There were no restorations present. Urinary fluoride values were 0.52+/-0.70, 4.34+/-7.62, and 1.43+/-1.80 mg/L F at Sites 1, 2, and 3, respectively. Mean urinary fluoride values at Site 3 were within the normal urinary fluoride reference value range in spite of pervasive severe pitting fluorosis. Meal and magadi analyses revealed widely varied fluoride concentrations. Concentrations ranged from 0.01 to 22.04 mg/L F for meals and from 189 to 83211 mg/L F for magadi. Complete element analysis revealed the presence of aluminum, iron, magnesium, manganese, strontium and titanium in four magadi samples. There were much higher concentrations of these elements in samples from Site 3, which was at the highest altitude and had severe enamel disturbances in spite of negligible water fluoride concentration. An analysis of covariance model supported the research hypothesis that the three communities differed significantly in mean fluorosis scores (P<0.0001). Controlling for urinary fluoride concentration and urinary fluoride:urinary creatinine ratio, location appeared to significantly affect fluorosis severity. Urinary fluoride:urinary creatinine ratio had a stronger correlation than urinary fluoride concentration with mean TFI fluorosis scores (r=0.43 vs r= 0.25). The severity of enamel disturbances at Site 3 (1463 m) was not consistent with the low fluoride concentration in drinking water, and was more severe than would be expected from the subjects' normal urinary fluoride values. Location, fluoride in magadi, other elements found in magadi, and malnutrition are variables which may be contributing to the severity of dental enamel disturbances occurring in Site 3. Altitude was a variable which differentiated the locations.

Fluoride content of infant formulae in Australia

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 micrograms F/g and for soy-based formulae from 1.08 to 2.86 micrograms 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 percent 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.