Tag Archives: fluoridation

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.

Early Concerns about Water Fluoridation Ignored Resulting in a Presumption of Safety

Adding fluoride to drinking water is the sacred cow for advocates within the dental community (e.g. here). Much has been written on this topic and many articles can be found on this blog and other sites. The presumption of safety was imposed and institutionalized early on. But evidence is not neutral. The assumptions of the interpreter determine what conclusions are reached based on the evidence. The historical presumption of safety (it is safe until proven that it is not) has result the same conclusion of safety by every government or association panel evaluation of fluoridation. But evidence-based hazards and risks have been completely ignored or downplayed from the beginning of the practice. Indeed, organizations simply repeat the same song typically endorsing each others endorsement. The absence of dead bodies in the street or repetitive results from ecological studies interpreted using particular statistical tests is simply not sufficient justification for continuing the practice. But it continues nevertheless…

C Carstairs Debating Water Fluoridation Before Dr. Strangelove. American Journal of Public Health. 2015;105:1559–1569. doi:10.2105/AJPH.2015.302660.

In the 1930s, scientists learned that small amounts of fluoride naturally occurring in water could protect teeth from decay, and the idea of artificially adding fluoride to public water supplies to achieve the same effect arose. In the 1940s and early 1950s, a number of studies were completed to determine whether fluoride could have harmful effects. The research suggested that the possibility of harm was small. In the early 1950s, Canadian and US medical, dental, and public health bodies all endorsed water fluoridation. I argue in this article that some early concerns about the toxicity of fluoride were put aside as evidence regarding the effectiveness and safety of water fluoridation mounted and as the opposition was taken over by people with little standing in the scientific, medical, and dental communities. The sense of optimism that infused postwar science and the desire of dentists to have a magic bullet that could wipe out tooth decay also affected the scientific debate. 

Hydrofluosilicic acid study avoids the key issue

This study looks at arsenic as an impurity in a chemical used to add fluoride to drinking water. The NSF/ANSI standard 60 addresses these questions and making such studies generally unnecessary. What is overlooked is the obvious question is whether adding fluoride to water is a benefit at all. Indeed, it has become a sacred cow enabling advocates to feel good about themselves preventing dental decay without actually having much of a benefit.

Peterson E, Shapiro H, Li Y, Minnery JG, Copes R. Arsenic from community water fluoridation: quantifying the effect. Journal of water and health. 2016 Apr;14(2):236-42. doi: 10.2166/wh.2015.105.

Community water fluoridation is a WHO recommended strategy to prevent dental carries. One debated concern is that hydrofluorosilicic acid, used to fluoridate water, contains arsenic and poses a health risk. This study was undertaken to determine if fluoridation contributes to arsenic in drinking water, to estimate the amount of additional arsenic associated with fluoridation, and compare this to the National Sanitation Foundation/American National Standards Institute (NSF/ANSI) standard and estimates from other researchers. Using surveillance data from Ontario drinking water systems, mixed effects linear regression was performed to examine the effect of fluoridation status on the difference in arsenic concentration between raw water and treated water samples. On average, drinking water treatment was found to reduce arsenic levels in water in both fluoridated and non-fluoridated systems by 0.2 μg/L. However, fluoridated systems were associated with an additional 0.078 μg/L (95% CI 0.021, 0.136) of arsenic in water when compared to non-fluoridated systems (P = 0.008) while controlling for raw water arsenic concentrations, types of treatment processes, and source water type. Our estimate is consistent with concentrations expected from other research and is less than 10% of the NSF/ANSI standard of 1 μg/L arsenic in water. This study provides further information to inform decision-making regarding community water fluoridation.