Fluoride Exposure Effects and Dental Fluorosis in Children in Mexico City

Health Risk Assessment in Mexican Children Exposed to Fluoride from Sweetened Beverages

The primary source of fluoride exposure is groundwater, but evidence suggests that beverages and food are additional fluoride sources. Intake of these products at an early age affects the optimal functioning of soft organs. An increase in sweetened beverage consumption by the pediatric population has been reported, suggesting an increase in fluoride exposure. The objectives of this study were to determine the fluoride concentrations in beverages and analyze the risk to human health from fluoride exposure to sweetened beverages consumed by children. Eighty-two sugar-sweetened beverages produced in different Mexican states were analyzed. The fluoride determination was carried out with an ion-selective electrode. The highest fluoride concentration was 1.92 mg/L; 73.2% of beverages showed fluoride values above permitted limits. Low-cost beverages had the highest fluoride values, suggesting that the water used for their production does not comply with fluorine regulations. According to the risk assessment in children from 3 to 6 years, the daily consumption of juices and sodas with concentrations that exceeded the normative of 0.7 mg/L could represent a risk to dental fluorosis development. It is crucial to control fluoride and regulate its concentrations in beverages for children to ensure food safety, especially in areas of endemic hydrofluorosis.

Public Knowledge and Perception of Drinking Water Quality and Its Health Implications: An Example from the Makueni County, South-Eastern Kenya

Due to the semi-arid nature of Makueni County in South-Eastern Kenya, there is a high dependence on groundwater resources for domestic use. Reliance on this source of potable water may have health implications for the population, given the presence of several naturally occurring and potentially harmful elements reported from aquifer source rocks, soil, and water in the area. A survey involving questionnaires and focus group discussions (FGDs) was conducted with 115 individuals to determine the local population’s knowledge, attitude, and perceptions of their drinking water quality and its health impacts. The results show that most respondents (67%) preferred piped water because it was pre-treated and not saline. Only 29% of the respondents were very satisfied with the taste of their drinking water, while the rest complained about varying salinity levels, ranging from slightly salty to very salty. This low satisfaction might have influenced the low daily drinking water consumption (1–2 L) by most respondents. Health issues reported by many (43%) respondents in the area include diarrhoea and gastrointestinal upsets, which may be associated with the saline nature of the drinking water. Elevated fluoride (F−) in the local groundwater was reported, and the health effects remain a concern. Although 91% knew someone with dental fluorosis, 53% did not know the deleterious effects of high F− in drinking water. Most respondents (59%) associated the salty nature of the water with dental fluorosis, and as a result, 48% avoided drinking the salty water to prevent the condition. Despite the high prevalence and known psycho-social effects, most people did not perceive dental fluorosis as a severe health threat. The increased health risks associated with high salinity and high F− in drinking water in Makueni County are poorly understood by most residents, regardless of their education, gender, or age. This warrants an immediate public health education programme and detailed epidemiological studies to determine all the health effects associated with naturally occurring, potentially harmful elements in groundwater in the area.

External control of fluoridation in the public water supplies of Brazilian cities as a strategy against caries: a systematic review and meta-analysis

Background

Among the methods currently available to provide fluoride in population levels, fluoridated water is the most successful for presenting high efficacy, safety and good cost–benefit. However, recent studies on external control have shown great variability of fluoride concentrations in the water from treatment stations in Brazilian cities, which must present concentration between 0.6 and 0.8 mg/L to be considered acceptable in most cities. Thus, this study aimed to perform a systematic review of the literature to assess the adequacy of fluoride concentration in the water in Brazilian cities using external control.

Methods

The protocol was registered in PROSPERO. Six databases were used as primary search sources and three databases were used to partially capture the "gray literature". Only observational studies that assessed the fluoride concentration of artificially fluoridated water from the public supply network were included. The JBI Critical Appraisal Tools for Systematic Reviews was used to assess the risk of bias of the studies. A proportion meta-analyses using random-effect models were performed. The heterogeneity between studies was determined by I² statistic. Meta-regressions were conducted to identify relevant moderators to be used in stratified meta-analyses. Publication bias was investigated by Egger’s tests.

Results

The search provided 2038 results, from which 14 met the eligibility criteria and were included in the data extraction of the review. Overall, the water samples were collected from 449 different sources in three Brazilian regions. Thirteen studies presented a low risk of bias. The mean concentration of fluoride ranged from 0.17 to 0.89 ppmF. The meta-analyis demonstrated that more than half of the water samples analyzed had fluoride concentration levels outside the acceptable range (56.6%; 95% CI 45.5; 67.3), with high heterogeneity.

Conclusion

More than half of the public water supply analyzed in the studies selected had fluoride concentration levels outside the acceptable range, which may affect the risk of developing oral diseases in the Brazilian population, having an important impact on public health.

Supplementary Information

The online version contains supplementary material available at 10.1186/s12903-021-01754-2.

The occurrence, severity degree, and associated risk factors of dental fluorosis among the 12-year-old schoolchildren in Jilin, China

This study aims to describe the occurrence, severity degree, and correlated risk factors of dental fluorosis among the 12-year-old schoolchildren of Jilin, China.We conducted a cross-sectional, observational, and descriptive study among 960 12-year-old schoolchildren in Jilin. The Dean index was utilized to evaluate the severity degree of dental fluorosis. A questionnaire was sent to the guardians of children. Community fluorosis index was measured to estimate the importance of enamel fluorosis for the whole population's public health. The logistic regression analysis was also utilized to identify the correlation between fluorotic teeth and the independent variables.Nine hundred sixty children were assessed. Among them, 480 (50%) were female. 30.5% of subjects had dental fluorosis, 7.19% had very mild dental fluorosis, 10.73% experienced mild dental fluorosis, 9.58% suffered moderate dental fluorosis, and 3.02% encountered severe dental fluorosis. The overall community fluorosis index was 0.73. The results of logistic regression showed that schoolchildren who brushed teeth more frequently (OR: 2.012, 95% CI 1.767-2.342), deficiency of parental supervision (OR: 4.219, 95% CI 3.887-4.573), and lived in rural areas (OR: 2.776, 95% CI 2.163-3.489) were more correlated with enamel fluorosis. Moreover, schoolchildren whose mothers or fathers were of high education level (OR: 0.336, 95% CI 0.217-0.413 and 0.346, 95% CI 0.113-0.512) and only child (OR: 0.378, 95% CI 0.213-0.415) were protective factors for dental fluorosis.In the Jilin province of China, the risk indicators for dental fluorosis include rural areas, more frequency of brushing, low educational background of parents, and deficiency of parental supervision.

Factors associated with dental fluorosis among Malaysian children exposed to different fluoride concentrations in the public water supply

OBJECTIVES

To determine the prevalence of dental fluorosis, and factors associated with its occurrence in two cohorts of children exposed to different fluoride concentrations in the Malaysian water supply.

METHODS

A cross-sectional study was conducted among lifelong residents (n = 1,155) aged 9 and 12 years old living in fluoridated and nonfluoridated areas. Malaysian children aged 12 years were born when the level of fluoride in the public water supply was 0.7 ppm while those aged 9 years were born after the level was reduced to 0.5 ppm. Fluorosis was blind scored using standardized photographs of maxillary central incisors using Dean's criteria. Fluoride exposures and other factors were assessed by parental questionnaire. Data were analyzed using descriptive statistics, Chi-squared analyses, and logistic regression.

RESULTS

Fluorosis prevalence was lower (31.9 percent) among the younger children born after the reduction of fluoride concentration in the water, compared to a prevalence of 38.4 percent in the older cohort. Early tooth brushing practices and fluoridated toothpaste were not statistically associated with fluorosis status. However, the prevalence of fluorosis was significantly associated with parents' education level, parents' income, fluoridated water, type of infant feeding method, age breast feeding ceased, use of formula milk, duration of formula milk intake, and type of water used to reconstitute formula milk via simple logistic regression. Fluoridated water remained a significant risk factor for fluorosis in multiple logistic regression.

CONCLUSIONS

Fluorosis was lower among children born after the adjustment of fluoride concentration in the water. Fluoridated water remained as a strong risk factor for fluorosis after downward adjustment of its fluoride concentration.

Assessment of Paediatricians' Oral Health Knowledge, Behaviour, and Attitude in the United Arab Emirates

Aim

Paediatricians' oral health knowledge is essential for early detection of disease, appropriate advice, and proper referral. Therefore, this study aimed to evaluate the knowledge, behaviour, and attitude of paediatricians practicing in the United Arab Emirates (UAE) regarding children's oral health. Study Design. Cross-sectional survey.

Methods

A questionnaire consisting of 16 questions was completed after piloting by a sample of randomly selected registered UAE paediatricians. Scores of knowledge (out of 9), behaviour (out of 4), and attitude (out of 3) were calculated. Statistical analysis was performed using Shapiro–Wilk, Mann–Whitney U, and Kruskal–Wallis tests. Statistical significance was set as P < 0.05.

Results

A total of 185 surveys were completed. Nearly half of the paediatricians (95 (51.4%)) identified the appropriate age for child's first dental visit; while 88 (47.6%) believed that the appropriate age to start brushing was after the eruption of the primary molars (2-3 yrs), and 132 (71.4%) believed that the ideal time to give sugary snacks is in between meals. 123 (66.5%) participants said that they would prescribe antibiotics to treat local dental sepsis without fever. Experienced paediatricians and those trained in Western countries had significantly better knowledge about oral health (P values 0.040 and 0.031 consecutively). The scores of attitude, behaviour, and knowledge were correlated, and a positive relationship between the scores of knowledge and behaviour was found (r = 0.241, P=0.001) and between scores of attitude and behaviour (r = 0.197, P=0.007).

Conclusions

The results demonstrated a general lack of knowledge of oral health aspects by UAE paediatricians. Furthermore, continuous education in the subject is recommended.

The association between the prevalence of dental fluorosis and the socio-economic status and area of residence of 12-year-old students in Uruguay

Objective: This study investigates the association between the prevalence and severity of dental fluorosis, the socio-economic status (SES) and area of residence among 12-year-old schoolchildren in Uruguay.Material and methods: The study was descriptive, cross-sectional, explanatory and observational. Subjects considered eligible were born in 1999 and had their parents' or guardian's prior consent. A questionnaire was used to identify SES according to Centro de Investigaciones Económicas Institute on four levels. Dental fluorosis was determined using the Thylstrup-Fejerskov (TF) index.Results: Of the 1544 students examined, 45.0% showed dental fluorosis. A TF index 1-2 was recorded in 29.3% of the subjects, TF 3 in 20.9%, TF 4 in 6.7% and TF 5-9 in 2.1%. In area 1 (the capital Montevideo city), 84.8% of the subjects had dental fluorosis, a value that was significantly higher than in the inland region (area 2, 24.4%) and border departments (area 3, 22.5%) (x² = 27.92, p < .0001). Students from families with a low socio-economic level showed less prevalence of dental fluorosis than those with a high level (x² = 14.58, p = .002).Conclusion: Significant differences exist in the prevalence of dental fluorosis in relation to place of residence and socio-economic level.

Effects of at-home bleaching and resin infiltration treatments on the aesthetic and psychological status of patients with dental fluorosis: A prospective study

OBJECTIVE

This study aims to evaluate the effect of the combination approach of at-home bleaching (HB) and resin infiltration (RI) techniques on different severity degrees of dental fluorosis (DF) and further analyze the psychological changes caused by HB and RI in patients.

METHOD

Twenty-two patients (4 males, 18 females, 27.8 ± 1.6 yrs) with 186 fluorotic teeth were included in this study and classified into mild (N = 56), moderate (N = 100) and severe (N = 30) DF groups according to the Dean's index. The treatment effects on patients with DF were assessed by questionnaires including the changes in patients' subjective evaluation of their teeth and psychological status before and after treatments. Standardized digital photographs were taken at each time point of the treatment process, including baseline (T1), after bleaching (T2), immediately after RI treatment (T3) and more than six months after RI treatment (T4). The color alterations (ΔE) between the fluorotic (F2) and the surrounding relatively sound areas (F1) were analyzed.

RESULTS

Bad tooth appearance caused 13.64% of patients often depressed, frustrated, or disappointed, whereas 72.72% occasionally had these feelings. After treatment, the satisfaction of DF patients regarding tooth appearance increased from 0% (satisfied) to 58.82% (satisfied) and 23.53% (very satisfied). Moreover, these treatments improved all patients' confidence in smiling, laughing and showing their teeth. The percentage of fluorotic teeth with ΔE values more than 3.0 and 3.7 units decreased gradually from T1 stage to T3 stage in mild and moderate DF groups (p < 0.05), whereas the ΔE value in T3 stage was significantly lower than that of T2 stage in severe DF group (p < 0.05). In T4 stage, no significant difference was observed in the ΔE values between T4 and T3 stages (p > 0.05).

CONCLUSION

This study shows the obvious positive aesthetic effect of HB and RI treatment on different severity degrees of DF and the great improvements in psychological discomforts.

CLINICAL SIGNIFICANCE

The combination treatment of RI and low concentration HB gel improves the aesthetics of DF and may have a stable effect after 6-months follow-up, suggesting that this approach is a valuable clinical choice for dentists to treat DF.

Oral health of 12-year-old children in Quito, Ecuador: a population-based epidemiological survey

BACKGROUND

There is a paucity of population-based surveys on oral health conditions in Ecuador. Thus, the aim of this study was to conduct an epidemiological survey with a representative sample of children aged 12 years from public schools of Quito, Ecuador. The aim of this initial report was to describe the methodology used in the survey, as well to present results regarding calibration procedures and prevalence of oral-health related outcomes.

METHODS

We invited 33 public schools' coordinators from the urban area of Quito, and 1100 children (12 years old) to take part in this study. Six trained and calibrated examiners conducted clinical examinations using oral mirrors and ball-ended probes to assess: dental caries, traumatic dental injuries, malocclusion, gingival bleeding, presence of calculus and fluorosis. Children also responded a questionnaire on Oral Health-Related Quality of Life (OHRQoL). Individual sociodemographic data was collected through a questionnaire sent to parents. Moreover, some contextual data on school environment (infrastructure conditions, promotion of health practices and negative episodes) were also evaluated. Prevalence values, crude and weighted by sampling weights, and 95% confidence intervals (95%CI) were calculated.

RESULTS

Nine hundred and ninety-eight children from 31 schools were examined from March to May 2017. The adjusted prevalence values (95%CI) for the six outcomes evaluated were: dental caries = 60.3% (55.3 to 65.0%); traumatic dental injuries = 20.7% (17.2 to 24.8%); dental fluorosis = 63.7% (58.5 to 68.5%); gingival bleeding = 92.0% (87.1 to 95.2%); presence of calculus = 69.9 (60.5 to 77.9%); and malocclusion = 25.8% (21.8 to 30.3%). Adjusted mean of number of decayed, missed or filled permanent teeth (DMF-T) was 1.61 (1.37 to 1.84). Results on OHRQoL and other contextual variables will be reported in other articles.

CONCLUSION

The prevalence of the majority of oral health problems in 12-year-old children from public schools in Quito-Ecuador was compatible with those observed in other similar cities. However, periodontal health and fluorosis seem to be highly prevalent in children from Quito.

Effect of Fluoride on Small Intestine Morphology and Serum Cytokine Contents in Rats

This study aimed to determine the effect of excessive fluoride (F) on the morphological characteristics of the small intestine and the contents of serum cytokines in rats. A total of 48 3-week-old healthy female Sprague-Dawley rats were randomly divided into four groups (n = 12). The control group was given deionized distilled water, while the F treatment groups were treated with water containing 25, 50, and 100 mg F^-/L. After 70 days of treatment, the duodenum, the jejunum, and the ileum were collected to measure the developmental parameters and the distribution of intestinal glycoproteins, goblet cells, and mast cells through Pannoramic Viewer, Periodic Acid-Schiff (PAS) staining, Alcian blue and periodic acid-Schiff (AB-PAS) staining, and toluidine blue staining, respectively. The contents of cytokines, namely, interleukin (IL)-1β, IL-2, IL-6, and tumor necrosis factor (TNF)-α, in serum were detected via enzyme-linked immunosorbent assay (ELISA). Results showed that the villus height, crypt depth, villus height to crypt depth ratio, goblet cells, glycoproteins, and mast cells of the small intestine significantly decreased (P < 0.05 or P < 0.01) in the F treatment group. The contents of IL-1β, IL-2, IL-6, and TNF-α were significantly lower in the F treatment group than in the control group (P < 0.05 or P < 0.01). In summary, excessive F intake impaired intestinal development and immune function by decreasing the developmental parameters and the distribution of immune cells, glycoproteins, and cytokines.

Threshold effects of moderately excessive fluoride exposure on children's health: A potential association between dental fluorosis and loss of excellent intelligence

BACKGROUND

Excessive fluoride exposure is associated with adverse health outcomes, but little is known of the effects of moderately chronic fluoride exposure on children's health.

OBJECTIVES

We conducted a cross-sectional study to explore the health impact of moderately excessive fluoride in drinking water.

METHODS

We recruited 2886 resident children, aged 7 to 13 years, randomly from endemic and non-endemic fluorosis areas in Tianjin, China. The fluoride levels in drinking water and urine were measured using the national standardized ion selective electrode method. We examined the dose-response effects of low-to-moderate fluoride exposure on dental fluorosis (DF) and intelligence quotient (IQ), and evaluated the potential relationships between DF grades and intelligence levels using piecewise linear regression and multiple logistic regression, respectively.

RESULTS

The adjusted odds ratios (ORs) of DF were 2.24 (95% confidence interval [CI]: 2.02 to 2.48) for every 0.1 mg/L increment in the water fluoride concentration in the range of 0.80 to 1.50 mg/L, and 2.61 (95% CI: 2.32 to 2.93) for every 0.5 mg/L increment in the urinary fluoride level up to 1.80 mg/L. Every 0.5 mg/L increment in the water fluoride level was associated with a reduction of 4.29 in the IQ score (95% CI: -8.09 to -0.48) in the range of 3.40 to 3.90 mg/L, and a decreased probability of developing excellent intelligence (IQ ≥ 130, OR = 0.60, 95% CI: 0.47 to 0.77) in the range of 0.20-1.40 mg/L, respectively. Every 0.5 mg/L increment in the urinary fluoride level was related to a decrease of 2.67 in the IQ scores (95% CI: -4.67 to -0.68) between 1.60 mg/L to 2.50 mg/L. Excellent intelligence decreased by 51% in children with higher urinary fluoride, and by 30% with each degree increment of DF.

CONCLUSIONS

Our study suggests threshold and saturation effects of moderately excessive fluoride exposure on DF and intelligence loss in children, and a potential association between DF and the loss of excellent intelligence.

Effect of S. Mutans and S. Sanguinis on Growth and Adhesion of P. Gingivalis and Their Ability to Adhere to Different Dental Materials

Background

Caries and periodontal diseases are caused by the biofilm formed by caries- and periodontal disease-related bacteria. Specific biofilms could be formed on different filling materials in oral cavity. Thus, to explore the inhibition effect of restorative filling materials on biofilm formation is of great significance in the treatment of caries and periodontal disease.

Material/Methods

The supernatants of S. mutans, S. sanguinis, and P. gingivalis suspension were combined with BHI broth. After 24 h, the live P. gingivalis number was calculated by colony counting and the biofilm was monitored by fluorescence microscopy. To test the adhesive ability of S. mutans and S. sanguinis on different dental materials, the biofilm was formed on different dental materials and then the bacterial number was calculated by using a Spectramax 250 microplate reader at OD 550, and the adhesive ability of S. mutans and S. sanguinis on different dental materials was analyzed by scanning electron microscopy.

Results

The growth and biofilm formation of P. gingivalis was significantly inhibited by S. mutans and S. sanguinis supernatants (P<0.05). All groups except the zinc phosphate cement group (B) exerted a strong inhibitory effect on the biofilm formation of S. mutans and S. sanguinis (P<0.05).

Conclusions

The supernatants of S. mutans and S. sanguinis significantly inhibited the growth and biofilm formation of P. gingivalis, and the adhesive ability of S. mutans and S. sanguinis are different on different dental materials. These results provide useful information on dental caries, periodontal disease, and dental materials.