Tag Archives: fluoridation

Superficial assessment of fluoridation pros and cons

Aoun A, Darwiche F, Al Hayek S, Doumit J. The Fluoride Debate: The Pros and Cons of Fluoridation. Preventive nutrition and food science. 2018 Sep;23(3):171-180. doi: 10.3746/pnf.2018.23.3.171.

Fluoride is one of the most abundant elements found in nature. Water is the major dietary source of fluoride. The only known association with low fluoride intake is the risk of dental caries. Initially, fluoride was considered beneficial when given systemically during tooth development, but later research has shown the importance and the advantages of its topical effects in the prevention or treatment of dental caries and tooth decay. Water fluoridation was once heralded as one of the best public health achievements in the twentieth century. Since this practice is not feasible or cost effective in many regions, especially rural areas, researchers and policy makers have explored other methods of introducing fluoride to the general population such as adding fluoride to milk and table salt. Lately, major concerns about excessive fluoride intake and related toxicity were raised worldwide, leading several countries to ban fluoridation. Health-care professionals and the public need guidance regarding the debate around fluoridation. This paper reviews the different aspects of fluoridation, their effectiveness in dental caries prevention and their risks. It was performed in the PubMed and the Google Scholar databases in January 2018 without limitation as to the publication period.

Fluoride exposure for pregnant women, Canada

Till C, Green R, Grundy JG, Hornung R, Neufeld R, Martinez-Mier EA, Ayotte P, Muckle G, Lanphear B. Community Water Fluoridation and Urinary Fluoride Concentrations in a National Sample of Pregnant Women in Canada. Environmental health perspectives. 2018 Oct;126(10):107001. doi: 10.1289/EHP3546.

BACKGROUND: Fluoride exposures have not been established for pregnant women who live in regions with and without community water fluoridation.

OBJECTIVE: Our aim was to measure urinary fluoride levels during pregnancy. We also assessed the contribution of drinking-water and tea consumption habits to maternal urinary fluoride (MUF) concentrations and evaluated the impact of various dilution correction standards, including adjustment for urinary creatinine and specific gravity (SG).

METHODS: We measured MUF concentrations in spot samples collected in each trimester of pregnancy from 1,566 pregnant women in the Maternal-Infant Research on Environmental Chemicals cohort. We calculated intraclass correlation coefficients (ICCs) to assess variability in MUF concentrations across pregnancy. We used regression analyses to estimate associations between MUF levels, tea consumption, and water fluoride concentrations as measured by water treatment plants.

RESULTS: Creatinine-adjusted MUF values  were almost two times higher for pregnant women living in fluoridated regions  compared with nonfluoridated regions. MUF values tended to increase over the course of pregnancy using both unadjusted values and adjusted values. Reproducibility of the unadjusted and adjusted MUF values was modest . The municipal water fluoride level was positively associated with creatinine-adjusted MUF, accounting for 24% of the variance after controlling for covariates. Higher MUF concentrations correlated with numbers of cups of black but not green tea. Urinary creatinine and SG correction methods were highly correlated and were interchangeable in models examining predictors of MUF.

CONCLUSION: Community water fluoridation is a major source of fluoride exposure for pregnant women living in Canada. Urinary dilution correction with creatinine and SG were shown to be interchangeable for our sample of pregnant women.

Recent study attempts to “prop-up” community fluoridation advocacy

Spencer AJ, Do LG, Ha DH. Contemporary evidence on the effectiveness of water fluoridation in the prevention of childhood caries. Community Dent Oral Epidemiol. 2018 Aug;46(4):407-415. doi: 10.1111/cdoe.12384. 

BACKGROUND: Water fluoridation’s effectiveness has been reaffirmed by systematic reviews. However, most of the included nonrandomised controlled before and after studies were conducted pre-1975. Opportunity for such studies is limited in a steady state of community fluoridation programmes. As an alternative for evidence to support or refute the effectiveness of water fluoridation, this study used data from a recent national child oral health study to examine associations between lifetime exposure to fluoridated water (%LEFW) and childhood caries.

METHODS: A population-based study of child oral health in Australia was conducted in 2012-2014, using complex sampling and weighting procedures. Parents provided detailed household information and children underwent oral epidemiological examination by trained examiners. Residential history from birth was used to calculate %LEFW. Caries prevalence (dmfs/DMFS>0) and experience (dmfs/DMFS) in both primary (age 5-8) and permanent dentitions (age 9-14) were estimated. Socioeconomic factors that were significantly different by %LEFW were then used as covariates in multivariable log-Poisson regression models for each caries outcome by %LEFW.

RESULTS: A total of 24 664 children had complete data. Caries prevalence and experience were higher among 5-8-year-old children with lower %LEFW (46.9%; 4.27 surfaces) than those with 100%LEFW (31.5%; 1.98 surfaces) and for the 9-14-year-old children with lower %LEFW (37.0%; 1.34 surfaces) than those with 100%LEFW (25.0%; 0.67 surfaces). In the multivariable models, the prevalence ratios for primary and permanent caries were significant for the two lower exposure groups against the 100%LEFW group. Similarly, the mean ratios for primary dmfs were significant for all three lower exposure groups and for permanent DMFS were significant for the two lower exposure groups against the 100%LEFW group. Mean ratios for the 0%LEFW compared to the 100%LEFW group were 2.10 (1.83-2.40) for dmfs and 1.82 (1.57-2.10) for DMFS.

CONCLUSION: Analysis of contemporary data representative of the Australian child population found consistent associations between %LEFW and childhood caries, which persisted when socioeconomic differences were adjusted across exposure groups, supporting the continued effectiveness of water fluoridation.

Fluoridated water may increase dental fluorosis risk in infants

Harriehausen CX, Dosani FZ, Chiquet BT, Barratt MS, Quock RL. Fluoride Intake of Infants from Formula. J Clin Pediatr Dent. 2018 Oct 5. doi: 10.17796/1053-4625-43.1.7.

OBJECTIVE: This study aimed to assess fluoride intake in infants from formula reconstituted with water, with fluorosis risk in mind.

STUDY DESIGN: Data on water source, formula brand/type, volume of formula consumption and infant weight were collected for infants at two-, four-, six-, nine- and twelve-month pediatrician well child visits. Identified formula brands and water types were reconstituted and analyzed for fluoride concentration. Patient body mass and volume consumed/day were used to estimate fluoride intake from reconstituted formula. Descriptive statistics, one-way analysis of variance and chi-square tests were utilized.

RESULTS: All infants consumed formula reconstituted with minimally fluoridated water (0.0- 0.3 ppm). 4.4% of infants exceeded the recommended upper limit (UL) of 0.1mg/kg/day. Although mean daily fluoride consumption significantly differed among all groups, the proportion of infants at each visit milestone that exceeded daily fluoride intake of 0.1mg/kg/day was not statistically significantly different (p>0.05) for any age group. Predicted values calculated with optimally fluoridated water (0.7ppm) resulted in 36.8% of infants exceeding the UL.

CONCLUSIONS: Optimally fluoridated water may increase fluorosis risk for patients younger than six months. Future investigation should include multiple sites and multi-year follow-up to assess actual fluorosis incidence.

Presumption of “safety” drives fluoridation study interpretation

Slade GD, Grider WB, Maas WR, Sanders AE. Water Fluoridation and Dental Caries in U.S. Children and Adolescents. J Dent Res. 2018 Sep;97(10):1122-1128. doi: 10.1177/0022034518774331.

Fluoridation of America’s drinking water was among the great public health achievements of the 20th century. Yet there is a paucity of studies from the past 3 decades investigating its dental health benefits in the U.S. This cross-sectional study sought to evaluate associations between availability of community water fluoridation (CWF) and dental caries experience in the U.S. child and adolescent population. County-level estimates of the percentage of population served by CWF (% CWF) from the Centers for Disease Control and Prevention’s Water Fluoridation Reporting System were merged with dental examination data from 10 y of National Health and Nutrition Examination Surveys (1999 to 2004 and 2011 to 2014). Dental caries experience in the primary dentition (decayed and filled tooth surfaces [dfs]) was calculated for 7,000 children aged 2 to 8 y and in the permanent dentition (decayed, missing, and filled tooth surfaces [DMFS]) for 12,604 children and adolescents aged 6 to 17 y. Linear regression models estimated associations between % CWF and dental caries experience with adjustment for sociodemographic characteristics: age, sex, race/ethnicity, rural-urban location, head-of-household education, and period since last dental visit. Sensitivity analysis excluded counties fluoridated after 1998. In unadjusted analysis, caries experience in the primary dentition was lower in counties with ≥75% CWF (mean dfs = 3.3; 95% confidence limit [CL] = 2.8, 3.7) than in counties with <75% CWF (mean dfs = 4.6; 95% CL = 3.9, 5.4), a prevented fraction of 30% (95% CL = 11, 48). The difference was also statistically significant, although less pronounced, in the permanent dentition: mean DMFS (95% CL) was 2.2 (2.0, 2.4) and 1.9 (1.8, 2.1), respectively, representing a prevented fraction of 12% (95% CL = 1, 23). Statistically significant associations likewise were seen when % CWF was modeled as a continuum, and differences tended to increase in covariate-adjusted analysis and in sensitivity analysis. These findings confirm a substantial caries-preventive benefit of CWF for U.S. children and that the benefit is most pronounced in primary teeth.

Water fluoridation contributes to fluoride overexposure

Patil MM, Lakhkar BB, Patil SS. Curse of Fluorosis. Indian J Pediatr. 2018 Jan 3. doi: 10.1007/s12098-017-2574-z.

Fluoride was identified to have caries preventive properties and was widely used for fluoridation of water since 1940, especially in developed countries. After this there was sudden increase in the use of fluorides in food items and in oral medicinal products like toothpastes and mouth washes. Inadvertent use of above has lead to increase in fluorosis as a public health problem. In many places high fluorides are naturally present in earth crust leading to high water fluoride content increasing the risk of fluorosis. Maintaining a fine balance of fluorides in the body is mandatory for exploiting its advantages. World Health Organization (WHO) has fixed permissible limit of fluorides in water to 1.5 mg/L as a preventive step to contain fluorosis. Fluorosis has three clinical components: Dental, Skeletal and Non-Skeletal Fluorosis. It occurs with increasing level of fluorides in the body. Acute toxicity due to fluorides is also known and occurs as a result of sudden exposure to high levels of fluorides, usually by ingestion. Once fluorosis occurs it is irreversible without any cure. Only symptomatic and supportive management is possible. Hence prevention is the mainstay of management. Prevention is by using alternative sources of water or its de-fluoridation. National Program for Prevention and Control of Fluorosis (NPPCF) was launched in 2008-9 to identify areas with high fluoride content of water, manage the water bodies, screen schools and community for fluorosis and comprehensive management of cases. Improving quality of drinking water as per standards and improving nutritional status of children are also important components of prevention of fluorosis.

Fluoride Effects IQ of 12-14 Year-Old Children, India

Razdan P, Patthi B, Kumar JK, Agnihotri N, Chaudhari P, Prasad M. Effect of Fluoride Concentration in Drinking Water on Intelligence Quotient of 12-14-Year-Old Children in Mathura District: A Cross-Sectional Study. Journal of International Society of Preventive and Community Dentistry. 2017 Sep-Oct;7(5):252-258. doi: 10.4103/jispcd.JISPCD_201_17.

AIMS: The aim was to assess and correlate the influence of the concentration of fluoride in ingested water on the intelligence quotient (IQ) of 12-14-year-old youngsters in Mathura district.

MATERIALS AND METHODS: A total of 219 children were selected, 75 from low F area, 75 medium F area, and 69 from high F area. The concentration of fluoride in the routinely ingested water was estimated using “Ion Selective Electrode method”; then, Raven’s Test was utilized to estimate the IQ of the study participants. Independent t-test, Tukey’s post hoc, Chi-square an analysis of variance tests were used to associate the mean and proportion IQ scores in high-, medium-, and low-fluoride regions along with inter-group significant differences (P ≤ 0.05).

RESULTS: The comparison of IQ score showed that 35 (46.7%) participants from the high fluoride and 10 (13.3%) participants from the medium-fluoride areas had below average IQ. Further, it was noted that the lowest mean marks were obtained by the children in the high-fluoride region (13.9467) followed by those in medium (18.9467) and uppermost in least noted fluoride area (38.6087). However, gender-based intergroup comparison did not produce a significant relation with fluoride (P ≥ 0.05).

CONCLUSION: Concentration of Fluoride in the ingested water was significantly associated with the IQ of children. It has also coined the proportional variability in mental output in accordance to the ingested fluoride level. As two sides of a coin, fluoride cannot be utterly blamed for a lower intelligence in a population; it puts forward a fact that intelligence is a multifactorial variable with a strategic role played by genetics and nutrition to develop cognitive and psychosomatic activities in an individual.