Smart Hesperidin/Chitosan Nanogel Mitigates Apoptosis and Endoplasmic Reticulum Stress in Fluoride and Aluminum-Induced Testicular Injury

Fluoride and aluminum are ubiquitous toxic metals with adverse reproductive effects. The citrus flavonoid hesperidin has protective activities but poor solubility and bioavailability. Nanoparticulate delivery systems can improve flavonoid effectiveness. We conducted this study to prepare a pH-responsive chitosan-based nanogel for hesperidin delivery and evaluate its effectiveness against sodium fluoride (NaF) and aluminum chloride (AlCl3) induced testicular toxicity in mice. The nanogel was synthesized using 2 kGy gamma irradiation, enabling a size under 200 nm and enhanced hesperidin release at pH 6 matching testicular acidity. Male mice received 200 mg/kg AlCl3 and 10 mg/kg NaF daily for 30 days. Hesperidin nanogel at 20 mg/kg was administered orally either prophylactically (pretreatment) or after intoxication (posttreatment). The results showed that AlCl3 + NaF induced severe oxidative stress, hormonal disturbance, apoptosis, and endoplasmic reticulum stress, evidenced by significant changes in the studied parameters and testicular histological damage. Hesperidin nanogel administration significantly inhibited oxidative stress markers, restored luteinizing hormone (LH), follicle-stimulating hormone (FSH), and testosterone levels, and alleviated tissue damage compared to the intoxicated group. It also downregulated the expression level of pro-apoptotic genes Bax, caspase-3, caspase-9, and P38MAPK, while upregulating the expression level of the anti-apoptotic BCL2 gene. Endoplasmic reticulum stress sensors PERK, ATF6, and IRE-α were also downregulated by the nanogel. The chitosan-based nanogel enhanced the delivery and efficacy of poorly bioavailable hesperidin, exhibiting remarkable protective effects against AlCl3 and NaF reproductive toxicity. This innovative nanosystem represents a promising approach to harnessing bioactive phytochemicals with delivery challenges, enabling protective effects against chemical-induced testicular damage.

Pan India fluoride hazard assessment in groundwater

Fluoride (F¯) contamination in groundwater in India has gained global attention due to human health hazards. India's hydrogeological heterogeneity, spatio-temporal variability of F¯, and health hazards due to geogenic and geo-environmental control pose unique challenges. Addressing these with only a single region-specific study is not possible. Therefore, this study provides an in-depth, holistic analysis of pan India F¯ contamination, controlling factors, and health hazards using a coupled advanced geostatistical and geospatial approach. Alarming F¯ contaminations are identified in Rajasthan, Telangana, Western Andhra Pradesh, Eastern Karnataka, Parts of Haryana, Gujarat, Madhya Pradesh, Tamil Nadu, Uttar Pradesh, Jharkhand, Bihar, and Chhattisgarh. Probabilistic health-risk evaluation using hot-spot, showed similar spatio-temporal distribution of F¯ contamination. The hazard quotient (HQ) for high F¯ shows more adversity to children than adults. Nationally, 8.65 % and 7.10 % of pre- and post-monsoon sites exceed the recommended safe limit of 1.50 mg/L. The highest average F¯ concentration is in Rajasthan. Very high-risk skeletal fluorosis is possible at around ≤ 2 %, whereas dental caries due to deficiency in F¯ concentration is approximately 40 %. A decisive hierarchy of lithology, geomorphology, soils, and lineaments control are identified on F¯ contamination. Climatic conditions are pivotal in governing all these controlling variables. Thus, in arid/semi-arid dry western regions, F¯ contamination is much higher than in the humid areas. Integration of strengths, weaknesses, opportunities, and threats (SWOT) analysis with the results can aid policymakers and government authorities in achieving sustainable remedial measures for future adaptability.

Explorations of the chemical constitution and aqueous solution status of caries-arresting silver(I)-diammine fluoride and silver(I)-fluoride products using high-resolution 19F NMR analysis. Spectroscopic and SEM investigations of their interactions with human saliva: evidence for the in vivo salivary-catalysed autoconstruction of Ag/AgCl-based nanoparticles (IV-SCAN)-part I

Introduction

Silver(I)-diammine fluoride (SDF) and silver(I)-fluoride (SF) complexes have been successfully employed for the arrest of dental caries for many years. However, to date there are very few studies available reporting on the molecular structural compositional and solution status of these agents [typically applied as highly-concentrated 38% (w/v) solutions]. Here, we explored the solution status and chemical constitution of commercially-available SDF and SF products, and secondly investigated the multicomponent interplay of these products with biomolecules present in intact human whole-mouth salivary supernatants (WMSSs) in vitro.

Methods

High-resolution 19F NMR analysis was employed to explore SDF and SF product solutions, and to determine WMSS fluoride (F-) concentrations, whereas ammonia (NH3) release form SDF was tracked by 1H NMR spectroscopy. SEM and thin-film FTIR-ATR analyses were employed to explore the atomic and molecular compositions of sequentially-generated AgCl deposits and chromophoric Ag/AgCl nanoparticles (CSNPs); the time-dependent generation of the latter was followed spectrophotometrically.

Results

19F NMR spectra of aqueous SF solutions contained a very broad F- signal (Δv1/2 70 Hz), demonstrating that much of its solvated F- content was rapidly exchanging with Ag(I) on the NMR timescale, but those of SDF had a much sharper resonance, similar to that of "free" F- (4 Hz). Moreover, further NMR results revealed that a popular SDF product contained high molar excesses of both F- and NH3. Treatment of WMSSs with SDF and SF generated an off-white precipitate, which slowly developed into CSNPs at 23°C; SEM demonstrated high contents of both silver and chloride in this material (ca.1:1 atomic content ratio). FTIR-ATR analysis found that the CSNPs formed contained a range of salivary biomolecules, which appear to encapsulate the Ag/AgCl core (significant thiocyanate contents were also found). In conclusion, NMR results acquired demonstrated that SF, but not SDF, product solutions feature rapidly-exchanging F - between its "free" and Ag(I)-bound forms, and that SDF contains large excesses of both F- and its NH3 ligands. Characterised AgCl deposits and CSNPs were sequentially produced from the interactions of these complexes with WMSS biomolecules.

Discussion

In view of their well-known microbicidal and cariostatic properties, the observed autobioconstruction of CSNPs involving salivary catalysis is of much therapeutic significance.

Effect of naringin on sodium fluoride‑induced neurobehavioral deficits in Wistar rats

There is a lack of treatment for the detrimental effects of fluorosis. Sodium fluoride at a concentration of 10 ppm induces stress, depression and memory impairment in adult Wistar rats. Naringin, a flavanone glycoside isolated from citrus fruits such as lemons and oranges, possesses anti-inflammatory, antioxidant and neuroprotective properties; therefore, it was used for treatment of fluoride induced toxicity in the present study. Adult Wistar rats were divided into eight groups (n=8). The normal control (NOR) group was provided with normal tap water. The sodium fluoride (FLU)10 group received water containing 10 ppm sodium fluoride for 60 days. The treatment groups (FLU10NAR100 and FLU10NAR50) received drinking water with 10 ppm sodium fluoride ad libitum along with Naringin 100 and 50 mg/kg body weight (bw) per oral gavage, respectively. The NAR100 and NAR50 groups received Naringin 100 and 50 mg/kg bw. The PRONAR100 and PRONAR50 groups received Naringin 100 and 50 mg/kg bw for the first 15 days and then subsequently received FLU10 ppm for 60 days (total of 75 days). All animals were subjected to behavioural tests consisting of the open field test (OFT), forced swim test (FST) and novel object recognition test (NORT). After euthanasia, the hippocampus and prefrontal cortex were stained with Cresyl violet. To measure the oxidative stress caused by fluoride and its effect on antioxidant levels, estimation of reduced glutathione (GSH) by Ellman's method, lipid peroxidation (LPO) measured in terms of the MDA:thiobarbituric acid reaction and catalase was performed. To evaluate the effect of fluoride on activity of acetylcholine, estimation of acetylcholinesterase (AChE) by Ellman's method was performed. In NORT and FST, significant changes (P<0.05) were present in the FLU10NAR100 and FLU10NAR50 groups compared with the FLU10 group, showing recovery from memory deficit and depression. The OFT results were insignificant. The LPO was reduced in all the other groups except the FLU10 group, with statistically significant changes. Catalase activity was significantly lower in FLU10 as compared with the NAR100, NAR50, PRONAR100 and PRONAR50 groups. GSH and AChE activities did not show significant changes as compared with the FLU10 group. The CA3 and prefrontal cortex viable and degenerated neuron count in the FLU10 group were insignificant compared with all other groups, except for the NAR100 and NAR50 groups. Thus, Naringin can be a useful drug to avoid the neurological effects of fluoride.

Prevalence of Skeletal Fluorosis in Northern Tanzania: A Follow-Up Study

OBJECTIVES

Skeletal fluorosis is a metabolic bone disease caused by excessive exposure to fluoride, predominantly through contamination of drinking water. This study aimed to identify all cases of skeletal fluorosis in Tindigani village situated in Northern Tanzania. This was done following changes in drinking water sources after a previous prevalence study in 2009 in this population.

METHODS

In a door-to-door cross-sectional study of Tindigani village, a sample of residents was assessed for skeletal fluorosis and dental fluorosis. Diagnosis of skeletal fluorosis was based on pre-defined angles of deformity of the lower limbs. Dental fluorosis was diagnosed and graded using the Thylstrup and Fejerskov Index. Samples from current drinking water sources underwent fluoride analysis.

RESULTS

Tindigani village had a population of 1,944 individuals. Of the 1,532 individuals who were screened, 45 had skeletal fluorosis, giving a prevalence of 3.3% (95% CI=2.4, 4.3). Dental fluorosis was present in 82.5% of those examined (95% CI=79.8, 85.3). Dental fluorosis was present in all individuals with skeletal fluorosis and at higher grades than in the rest of the population. Drinking water samples were collected from 28 sources. These included piped, surface, well, and borehole water sources. Fluoride concentrations ranged from 0.45-38.59 mg/L of fluoride.

CONCLUSIONS

Skeletal fluorosis is an ongoing but preventable health problem in the current population. The delivery of sustainable low fluoride piped water to this community would be of clear health benefit. This has been addressed at a local level.

Hydrogeochemical and multivariate statistical approaches to investigate the characteristics of groundwater quality in fluoride-enriched hard rock region in Tirupathur district of Tamil Nadu, India

Fluoride pollution is a major issue worldwide, posing health risks such as dental and skeletal fluorosis. This study was conducted in fluoride enrichment hard rock regions of Vaniyambadi and Ambur talks in Tirupathur district, Tamil Nadu. Four hundred eighty groundwater samples were collected from May 2021 to April 2022 and grouped as summer, southwest monsoon (SWM), northeast monsoon (NEM), and winter. Maximum concentration of fluoride was found to be 4 mg/L in the summer season in Vellakuttai region of Vaniyambadi taluk. The study aims to investigate the hydrogeochemical process and mechanism influencing groundwater chemistry and it also provides the confirmation of exploratory data analysis in groundwater quality using structural equation modeling. The Piper and Gibbs diagrams illustrate the rock-water interaction and anthropogenic sources that contribute to the NaHCO3 and NaCl-type waters, respectively. Multivariate statistical analysis such as hierarchical cluster analysis (HCA), principal component analysis (PCA), multiple linear regression (MLR), and structural equation modeling (SEM) has been carried out to determine the groundwater quality. HCA manifests the nature and sources of groundwater, whereas PCA divides all the physicochemical parameters into two PC loadings, accounting for 97.46%, 99.46%, 99.18%, and 98.93% of cumulative % of variance during the summer, SWM, NEM, and winter seasons, respectively. PC1 has a higher loading factor to Cl, Ca, and Mg, whereas PC2 has a higher loading factor to Na, HCO3, SO4, and NO3. The results of the MLR model provide higher accuracy in detecting the contamination factors associated with the environment and natural rocks. SEM revealed the goodness-of-fit indices 0.993, 0.999, 1.000, and 0.999 in summer, SWM, NEM, and winter, respectively. Hence, this study provides insight view of variation of fluoride concentration in groundwater in different seasons and also mentions the factors that influence fluoride concentration in Vaniyambadi and Ambur taluk.

Pediatric Dental Fluorosis and Its Correlation with Dental Caries and Oral-Health-Related Quality of Life: A Descriptive Cross-Sectional Study among Preschool Children Living in Belagavi

AIM

This study aims to assess the prevalence of dental fluorosis and its association with dental caries, oral health behaviors, oral-health-related quality of life and parents' perceptions among preschool children in the 3-5-year-old preschool children living in the Belagavi district of Karnataka, a non-endemic fluorosis region.

METHODS

A descriptive cross-sectional questionnaire-based study was conducted among 1200 individuals of the preschool population from 48 government-sponsored child-care development centers in Belagavi, Karnataka, over a three-month period. They were examined following the Dean's fluorosis index (1942) and dmft (decayed, missed, and filled) scores of the participants were also recorded. Parents' perception of oral health was assessed using the self-administered Early Childhood Oral Health Impact Scale (ECOHIS). SPSS software (version 20) was used for statistical analysis. Chi-square test computed categorical data. One-way ANOVA test was used for multiple group comparisons. p < 0.05 was considered statistically significant.

RESULTS

Of the 1200 children examined, 10 (0.83%) children exhibited dental fluorosis. Of the 10 children having fluorosis, six had fluorosis present on two or more of their primary teeth, and four had fluorosis on four or more teeth. The mean dmft score was 3.01 ± 1.38 to 3.60 ± 1.72 in 3-5-year-old children, respectively, with statistical significance difference (p < 0.001). The mean score of oral health-related quality of life was 10.74 ± 2.06, which was significantly correlated to the child's age and parents' education level (p < 0.05).

CONCLUSION

The study shows a negligible amount of prevalence of dental fluorosis in the non-endemic fluorosis residential district. It also elucidates that children from lower and lower-middle socioeconomic status are more prone to suffer from dental fluorosis as compared to other groups. The mean score of ECOHIS increased proportionally with the caries experience, indicating a significant relationship between the dmft and ECOHIS score. Deciduous dentition fluorosis is often neglected, especially in areas that are not considered endemic for fluorosis and with only optimum fluoride levels in their groundwater, which supports the disease's nature as multi-factorial and shows that a broader perspective is of prime importance to assess, diagnose, and prevent dental fluorosis among the preschoolers, thereby appraising their overall health and hygiene status.

Seasonal variations in the groundwater fluoride of Swarna river basin in southern India: A GIS-based study

Objectives:

The study aimed (1) to assess fluoride concentration of groundwater along the Swarna river basin in Udupi District; (2) to investigate variations in fluoride concentration with respect to rainfall status in Udupi district; and (3) to develop a spatial distribution map for the groundwater fluoride concentration in Udupi district.

Materials and Methods:

Water samples were procured from 30 different sampling points across three time zones in a year: pre-monsoon, monsoon, and post-monsoon. The samples thus collected were analyzed for fluoride ion concentration using fluoride ion selective electrodes (Orion™). Mean determination readings at each time zone were calculated. Repeated-measures analysis of variance was done to analyze whether there was a difference in the concentration of fluoride over different time zones.

Results:

The mean (SD) pre-monsoon concentration was 0.25 (± 0.07) ppm, whereas the mean monsoon and post-monsoon concentrations were 0.26 (± 0.09) and 0.57 (± 0.23) ppm, respectively. There was a significant increase in post-monsoon fluoride levels when compared with the pre-monsoon and monsoon levels.

Conclusion:

The groundwater fluoride concentration in the Swarna river basin was found acceptable for human consumption at all the sampled sites and across all time zones. As the fluoride concentration was found to be lower than the recommended values for dental caries prevention at most of the sampling sites, use of topical fluorides needs to be encouraged.

Effect of fluoride on bone and growth plate cartilage

The use of fluoride (F) for therapeutic purposes is controversial and its toxicity is a health problem. The aim of this study was to evaluate the effect of F on endochondral ossification in growing rats. Twenty-four rats of 21 days were divided into 4 groups which received 0, 20, 40 or 80 μmol F/100 g body weight/day for 30 days, through an orogastric tube. Histological evaluation of growth plate cartilage (GPC) and primary and secondary bone were analyzed on sections of the metaphysis of tibias. Total thickness of the GPC (GPC.Th), thickness of resting zone (RZ.Th), proliferative zone (PZ.Th) and hypertrophic zone (HZ.Th); bone volume (BV/TV), trabecular thickness (Tb.Th), trabecular number (Tb.N), trabecular separation (Tb.Sp), and apoptosis by the TUNEL were measured. A hyperplasia of the proliferative zone and a significant increase in PZ.Th with 40 and 80 μmol F without changes in GPC.Th were found. In the secondary trabecular bone, presence of immature trabeculae, peritrabecular inflammatory foci and sinusoidal dilatation were observed. A significant decrease in BV/TV was also found due to a decrease in Tb.Th and a progressive increase was observed in the number of apoptotic nuclei as the dose of F increased. In conclusion, results suggest that prolonged administration (30 days) of F negatively affect the endochondral ossification with increased chondrocyte proliferation and delayed maturity of new bone, causing inflammatory damage, edema, and increased apoptotic bone cells.

MiR-29b-3p aggravates NG108-15 cell apoptosis triggered by fluorine combined with aluminum

The mechanism of learning and memory impairment induced by the combination of fluorine and aluminum (FA) is not fully understood. The results of our previous research demonstrated that miR-29b-3p is a differentially expressed miRNA in the hippocampi of rat offspring exposed to FA; this miRNA is related to learning and memory and apoptosis. Based on these findings, in vitro studies were designed to assess the role of miR-29b-3p in neuronal apoptosis caused by the coexistence of FA. In the present study, the viability of mouse neuroblastoma-rat glioma hybrid cell (NG108-15 cell) was analyzed using Cell Counting Kit-8 (CCK-8). Apoptosis was detected by a Novocyte Flow Cytometer. Relative mRNA and protein expression levels were evaluated by real-time fluorescence quantitative PCR (qRT-PCR) and Western blotting (WB), respectively. The results showed that FA aggravated NG108-15 cell apoptosis by inhibiting dual-specificity phosphatase-2 (Dusp2) via increased miR-29b-3p. Accordingly, a dual-luciferase reporter assay showed that miR-29b-3p modulated Dusp2 protein levels by targeting its 3'-untranslated region. These findings show, for the first time, that miR-29b-3p is involved in neuronal apoptosis triggered by FA by targeting Dusp2.

Selenium may suppress peripheral blood mononuclear cell apoptosis by modulating HSP70 and regulate levels of SIRT1 through reproductive hormone secretion and oxidant stress in women suffering fluorosis

Excessive taking fluoride (F) causes severe damage to reproductive system through stimulation of apoptosis and oxidant stress. Selenium (Se) may promote anti-oxidant enzymes and invert cell apoptosis. The aim of this study was to investigate the effect of Se on peripheral blood mononuclear cell (PBMC) apoptosis and oxidant stress in women with fluorosis. Sixty women were divided into three groups according to serum and urine fluoride and hair Se as High F + high Se group, High F group and Control group. The activities of anti-oxidant enzymes, malondialdehyde (MDA) and Se were measured. The levels of sirtuin type 1 (SIRT1), estradiol (E₂), follicle-stimulating hormone (FSH) and luteinizing hormone (LH) were measured by enzyme-linked immune sorbent assay (ELISA) kits. The expression of protein and apoptosis rate were detected by Western blot and Flow cytometry. The levels of E₂, anti-oxidant enzymes in High F group were significantly lower than that in Control group, while the levels of SIRT1 and MDA were significantly higher. The levels of anti-oxidant enzymes and heat shock protein 70 (HSP70) were significantly increased in High Se + high F group while the expression of caspase-3 was significantly increased in high F group. The levels of LH and FSH in serum were significantly increased in High F group and High Se + high F group. Therefore, Se alleviates apoptosis induced by F through improving the expression of HSP70 and reduces oxidative stress by regulating levels of SIRT1 and anti-oxidant enzymes, and the secretion of certain reproductive hormones.

Radionuclide activity concentration in soil, granites and water in a fluorosis endemic area of India: An oral health perspective

Background

The idea that hilly areas have a high background radiation which in turn is linked to dental fluorosis is widely held by many in India. There is little evidence to confirm this.

Objective

The study aimed to investigate the level of environmental radionuclide in order to determine any interrelationship between radionuclide and dental fluorosis in Pavagada, a fluorosis endemic area of Karnataka, India.

Methods

Gamma radionuclides (Th232, Ra226 and K40) were determined by high purity germanium (HPGe) gamma-ray spectrometer (Bq Kg-1) using a 50% relative efficiency p-type broad energy HPGe detector. Fluoride was estimated using fluoride Ion-selective electrode (ISE). Fluorosis was assessed using WHO diagnostic criteria.

Results

The average mean +_SD activity concentration in soil for K40 was detected between 416.6 ± 9.3 and 769.1 ± 15.0. Th232 was estimated between 13.6 ± 0.6 and 57.6 ± 1.3; and Ra226 was found between 6.4 ± 0.4 and 21.6 ± 0.7. Similarly, the mean activity concentration detected (Bq kg-1) in granite for K40 ranged between 259.8 ± 6.9 and 1608.5 ± 26.9. The activity concentration of Th232 ranged between 26.4 ± 0.8 and 57.6 ± 1.3: and that of Ra226 was between 6.6 ± 0.3 and 21.6 ± 07. Drinking water contains 2.98 ppm of fluoride. Dental fluorosis was diagnosed as mild to moderate.

Conclusion

The radionuclide activity in water, soil and granites were below the detection limit. Hence, the study revealed no association of fluorosis and radionuclide level in Pavagada, Karnataka, India. This helps resolve an ambiguity.

Differential Expression of miRNAs in the Hippocampi of Offspring Rats Exposed to Fluorine Combined with Aluminum during the Embryonic Stage and into Adulthood

A previous study from our team found that continuous exposure to fluorine combined with aluminum (FA) impaired the neurobehavioral reflexes, spatial learning, and memory of offspring rats. To date, the specific mechanisms for these changes are unclear. Here, high-throughput sequencing was utilized to analyze the microRNA (miRNA) profile of the hippocampi in the offspring of rats exposed to FA during the embryonic stage and into adulthood through tap water supplemented with NaF and AlCl₃ at concentrations of (0, 0); (60, 600); (120, 600); and (240, 600) mg/L, respectively. qRT-PCR was performed to validate the reliability of the sequence data. Twenty differentially expressed miRNAs were selected for further analysis using bioinformatics tools. Several genes related to neuromodulation were found to be regulated by miR-10a-5p, miR-34b-5p, and miR-182, which might be harmful to normal nerve function. The protein levels of brain-derived neurotrophic factor (BDNF) and tyrosine receptor kinase B (TrkB) in hippocampus were markedly downregulated. These data suggest that miR-10a-5p, miR-34b-5p, and miR-182 and BDNF-TrkB signaling pathway are involved in mechanisms of hippocampal damage in the offspring of rats exposed to FA. HIGHLIGHTS: • Multiple miRNAs were significantly differentially expressed in offspring rat hippocampus after fluorine combined with aluminum (FA) exposure. • Twenty differentially expressed miRNAs might mediate FA-induced developmental neurotoxicity. • MiR-10a-5p, miR-34b-5p, and miR-182 were closely related to neurotoxic signaling of FA. • The BDNF-TrkB learning and memory-associated pathway was downregulated in the hippocampus after FA exposure.

Synergistic oxidative impact of aluminum chloride and sodium fluoride exposure during early stages of brain development in the rat

Aluminum is widely used in industry and in cooking utensils, especially in countries with low economic and social standards. Fluoride is also used in industry, a major component of toothpaste and is added to the drinking water in many countries to fight teeth decay and cavities. Consequently, the coexistence of aluminum and fluoride is highly probable. Growing evidence indicates that environmental pollutants during the early stages of embryonic development may reprogram the offspring's brain capabilities to encounter oxidative stress during the rest of their postnatal life. This study investigated the impact of sodium fluoride (NaF, 0.15 g/L) and aluminum chloride (AlCl₃, 500 mg/L) added, individually or in combination, to the deionized drinking water starting from day 6 of gestation until just after weaning, or until the age of 70 days postnatal life. A significant decline was observed in tissue contents of vitamin C, reduced glutathione, GSH/GSSH ratio, and the total protein, as well as in the activities of Na⁺/K⁺-ATPase and superoxide dismutase (SOD) in almost all cases. On the contrary, lipid peroxidation and NO, as total nitrate, exhibited a significant increase in comparison with the corresponding control. Based on the present results, administration of Al and NaF, alone or in combination abated the quenching effects of the antioxidant system and induced oxidative stress in most brain regions under investigation. In conclusion, aluminum and fluoride are very noxious environmental pollutants that interfere with the proper functions of the brain neurons and their combination together aggravates their hazard.

Fluoridation and county-level secondary bone cancer among cancer patients 18 years or older in New York State

The decision whether to fluoridate drinking water continues to be controversial in some communities. Dental and skeletal fluorosis in response to chronic fluoride overexposure are cited as reasons to avoid community water fluoridation in spite of evidence of the oral and skeletal health benefits fluoridation confers. Community fluoridation of ~ 1 mg/L fluoride has not been found to be associated with primary bone cancer but is associated with improved bone strength. No studies have examined fluoride exposure and secondary bone cancer, a common metastasis with significant morbidity. We hypothesize that fluoridation could diminish the likelihood of secondary bone cancer due to its role in bone fortification. We examined the association between community water fluoridation category and prevalence of secondary bone cancer from 2008 to 2010 among cancer patients of 18 years of age or older in counties in New York State. Relative to counties with less than 25% of the water supply fluoridated, we report no association between secondary bone cancer among cancer patients in counties with 25-75% of the water supply fluoridated (β = 0.02, p = 0.96) and among those in counties with > 75% fluoridated (β = 0.02, p = 0.97). We found no evidence of an association between community water fluoridation category and secondary bone cancer from 2008 to 2010 at the county level in New York State.

Highly acidic pH values of carbonated sweet drinks, fruit juices, mineral waters and unregulated fluoride levels in oral care products and drinks in India: a public health concern

PURPOSE

The objective of this study was to quantify and assess the concentrations of fluoride in commonly used oral care products, fruit juices, bottled waters, soft drinks, favoured bottled milk and milkshakes and to determine the pH of carbonated sweet drinks and drinks marketed in India.

MATERIALS AND METHODS

Various commercial brands of dentifrices, toothpowders, mouthwashes, bottled waters, sweet carbonated drinks and fruit juices were collected randomly from different outlets in Mangalore city, Karnataka, India. A fluoride ion-selective electrode was employed to estimate the fluoride concentrations. A standardised pH meter was used to detect pH in the drinks.

RESULTS

The fluoride level in toothpastes ranged between 96 and 1397 mg/l, whereas in toothpowder the fluoride content ranged from 35 to 1380 mg/l and mouthwash fluoride concentrations varied from 6 to 228 mg/l. The fluoride level in bottled waters ranged between 0.10 and 0.12 mg/l, and that in fruit juices between 0.09 and 0.21 mg/l. Most of the carbonated sweet drinks and fruit juices had highly acidic pH values which ranged between 2.62 and 4.26.

CONCLUSION

Of the wide variety of dentifrices and toothpowders available in India, most brands do not indicate the fluoride levels on their packaging or inserts. Similarly, the unregulated acidic pH values of carbonated sweet drinks are not only potentially contributing to non-carious tooth loss (enamel erosion and dentine erosion), but are also a contributing factor to the weight gain observed in Indian adolescents.