Plasma Fluoride Levels Research Articles

Reconstructing temporal variation of fluoride uptake in eastern grey kangaroos (Macropus giganteus) from a high-fluoride area by analysis of fluoride distribution in dentine

Trace element profiling in the incrementally formed dentine of mammalian teeth can be applied to reconstruct temporal variation of incorporation of these elements into the tissue. Using an electron microprobe, this study analysed fluoride distribution in dentine of first and third mandibular molars of free-ranging eastern grey kangaroos inhabiting a high-fluoride area, to assess temporal variation in fluoride uptake of the animals. Fluoride content in the early-formed dentine of first molars was significantly lower than in the late-formed dentine of these teeth, and was also lower than in both, the early and the late-formed dentine of third molars. As early dentine formation in M1 takes place prior to weaning, this finding indicates a lower dentinal fluoride uptake during the pre-weaning compared to the post-weaning period. This is hypothetically attributed to the action of a partial barrier to fluoride transfer from blood to milk in lactating females and a low bioavailability of fluoride ingested together with milk. Another factor contributing to lower plasma fluoride levels in juveniles compared to adults is the rapid clearance of fluoride from blood plasma in the former due to their intense skeletal growth. The combined action of these mechanisms is considered to explain why in kangaroos from high-fluoride areas, the (early-formed) first molars are not affected by dental fluorosis while the (later-formed) third and fourth molars regularly exhibit marked to severe fluorotic lesions.

Effect of Moringa oleifera on hematological parameters of calves reared in industrial fluorotic area.

Aim:The present study was undertaken to evaluate the ameliorative potential of dried Moringa oleifera fruit powder in fluorosis affected calves reared around the vicinity of aluminium smelter plant.Materials and Methods:Total 107 calves were screened on the basis of clinical signs and higher plasma fluoride (more than 0.2 ppm) level for evidence of fluorosis. Out of that, 90 samples found positive and from them 18 calves of 6-12 months age group were selected and divided equally into three groups named as Group II, III, and IV. Group II remained as disease control group whereas Group III calves were supplemented with dried M. oleifera fruit powder of 25 g/calve for 60 days. Group IV calves were supplemented with calcium carbonate at 100 mg/kg body weight and boric acid at 10 mg/kg for the same experimental period. Group I consisted of six numbers of healthy calves taken from the non-fluorotic zone, i.e. Bhubaneswar. Plasma fluoride level, hemoglobin (Hb), packed cell volume (PCV), total leukocyte count (TLC), differential count (DC), total erythrocyte count, mean corpuscular volume (MCV), mean corpuscular Hb (MCH), and MCH concentration (MCHC) were estimated on day 0, 30, and 60 of the experiment.Results:Supplementation of dried M. oleifera fruit powder to fluorosis affected calves resulted in significant reduction in plasma fluoride level and increase in Hb%, PCV, TLC and altered DC. Similar results were also recorded in calcium+boron group, except PCV and Hb. No significant changes were observed in MCV, MCH, and MCHC values.Conclusion:The present study concluded that supplementation of dried M. oleifera fruit powder daily for 60 days has shown protection against chronic fluoride toxicity in calves.

Plasma fluoride level as a predictor of voriconazole-induced periostitis in patients with skeletal pain.

Voriconazole is a triazole antifungal medication used for prophylaxis or to treat invasive fungal infections. Inflammation of the periosteum resulting in skeletal pain, known as periostitis, is a reported side effect of long-term voriconazole therapy. The trifluorinated molecular structure of voriconazole suggests a possible link between excess fluoride and periostitis, as elevated blood fluoride has been reported among patients with periostitis who received voriconazole. Two hundred sixty-four patients from Michigan were impacted by the multistate outbreak of fungal infections as a result of contaminated methylprednisolone injections. A retrospective study was conducted among 195 patients who received voriconazole therapy at St Joseph Mercy Hospital during this outbreak. Twenty-eight patients who received both bone scan and plasma fluoride measurements for skeletal pain were included in the statistical analyses. Increased tracer uptake on bone scan was considered positive for periostitis. The primary outcome measure was the correlation between plasma fluoride and bone scan results. Blood fluoride (P < .001), alkaline phosphatase (P = .020), daily voriconazole dose (P < .001), and cumulative voriconazole dose (P = .027) were significantly elevated in patients who had periostitis compared with those who did not. Discontinuation or dose reduction of voriconazole resulted in improvement of pain in 89% of patients. High plasma fluoride levels coupled with skeletal pain among patients who are on long-term voriconazole therapy is highly suggestive of periostitis. Initial measurement of fluoride may be considered when bone scan is not readily available. Early detection should be sought, as discontinuation of voriconazole is effective at reversing the disease.

Dental fluorosis and periodontium: A game of shadows?

Dental fluorosis is a condition which is said to be present when the morphologic features of a tooth are altered clinically, in the form of discoloration or anatomic malformation which is attributed to the developmental changes induced by excess fluoride levels in plasma at the time of tooth formation. In India, an estimated 60 million people are at risk and 6 million people are disabled due to fluorosis. Lack of understanding into the effects of fluorosis on periodontium has left a blind spot in the vision of management of periodontitis in such patient groups. This article suggests the important connection these two conditions can have and emphasize research in this study field.

Physical exercise ameliorates the toxic effect of fluoride on the insulin–glucose system

Daily intake of water with fluoride concentrations >1.5 mg/l produces insulin resistance (IR). On the other hand, physical activity increases insulin sensitivity in the muscle. Therefore, the aim of this study was to evaluate the effect of physical activity on IR in rats treated with sodium fluoride (NaF) in drinking water. Sprague-Dawley rats were divided into three groups (n=10/group): Control (drinking water without NaF), NaF (drinking water with NaF 15 mg/l for 30 days), and Exercise (daily running on a treadmill for 60 min at 2.25 m/min and drinking water with NaF 15 mg/l for 30 days). IR was evaluated with the homeostasis model assessment-IR (HOMA-IR) index using fasting plasma levels of glucose and insulin. IR increased in rats treated with 15 mg/l NaF in drinking water. A decrease in IR was observed in rats that performed physical activity and drank water with 15 mg/l NaF; the Exercise group also showed an increase in the amounts of bone fluoride. The variation in the HOMA-IR values could be the consequence of variation in the sensitivity of tissues to insulin or decrease in plasma fluoride levels due to bone fluoride intake. These findings indicate that the performance of daily physical activity could reduce the negative effects of the chronic ingestion of NaF on glucose homeostasis.

Fluoride Levels of Mothers’ Breast Milk in Egypt

Introduction: Fluoride exists naturally in water sources and is derived from fluorine. It is well known that fluoride helps, prevent and even reverse the early stages of tooth decay. Aim: The aim of the present study was to determine the fluoride levels in plasma and breast milk of lactating mothers in Egypt (Cairo and Giza Governorate). Material and Methods: Two hundred healthy lactating mothers aged between 20-40 years old were asked to give plasma and milk samples voluntary. Breast milk samples were directly refrigerated until measurements. The fluoride concentrations of plasma, milk and drinking tap water were assessed using an ion-selective fluoride electrode combined with an ion analyzer. Results: The fluoride levels of plasma, breast milk and drinking tap water samples were 0.0207±0.012,0.0111±0.0044 ppm, and 0.482±0.117 ppm, respectively. A significant direct correlation between fluoride content in breast milk and drinking tap water was found (r=0.858, p< 0.01).

Fluoride Levels of Mothers’ Breast Milk in Egypt

Introduction: Fluoride exists naturally in water sources and is derived from fluorine. It is well known that fluoride helps, prevent and even reverse the early stages of tooth decay. Aim: The aim of the present study was to determine the fluoride levels in plasma and breast milk of lactating mothers in Egypt (Cairo and Giza Governorate). Material and Methods: Two hundred healthy lactating mothers aged between 20-40 years old were asked to give plasma and milk samples voluntary. Breast milk samples were directly refrigerated until measurements. The fluoride concentrations of plasma, milk and drinking tap water were assessed using an ion-selective fluoride electrode combined with an ion analyzer. Results: The fluoride levels of plasma, breast milk and drinking tap water samples were 0.0207±0.012,0.0111±0.0044 ppm, and 0.482±0.117 ppm, respectively. A significant direct correlation between fluoride content in breast milk and drinking tap water was found (r=0.858, p< 0.01).

Fluoride Excess and Periostitis in Transplant Patients Receiving Long-Term Voriconazole Therapy

We describe a heart transplant patient with painful periostitis and exostoses who was receiving long-term therapy with voriconazole, which is a fluoride-containing medication. Elevated plasma and bone fluoride levels were identified. Discontinuation of voriconazole therapy led to improvement in pain and reduced fluoride and alkaline phosphatase levels. To determine whether voriconazole is a cause of fluoride excess, we measured plasma fluoride levels in 10 adult post-transplant patients who had received voriconazole for at least 6 months and 10 post-transplant patients who did not receive voriconazole. To assess the effect of renal insufficiency on fluoride levels in subjects receiving voriconazole, half were recruited on the basis of a serum creatinine level of ≥1.4 mg/dL on their most recent measurement, whereas the other 5 subjects receiving voriconazole had serum creatinine levels <1.4 mg/dL. All control subjects had serum creatinine levels of ≥1.4 mg/dL. Patients were excluded from the study if they received a fluorinated pharmaceutical other than voriconazole. All subjects who received voriconazole had elevated plasma fluoride levels, and no subjects in the control group had elevated levels (14.32 μmol/L ± 6.41 vs 2.54 ± 0.67 μmol/L; P<.001). Renal function was not predictive of fluoride levels. Plasma fluoride levels remained significantly higher in the voriconazole group after adjusting for calcineurin inhibitor levels and doses. Half of the voriconazole group subjects had evidence of periostitis, including exostoses in 2 patients. Discontinuation of voriconazole therapy in patients with periostitis resulted in improvement of pain and a reduction in alkaline phosphatase and fluoride levels. Voriconazole is associated with painful periostitis, exostoses, and fluoride excess in post-transplant patients with long-term voriconazole use.

Single and multiple daily dose toxicokinetics of fluoride after oral administration of sodium fluoride along with aluminum sulfate in goats

Our previous study suggested that toxicokinetic parameters of fluoride were significantly changed on the 30th day as compared with 1st day, after repeated oral administration of sodium fluoride alone for 30 days in goats. The purpose of this study was to investigate whether aluminum sulfate has ameliorative effect on the toxicokinetics of fluoride. For this, sodium fluoride (20 mg kg−1 b. wt.) along with aluminum sulfate (150 mg kg−1 b. wt.) was administered in goats for 30 days to investigate its effect on toxicokinetics of fluoride on days 1 and 30. The fluoride levels against time were adequately described by one compartment open model. The peak plasma level of fluoride was observed at 2 h. The toxicokinetics data revealed a nonsignificant decrease in β (elimination rate constant) and C max (the maximum plasma concentration) and increase in t 1/2 K a (absorption half-lives), t 1/2 β (elimination half-lives), area under the plasma (AUC) concentration versus time curve and mean residence time (MRT) was observed for the last dose from their respective first dose values. On the basis of changes in the toxicokinetic parameters, it was concluded that repeated oral administration has cumulative effect on plasma fluoride level and concurrent oral administration of aluminum sulfate has ameliorative action on the toxicokinetics of fluoride in goats.

Single and multiple daily dose toxicokinetics of fluoride after oral administration of sodium fluoride in goats

The toxicokinetics of fluoride was investigated in healthy cross breed goats after single and repeated oral administration of sodium fluoride (20 mg kg−1 b.wt.) for 30 days. Serial blood samples at various predetermined time intervals were collected for plasma separation on days 1 and 30 of administration. The plasma fluoride levels were estimated by using ion selective electrode of Orion Fluoride Analyzer using 96-09 combination fluoride electrode. The plasma levels of fluoride against time were adequately described by one compartment open model. The plasma peak level of fluoride was observed for 2 h. The toxicokinetic data revealed that for last dose, the mean values of β and ClB were significantly (p < 0.01) lower, whereas, the values of t 1/2β, AUC and MRT were significantly (p < 0.05) higher from their respective first dose values. The time concentration profile of plasma fluoride levels and toxicokinetics data revealed that repeated oral administration of fluoride has a cumulative effect in the body of the goats.

Kinetics of fluoride removal from plasma and bone of rats after chronic intake of fluoride

This study evaluated the kinetics of fluoride in plasma, femur surface and the whole femur of rats, after chronic exposure to different water fluoride levels was interrupted. Four groups of Wistar rats received drinking water containing 0, 5, 15 or 50 microg F/ml for 60 days (n = 50/group). The animals were euthanized immediately after exposure to fluoride or after 7, 30, 90 or 180 days (n = 10/subgroup). Plasma and femurs were collected. Fluoride on the femur surface, whole femur and plasma was analyzed with an electrode. Data were analyzed using ANOVA and Tukey's test (p< 0.05). The increase in plasma fluoride levels was significant only for the 50 microg F/ml group at 0 and 7 days. Regarding bone surface and whole bone, for most groups, significant increases in fluoride concentrations were observed with the increase in water fluoride concentrations at each time of euthanasia. For fluoride doses up to 15 microg F/ml, femur surface fluoride levels were reestablished 180 days after the exposure was discontinued, which was not valid for whole femur or for higher fluoride doses. We found a different kinetics of fluoride in plasma, femur surface and the whole femur of rats after chronic exposure to fluoride is interrupted.

Fluoride effects on ectopic bone formation in young and old rats

This study evaluated the effect of fluoride on bone fluoride levels and on ectopic bone formation in young and old rats. Eighty male Wistar rats were assigned to four groups (n = 20/g), which differed according to the fluoride concentration in their drinking water (0, 5, 15 and 50 mg/l). When half of the rats were 90 days old, demineralized bone matrix (DBM) was implanted. The other rats received DBM implants when they were 365 days old. The animals were killed 28 days after. Fluoride in the femur surface, whole femur and plasma was analyzed with an electrode. The implants were analyzed histomorphometrically. Data were tested for statistically significant differences by ANOVA, Tukey's test, t-test and linear regression (p < 0.05). Increases in plasma, femur surface and whole femur fluoride concentrations were observed as water fluoride levels increased. There was also a trend for increase in plasma and femur fluoride concentrations as age increased. Significant positive correlations were found between plasma and femur surface, plasma and femur and femur surface and femur fluoride concentrations. The morphometric analyses indicated an increase in bone formation for younger rats that received 5 mg/l of fluoride in the drinking water. However, this was not statistically significant. The younger rats that received 50 mg/l of fluoride showed impairment in bone formation. Bone formation was not significantly affected among the older rats. The results suggest that lower doses of fluoride in the drinking water, which slightly increase plasma fluoride levels, may have an anabolic effect on bone formation in younger rats.

Effect of Long-term Fluoride Exposure on Lipid Peroxidation and Histology of Testes in First- and Second-generation Rats

This experiment was designed to investigate the histological and lipid peroxidation effects of chronic fluorosis on testes tissues of first- and second-generation rats. Sixteen virgin female Wistar rats were mated with eight males (2:1) for approximately 12 h to obtain first-generation rats. Pregnant rats were divided into two groups: controls and fluoride-given group, each of which containing five rats. Pregnant rats in the fluoride-given group were exposed to a total dose of 30 mg/l sodium fluoride (NaF) in commercial drinking water containing 0.07 mg/l of NaF throughout the gestation and lactation periods. After the lactation period, the young animals (first generation, F1) were exposed to the same dose of NaF in drinking water for 4 months. At the end of the 4 months of experimental period, nine randomly chosen male rats (F1) were killed and testes tissues were taken for histopathological and biochemical analysis. The remaining eight female rats were mated with four males (2:1) for approximately 12 h to obtain second-generation rats. Six female were identified as pregnant and treated with similarly throughout the gestation and the lactation periods. After the lactation period, the young male animals (second generation, F2) were also treated in the same way for 4 months. At the end of the 4 months of experimental period, nine randomly chosen male rats (F2) were killed and testes tissues were collected for histopathological and biochemical analysis. The rats in the control group were applied the same procedure without NaF administration. In biochemical analysis of the fluoride given F1 and F2 rats, it has been found that plasma fluoride levels and testes thiobarbituric acid reactive substance levels were significantly increased when compared with the control group. In F1 and F2 rats, similar histopathological changes were observed. In both groups, spermatogenesis was severely reduced. Spermatogonia and primary spermatocytes were normal, however, there was a widespread degeneration in other spermatogenic cell lines of the seminiferous epithelium. The histological structures of the Sertoli and interstitial Leydig cells were normally observed. It is concluded that chronic fluorosis exposure leads to a remarkable destruction in testes tissues of F1 and F2 rats via lipid peroxidation.

Fluoride Levels of Human Plasma and Breast Milk

The aim of this study was to determine the fluoride levels in breast milk and plasma of lactating mothers who regularly consumed drinking water with low levels of fluoride. One hundred twenty five healthy mothers aged between 20-30 years old who had given birth within 5-7 days were included in the study. Besides being otherwise healthy, the primary selection criteria stipulated the absence of fluoride supplement consumption one month before delivery. Approximately 5 ml breast milk and 5 ml blood samples were obtained from each participating mother at a hospital setting, where the mothers were scheduled for a regular hospital diet. The blood samples were centrifuged in fluoride-free heparinized polyethylene tubes and stored at -18 degrees C until measurements were made. Breast milk samples were directly refrigerated as with blood samples until measurements. The fluoride concentrations of milk and blood samples were assessed using an ion-selective fluoride electrode combined with an ion analyzer. The fluoride levels of the plasma and breast milk samples were measured as 0.017+/-0.011 ppm and 0.006+/-0.002 ppm, respectively. The fluoride concentration of plasma was significantly higher than that of breast milk (P<.01). Correlation analysis revealed a significant relation between the groups (P<.01). A limited level of fluoride transmission from plasma to breast milk was detected. Nevertheless, a significant correlation between the fluoride concentrations of breast milk and plasma was evident.

Variations in concentration of fluoride in blood plasma of pregnant women and their possible consequences for amelogenesis in a fetus

The aim of the study was to assess the fluoride exposure of pregnant women living in Poznan (Poland) by examination of fluoride levels in blood plasma. The subjects of the study were 31 pregnant women aged 22–34 years in the course of regular pregnancy. Data concerning the sources of fluoride exposure such as diet, oral hygiene measures and topical application of fluoride procedures, were collected from each individual with a questionnaire. Samples of blood plasma were drawn in the 28th, 33rd week of pregnancy and during delivery. The analysis evaluating the fluoride concentration in the samples was carried out with the use of fluoride electrode ORION (model 96-09). The data were statistically analyzed using the program Statistica for Windows. Mean value of fluoride concentration in the samples of blood plasma from the 28th week of pregnancy was lower than the mean concentration detected in the 33rd week of pregnancy (3.29 and 3.73 μmol/l, respectively). These values suggest that apart from drinking water, there were other important sources of fluoride in the examined sample. The results indicate that a reliable assessment of fluoride exposure in a given population cannot be based solely on the concentration of fluoride in drinking water. Relatively high levels of fluoride in blood plasma of examined women suggest that there is no need for fluoride supplementation in this group of patients.

Subchronic Toxicity of a Fluoroalkylethanol Mixture in Rats

The objective of this study was to evaluate the subchronic toxicity of a commercial fluoroalkylethanol mixture, which is an intermediate in the production of fluoroorganic compounds that are used as protectants and surfactants. The test substance was administered daily by gavage to Sprague–Dawley rats as a suspension in aqueous methylcellulose. The dosages were 0, 25, 100, or 250 mg kg− 1 day− 1. A 1- and 3-month recovery period was included to evaluate the reversibility of toxic effects. No test substance–related mortality or neurotoxicity occurred. Body weights and/or nutritional parameters were significantly reduced at 100 and 250 mg kg− 1 day− 1, and these effects were reversible. Broken and absent teeth were observed in rats dosed with 250 mg kg− 1 day− 1, and microscopic tooth lesions (ameloblast degeneration/disorganization) occurred at 100 and 250 mg kg− 1 day− 1 and persisted with decreased severity throughout recovery. Decreased red cell mass parameters occurred at 90 days in the 250 mg kg− 1 day− 1 group, but red cell counts were normal thereafter during recovery. A persistent elevation of liver weights was seen in groups given ≥ 100 mg kg− 1 day− 1. The increased weights correlated with microscopic hepatocellular hypertrophy only in males and females administered 250 mg kg− 1 day− 1. Hepatic β-oxidation was increased in a dose-dependent manner and persisted through 1 month of recovery at 250 mg kg− 1 day− 1. Increased kidney weights were observed at 25 (females only), 100, and 250 mg kg− 1 day− 1. These elevated weights persisted in the high dose after recovery and correlated with microscopic tubular hypertrophy (males only). Thyroid follicular hypertrophy was present at 100 and 250 mg kg− 1 day− 1 but was not present after recovery. Total fluorine in whole blood increased with continuous dosing and achieved steady state in approximately 42 days. Both plasma and urine fluoride levels were elevated in adose-dependent manner. Under the conditions of the study, the no-observed adverse effect level for this mixture was 25 mg kg− 1 day− 1 for subchronic toxicity.

Biochemical and Histopathological Effects of Chronic Fluorosis on Lung Tissues of First Generation Rats

ABSTRACTChronic fluorosis is a slow and progressive process causing symptoms related to several systems particularly musculo-skeletal and dental systems. This study is aimed at investigating the biochemical and histological effects of chronic fluorosis on first generation (F1) rat lung tissues.Adult Wistar albino rats were used in order to obtain F1 male rats. Female rats were mated with males at a 2:1 ratio. The pregnant rats were given drinking water containing 100 mg/L sodium fluoride during gestation period. The rats had labour at 21±2 days. During the lactation period the mother rats were given the similar fluoridated water (100 mg/L fluoride). After weaning period, the young animals (1st generation; F1) were given the similar fluoridated water for 4 months time. Then, 9 male rats (F1) were chosen randomly and were sacrificed, and the lungs were removed for biochemical and histological examination. Control group rats were given commercial water containing of 0.07 mg/L fluoride.In F1 rats, plasma fluoride levels and the levels of thiobarbituric acid reactive substance (TBARS) in the homogenates of lung tissues were found to be increased significantly when compared with the control group. There were markedly histological changes in lung tissues of F1 rats. Alveolar congestion, descuamation of alveolar epithelium, thickened interalveolar septae were observed. Mononuclear cell infiltrations and hyperemic vessels were evident in the parenchymal areas. Moreover, some emphysematous areas were observed. Our biochemical and histopathological results clearly show that chronic fluorosis causes a marked destruction in lung tissues of F1 rats.

Effect of Chronic Fluorosis on Lipid Peroxidation and Histology of Kidney Tissues in First- and Second-Generation Rats

This experiment was designed to investigate the lipid peroxidation and histological effects of chronic fluorosis on first- and second-generation rat kidney tissues. Sixteen virgin female Wistar rats were mated with eight males (2: 1) for approx 12 h to obtain first-generation rats. Mating was confirmed by the presence of sperm in vaginal smears. Sperm in vaginal smears was observed in 10 of 16 rats (d 0). These rats were identified as pregnant and included in this experiment. Pregnant rats were divided into two experimental groups (control and fluoride-supplemented), each containing five rats. The pregnant rats in the fluoride-supplemented group were exposed to 30 mg/L sodium fluoride (NaF) in commercial drinking water containing 0.07 mg/L NaF throughout the gestation and the lactation periods. After the lactation period, young animals (first generation [F1]) were exposed to the same amount of NaF in drinking water for 4 mo. At the end of the 4-mo experimental period, nine randomly chosen male rats (F1) were sacrificed, and the kidneys were removed for the histological and lipid peroxidation examinations. The remaining eight female rats were mated with four males (2: 1) for approx 12 h to obtain second-generation rats. Six female were identified as pregnant, and treated similarly throughout the gestation and the lactation periods. After the lactation period, the young male rats (second-generation male rats [F2]) were also treated similarly for 4 mo. At the end of the 4-mo experimental period, nine randomly chosen male rats (F2) were sacrificed, and the kidneys were removed for the histological and lipid peroxidation examinations. The rats in the control groups underwent the same procedure without NaF supplementation. It was found that the plasma fluoride and kidney TBARS levels of fluoride-supplemented F1 and F2 rats were higher than controls. Hydropic epithelial cell degenerations and moderate tubular dilatation were observed in some proximal and distal tubules. There were markedly focal mononuclear cell infiltrations and hemorrhage at some areas of the interstitium, especially at the corticomedullar junction. Mononuclear cell infiltrations were also evident in some peritubular and perivascular areas. Most of the vascular structures were congestive. Many Bowman capsules were narrowed. The severe degenerative changes in most of the shrunken glomerules and vascular congestion were also observed.

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

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

Disturbed enamel formation in wild boars (Sus scrofa L.) from fluoride polluted areas in central Europe

The pathological alterations of enamel structure in the teeth of wild boars from fluoride polluted areas in N-Bohemia (Czech Republic) and S-Saxony (Germany) were studied on a macroscopic and a microscopic level. Mandibular bone fluoride concentration (mg F(-)/kg, dry wt; mean +/-SD, individuals <24 months of age) in the specimens from N-Bohemia (754.3+/-149.6) and S-Saxony (490.8+/-135.1) was significantly higher than that of controls (free of dental fluorosis), originating from the western part of Germany (304.7+/-91.0). Fluoride content in bulk enamel (mg F(-)/kg, ash wt) of fluorotic permanent teeth from N-Bohemia (382.1+/-165.2) and S-Saxony (125.0+/-38.3) was likewise significantly increased over that of non-fluorotic control teeth from W-Germany (33.6+/-26.7). Macroscopically, fluorosed wild boar enamel exhibited opacity and discoloration of varying extent, accentuated perikymata as well as hypoplastic and posteruptive surface defects. Microradiographic and scanning electron microscopic analyses revealed enamel subsurface hypomineralization, accentuated Retzius lines and occurrence of broad, hypomineralized incremental bands of abnormal structure underlying hypoplastic enamel surface defects. The presence of zones of aprismatic enamel was associated with these bands. Incremental bands with altered enamel structure and enamel surface hypoplasias, both denoting a severe disturbance during the secretory stage of amelogenesis, have previously been observed in rodents following acute parenteral fluoride dosing. It is concluded that in the chronically fluoride exposed wild boars periods of especially elevated plasma fluoride levels exerted an acute toxic effect on the secretory ameloblasts. A feature not previously reported from fluorosed enamel was the occurrence of canal-like structures that originated at the broad incremental bands and extended into the external enamel. The presence of these canals presumably results from a delay in the resumption of secretory activity by groups of ameloblasts following a fluoride insult. Based on experimental evidence in domestic pigs and in sheep, the overall subsurface hypomineralization of fluorosed wild boar enamel is attributed to a disturbance of enamel maturation. The distribution of fluorotic enamel changes within the dentition of the wild boars could be related to the developmental sequence of tooth formation in the species. Teeth whose crown formation took place prenatally (deciduous teeth) or largely pre-weaning (permanent first molars) exhibited no or only moderate fluorotic enamel alterations. Based on the extension of enamel surface hypoplasias along the coronoapical axes of the tooth crowns, the timing of excess fluoride exposure that caused a marked disruption of enamel matrix secretion was estimated in specimens with a known date of death. The results indicate that the wild boars had been exposed to a particularly severe fluoride impact during autumn and winter of their first year of life.