June 2, 2017

Measuring the short-term impact of fluoridation cessation on dental caries in Grade 2 children using tooth surface indices (Edmonton – Calgary Comparison) 2016

Abstract

Objectives: To examine the short-term impact of fluoridation cessation on children’s caries experience measured by tooth surfaces. If there is an adverse short-term effect of cessation, it should be apparent when we focus on smooth tooth surfaces, where fluoride is most likely to have an impact for the age group and time frame considered in this study.

Methods: We examined data from population-based samples of school children (Grade 2) in two similar cities in the province of Alberta, Canada: Calgary, where cessation occurred in May 2011 and Edmonton where fluoridation remains in place. We analysed change over time (2004/2005 to 2013/2014) in summary data for primary (defs) and permanent (DMFS) teeth for Calgary and Edmonton, for all tooth surfaces and smooth surfaces only. We also considered, for 2013/2014 only, the exposed subsample defined as lifelong residents who reported usually drinking tap water.

Results: We observed, across the full sample, an increase in primary tooth decay (mean defs – all surfaces and smooth surfaces) in both cities, but the magnitude of the increase was greater in Calgary (F-cessation) than in Edmonton (F-continued). For permanent tooth decay, when focusing on smooth surfaces among those affected (those with DMFS>0), we observed a non-significant trend towards an increase in Calgary (F-cessation) that was not apparent in Edmonton (F-continued). Conclusions: Trends observed for primary teeth were consistent with an adverse effect of fluoridation cessation on children’s tooth decay, 2.5–3 years post-cessation. Trends for permanent teeth hinted at early indication of an adverse effect. It is important that future data collection efforts in the two cities be undertaken, to permit continued monitoring of these trends.

McLaren et al – Community Dentistry and Oral Epidemiology – Edmonton/Calgary Fluoridation Cessation Study 2016

An Unscientific Tale Of Two Cities (The Calgary Edmonton Fluoridation Cessation Study Critique) Feb 19, 2016

 

Public perceptions and scientific evidence for perceived harms/risks of community water fluoridation: An examination of online comments pertaining to fluoridation cessation in Calgary in 2011

Podgorny PC, McLaren L.

Can J Public Health. 2015 Jun 19;106(6):e413-25. doi: 10.17269/cjph.106.5031.

PMID: 26680434

ABSTRACT

OBJECTIVES:

To examine the perceived harms/risks of fluoridation as expressed in online forums relating to cessation and aftermath in Calgary, specifically, 1) which harms/risks are mentioned, 2) for those harms/risks, what kinds of evidence are cited, 3) to what extent is scientific literature cited, and what is its quality, and 4) for a subset of harms/risks, what is known from the broader scientific literature?

METHODS:

Relevant online comments were identified through free-text Internet searches, and those explicitly discussing the harms/risks of water fluoridation were extracted. Types of evidence mentioned were identified, and the scientific papers cited were reviewed. Finally, the broader scientific literature on two of the harms/risks was reviewed and synthesized.

SYNTHESIS:

We identified 17 distinct groups of harms/risks, which spanned human body systems, the environment and non-human organisms. Most often, no evidence was cited. When evidence was cited, types included individuals viewed as authorities and personal experiences. Reference to scientific articles was rare, and those papers (n = 9) had significant methodological concerns. Our review of scientific literature on fluoride and 1) thyroid functioning and 2) phytoplankton revealed some negative effects of fluoride at concentrations exceeding maximum recommended levels (>1.5 ppm).

CONCLUSION:

The findings have implications for communication with the public about fluoridation. First, to the extent that the public consults the scientific literature, it is essential that the methodological limitations of a study, as well as its relevance to community water fluoridation, be widely and promptly communicated. Second, scientific evidence is only one component of why some people support or do not support fluoridation, and communication strategies must accommodate that reality.

http://www.ncbi.nlm.nih.gov/pubmed/26680434

Public perceptions and scientific evidence for perceived harms/risks of community water fluoridation: An examination of online comments pertaining to fluoridation cessation in Calgary in 2011.

Iheozor-Ejiofor Z, Worthington HV, Walsh T, O’Malley L, Clarkson JE, Macey R, Alam R, Tugwell P, Welch V, Glenny A, Water fluoridation to prevent tooth decay, Cochrane Review

Title: Water fluoridation to prevent tooth decay

Published: 18-Jun-2015

Authors: Iheozor-Ejiofor Z, Worthington HV, Walsh T, O’Malley L, Clarkson JE, Macey R, Alam R, Tugwell P, Welch V, Glenny A

Primary Review Group: Oral Health Group

Background

Tooth decay is a significant problem worldwide affecting the majority of adults and children. Although levels of tooth decay have been decreasing in some communities (levels vary both between and within countries), generally children from poorer backgrounds (measured by income, education and employment) have greater levels of tooth decay.

Untreated tooth decay causes progressive destruction of teeth which is often accompanied by severe pain. This may lead to teeth having to be removed under local or general anaesthetic.

Fluoride is a mineral that prevents tooth decay. It occurs naturally in the soil, water and atmosphere at varying levels worldwide. Water can be artificially fluoridated (also known as community water fluoridation) through the controlled addition of a fluoride compound to a public water supply. Fluoridation is set at the ‘optimum level’, considered to be around 1 part per million (ppm).

Fluoride is also available in most toothpastes and can be provided as an extra preventive measure through products like mouth rinses, varnishes and gels.

An unwanted effect of fluoride use is the marking of permanent teeth (dental fluorosis) that is caused when young children, whose permanent teeth are developing, swallow excessive fluoride. This can range from mild white patches on the teeth to severe mottling with brown staining.

Review question

This review was conducted to assess the effects of water fluoridation (artificial or natural) for the prevention of tooth decay. It also evaluates the effects of fluoride in water on the white or brown marks on the tooth enamel that can be caused by too much fluoride (dental fluorosis).

Study characteristics

Researchers from the Cochrane Oral Health Group reviewed the evidence – up to 19 February 2015 – for the effect of water fluoridation. They identified 155 studies in which children receiving fluoridated water (either natural or artificial) were compared with those receiving water with very low or no fluoride. Twenty studies examined tooth decay, most of which (71%) were conducted prior to 1975. A further 135 studies examined dental fluorosis.

Key results

Data suggest that the introduction of water fluoridation resulted in a 35% reduction in decayed, missing or filled baby teeth and a 26% reduction in decayed, missing or filled permanent teeth. It also increased the percentage of children with no decay by 15%. Although these results indicate that water fluoridation is effective at reducing levels of tooth decay in children’s baby and permanent teeth, the applicability of the results to current lifestyles is unclear because the majority of the studies were conducted before fluoride toothpastes and the other preventative measures were widely used in many communities around the world.

There was insufficient information available to find out whether the introduction of a water fluoridation programme changed existing differences in tooth decay across socioeconomic groups.

There was insufficient information available to understand the effect of stopping water fluoridation programmes on tooth decay.

No studies met the review’s inclusion criteria that investigated the effectiveness of water fluoridation for preventing tooth decay in adults, rather than children.

The researchers calculated that, in areas with a fluoride level of 0.7 ppm in the water, approximately 12% of the people evaluated had fluorosis that could cause concern about their appearance.

Quality of the evidence

The review authors assessed each study included in the review for risk of bias (by examining the quality of the methods used and how thoroughly the results were reported) to determine the extent to which the results reported are likely to be reliable. This showed that over 97% of the 155 studies were at a high risk of bias, which reduces the overall quality of the results. There was also substantial variation between studies in terms of their results.

Our confidence in the size of effect shown for the prevention of tooth decay is limited due to the high risk of bias in the included studies and the fact that most of the studies were conducted before the use of fluoride toothpaste became widespread.

Our confidence in the evidence relating to dental fluorosis is also limited due to the high risk of bias and variation in the studies’ results.

Read the full abstract below

Authors’ conclusions:

There is very little contemporary evidence, meeting the review’s inclusion criteria, that has evaluated the effectiveness of water fluoridation for the prevention of caries.

The available data come predominantly from studies conducted prior to 1975, and indicate that water fluoridation is effective at reducing caries levels in both deciduous and permanent dentition in children. Our confidence in the size of the effect estimates is limited by the observational nature of the study designs, the high risk of bias within the studies and, importantly, the applicability of the evidence to current lifestyles. The decision to implement a water fluoridation programme relies upon an understanding of the population’s oral health behaviour (e.g. use of fluoride toothpaste), the availability and uptake of other caries prevention strategies, their diet and consumption of tap water and the movement/migration of the population. There is insufficient evidence to determine whether water fluoridation results in a change in disparities in caries levels across SES. We did not identify any evidence, meeting the review’s inclusion criteria, to determine the effectiveness of water fluoridation for preventing caries in adults.

There is insufficient information to determine the effect on caries levels of stopping water fluoridation programmes.

There is a significant association between dental fluorosis (of aesthetic concern or all levels of dental fluorosis) and fluoride level. The evidence is limited due to high risk of bias within the studies and substantial between-study variation.

Background: 

Dental caries is a major public health problem in most industrialised countries, affecting 60% to 90% of school children. Community water fluoridation was initiated in the USA in 1945 and is currently practised in about 25 countries around the world; health authorities consider it to be a key strategy for preventing dental caries. Given the continued interest in this topic from health professionals, policy makers and the public, it is important to update and maintain a systematic review that reflects contemporary evidence.

Objectives: 

To evaluate the effects of water fluoridation (artificial or natural) on the prevention of dental caries.

To evaluate the effects of water fluoridation (artificial or natural) on dental fluorosis.

Search strategy:

We searched the following electronic databases: The Cochrane Oral Health Group’s Trials Register (to 19 February 2015); The Cochrane Central Register of Controlled Trials (CENTRAL; Issue 1, 2015); MEDLINE via OVID (1946 to 19 February 2015); EMBASE via OVID (1980 to 19 February 2015); Proquest (to 19 February 2015); Web of Science Conference Proceedings (1990 to 19 February 2015); ZETOC Conference Proceedings (1993 to 19 February 2015). We searched the US National Institutes of Health Trials Registry (ClinicalTrials.gov) and the World Health Organization’s WHO International Clinical Trials Registry Platform for ongoing trials. There were no restrictions on language of publication or publication status in the searches of the electronic databases.

Selection criteria: 

For caries data, we included only prospective studies with a concurrent control that compared at least two populations – one receiving fluoridated water and the other non-fluoridated water – with outcome(s) evaluated at at least two points in time. For the assessment of fluorosis, we included any type of study design, with concurrent control, that compared populations exposed to different water fluoride concentrations. We included populations of all ages that received fluoridated water (naturally or artificially fluoridated) or non-fluoridated water.

Data collection and analysis: 

We used an adaptation of the Cochrane ‘Risk of bias’ tool to assess risk of bias in the included studies.

We included the following caries indices in the analyses: decayed, missing and filled teeth (dmft (deciduous dentition) and DMFT (permanent dentition)), and proportion caries free in both dentitions. For dmft and DMFT analyses we calculated the difference in mean change scores between the fluoridated and control groups. For the proportion caries free we calculated the difference in the proportion caries free between the fluoridated and control groups.

For fluorosis data we calculated the log odds and presented them as probabilities for interpretation.

Main results: 

A total of 155 studies met the inclusion criteria; 107 studies provided sufficient data for quantitative synthesis.

The results from the caries severity data indicate that the initiation of water fluoridation results in reductions in dmft of 1.81 (95% CI 1.31 to 2.31; 9 studies at high risk of bias, 44,268 participants) and in DMFT of 1.16 (95% CI 0.72 to 1.61; 10 studies at high risk of bias, 78,764 participants). This translates to a 35% reduction in dmft and a 26% reduction in DMFT compared to the median control group mean values. There were also increases in the percentage of caries free children of 15% (95% CI 11% to 19%; 10 studies, 39,966 participants) in deciduous dentition and 14% (95% CI 5% to 23%; 8 studies, 53,538 participants) in permanent dentition. The majority of studies (71%) were conducted prior to 1975 and the widespread introduction of the use of fluoride toothpaste.

There is insufficient information to determine whether initiation of a water fluoridation programme results in a change in disparities in caries across socioeconomic status (SES) levels.

There is insufficient information to determine the effect of stopping water fluoridation programmes on caries levels.

No studies that aimed to determine the effectiveness of water fluoridation for preventing caries in adults met the review’s inclusion criteria.

With regard to dental fluorosis, we estimated that for a fluoride level of 0.7 ppm the percentage of participants with fluorosis of aesthetic concern was approximately 12% (95% CI 8% to 17%; 40 studies, 59,630 participants). This increases to 40% (95% CI 35% to 44%) when considering fluorosis of any level (detected under highly controlled, clinical conditions; 90 studies, 180,530 participants). Over 97% of the studies were at high risk of bias and there was substantial between-study variation.

http://www.cochrane.org/CD010856/ORAL_water-fluoridation-to-prevent-tooth-decay

http://onlinelibrary.wiley.com/doi/10.1002/14651858.CD010856.pub2/abstract;jsessionid=C7F1767522BDF6E33665E86AEEEACE98.f03t02

Read the FULL RESEARCH PAPER here.

What is Cochrane evidence and how can it help you?

About Cochrane

Malin and Till, Exposure to fluoridated water and attention deficit hyperactivity disorder prevalence among children and adolescents in the United States: an ecological association, Environmental Health

ABSTRACT (provisional)

Background Epidemiological and animal-based studies have suggested that prenatal and postnatal fluoride exposure has adverse effects on neurodevelopment. The aim of this study was to examine the relationship between exposure to fluoridated water and Attention-Deficit Hyperactivity Disorder (ADHD) prevalence among children and adolescents in the United States. Methods Data on ADHD prevalence among 4-17 year olds collected in 2003, 2007 and 2011 as part of the National Survey of Children’s Health, and state water fluoridation prevalence from the Centers for Disease Control and Prevention (CDC) collected between 1992 and 2008 were utilized. Results State prevalence of artificial water fluoridation in 1992 significantly positively predicted state prevalence of ADHD in 2003, 2007 and 2011, even after controlling for socioeconomic status. A multivariate regression analysis showed that after socioeconomic status was controlled each 1% increase in artificial fluoridation prevalence in 1992 was associated with approximately 67,000 to 131,000 additional ADHD diagnoses from 2003 to 2011. Overall state water fluoridation prevalence (not distinguishing between fluoridation types) was also significantly positively correlated with state prevalence of ADHD for all but one year examined. Conclusions Parents reported higher rates of medically-diagnosed ADHD in their children in states in which a greater proportion of people receive fluoridated water from public water supplies. The relationship between fluoride exposure and ADHD warrants future study.

The complete article is available as a provisional PDF. The fully formatted PDF and HTML versions are in production.

http://cof-cof.ca/wp-content/uploads/2015/02/Malin-Till-Exposure-to-fluoridated-water-and-attention-deficit-hyperactivity-disorder-prevalence-among-children-and-adolescents-in-the-United-States-an-ecological-association-Environmental-Health-Feb-27-2015.pdf

http://www.ehjournal.net/content/14/1/17/abstract

Peckham, Lowery and Spencer, Are fluoride levels in drinking water associated with hypothyroidism prevalence in England? A large observational study of GP practice data and fluoride levels in drinking water

ABSTRACT

Background
While previous research has suggested that there is an association between fluoride ingestion and the incidence of hypothyroidism, few population level studies have been undertaken. In England, approximately 10% of the population live in areas with community fluoridation schemes and hypothyroidism prevalence can be assessed from general practice data. This observational study examines the association between levels of fluoride in water supplies with practice level hypothyroidism prevalence.

Methods
We used a cross-sectional study design using secondary data to develop binary logistic regression models of predictive factors for hypothyroidism prevalence at practice level using 2012 data on fluoride levels in drinking water, 2012/2013 Quality and Outcomes Framework (QOF) diagnosed hypothyroidism prevalence data, 2013 General Practitioner registered patient numbers and 2012 practice level Index of Multiple Deprivation scores.

Findings
We found that higher levels of fluoride in drinking water provide a useful contribution for predicting prevalence of hypothyroidism. We found that practices located in the West Midlands (a wholly fluoridated area) are nearly twice as likely to report high hypothyroidism prevalence in comparison to Greater Manchester (non-fluoridated area).

Interpretation
In many areas of the world, hypothyroidism is a major health concern and in addition to other factors — such as iodine deficiency — fluoride exposure should be considered as a contributing factor. The findings of the study raise particular concerns about the validity of community fluoridation as a safe public health measure.

http://cof-cof.ca/wp-content/uploads/2015/03/Peckham-et-al-Are-Fluoride-Levels-In-Drinking-Water-Associated-With-Hypothyroidism-Prevalence-In-England-18-Jan-2015.pdf

Ko and Thiessen, A Critique of Recent Economic Evaluations of Community Water Fluoridation, International Journal of Occupational and Environmental Health

ABSTRACT

Background:  Although community water fluoridation (CWF) results in a range of potential contaminant exposures, little attention has been given to many of the possible impacts. A central argument for CWF is its
cost-effectiveness. The U.S. Government states that $1 spent on CWF saves $38 in dental treatment costs.

Objective:  To examine the reported cost-effectiveness of CWF.

Methods:  Methods and underlying data from the primary U.S. economic evaluation of CWF are analyzed and corrected calculations are described. Other recent economic evaluations are also examined.

Results:  Recent economic evaluations of CWF contain defective estimations of both costs and benefits.  Incorrect handling of dental treatment costs and flawed estimates of effectiveness lead to overestimated
benefits. The real-world costs to water treatment plants and communities are not reflected.

Conclusions:  Minimal correction reduced the savings to $3 per person per year (PPPY) for a best-case scenario, but this savings is eliminated by the estimated cost of treating dental fluorosis.

Ko and Thiessen, A Critique of Recent Economic Evaluations of Community Water Fluoridation, International Journal of Occupational and Environmental Health, Dec-2014

http://www.maneyonline.com/doi/pdfplus/10.1179/2049396714Y.0000000093

Toronto Total Health Show 07-April-2013, Dr. Hardy Limeback Presentation – Is There a Natural Way to Fight Dental Decay

Limeback - Natural Way To Fight Dental Decay 450 x 335

Toronto Total Health Show 07-April-2013, Dr. Hardy Limeback Presentation – Is There A Natural Way To Fight Dental Decay

 

Zhou et al, Environmental Fluoride Exposure and Reproductive Hormones in Males Living in Endemic Fluorosis Villages in China

ABSTRACT

Objective:  To explore the influence of high fluoride exposure on reproductive hormones in male living in endemic fluorosis villages in China.

Methods:  A cross sectional study was conducted in Tongxu county in Henan Province, China. Endemic fluorosis villages and control villages were selected by random sampling according to fluoride concentration in drinking water and the prevalence of endemic fluorosis. Local male residents aged from 18 to 50 years old who were born and grew up in the investigated villages were recruited as subjects by cluster sampling. Fasting blood and urine samples were collected. The serum level of GnRH was detected using ELISA. The serum level of luteinizing hormone (LH), follicle-stimulating hormone (FSH), estradiol (E2), and testosterone (T) were determined by chemiluminesence immunoassay (CLIA).

Results:  The serum levels of FSH were 7.82 mlU/ml, 10.20 mIU/ml and 9.57 mIU/ml in male from defluoridation villages (DFPG), high fluoride villages (HFG) and control villages (CG) respectively. FSH level in male from DFPG was significant lower than that from HFG and CG (P<0.05). The serum levels of E2 were 33.67 ng/mL, 29.17 ng/mL and 28.99 ng/mL in DPFG, HFG and CG respectively. E2 level in male from DFPG was significant higher than that from HFG and CG (P<0.05). Serum levels of E2 in CG were associated with LH (r=0.343, P=0.000), age (r=0.195, P=0.015), and inversely associated with serum FSH (r=-0.237, P=0.003), whereas this correlation was not observed for serum E2 level in DFPG and HFG.

Conclusion:  Long-term fluoride exposure in drinking water may influence the reproductive hormones in males living in endemic fluorosis villages.

Zhou et al, Environmental Fluoride Exposure And Reproductive Hormones In Males Living In Endemic Fluorosis Villages In China, Life Science Journal, Jul-2012

Choi, Sun, Zhang & Grandjean, Developmental Fluoride Neurotoxicity – A Systematic Review and Meta-Analysis

ABSTRACT

Background: Although fluoride may cause neurotoxicity in animal models and acute fluoride poisoning causes neurotoxicity in adults, very little is known of its effects on children’s neurodevelopment.

Objective: We performed a systematic review and meta-analysis of published studies to investigate the effects of increased fluoride exposure and delayed neurobehavioral development.

Methods: We searched the MEDLINE, EMBASE, Water Resources Abstracts, and TOXNET databases through 2011 for eligible studies. We also searched the China National Knowledge Infrastructure (CNKI) database, as many studies on fluoride neurotoxicity have been published in Chinese journals only. In total, we identified 27 eligible epidemiological studies with high and reference exposures, endpoints of IQ scores or related cognitive function measures with means and variances for the two exposure groups. We estimated the standardized mean difference (SMD) between exposed and reference groups across all studies using random effects models. We conducted sensitivity analyses restricted to studies using the same outcome assessment and having drinking water fluoride as the only exposure. Cochran test for heterogeneity between studies, Begg’s funnel plot and Egger test to assess publication bias were performed. Metaregressions to explore sources of variation in mean differences among the studies were conducted.

Results: The standardized weighted mean difference in IQ score between exposed and reference populations was -0.45 (95% CI -0.56 to -0.35) using a random-effects model. Thus, children in high fluoride areas had significantly lower IQ scores than those who lived in low fluoride areas. Subgroup and sensitivity analyses also indicated inverse associations, although the substantial heterogeneity did not appear to decrease.

Conclusions: The results support the possibility of an adverse effect of high fluoride exposure on children’s neurodevelopment. Future research should include detailed individual-level information on prenatal exposure, neurobehavioral performance, and covariates for adjustment.

http://cof-cof.ca/wp-content/uploads/2015/03/Choi-Sun-Zhang-Grandjean-Developmental-Fluoride-Neurotoxicity-A-Systematic-Review-and-Meta-Analysis-10-Oct-2012.pdf

The study was published online in Environmental Health Perspectives on July 20, 2012.

Choi et al, Developmental Fluoride Neurotoxicity – A Systematic Review and Meta-Analysis, Environmental Health Perspectives 20-Jul-2012

Supplemental Material – Choi et al, Developmental Fluoride Neurotoxicity – A Systematic Review and Meta-Analysis, Environmental Health Perspectives 20-Jul-2012

Periodontal Disease and Atherosclerotic Vascular Disease – Does the Evidence Support an Independent Association, A Scientific Statement from the American Heart Association

ABSTRACT

A link between oral health and cardiovascular disease has been proposed for more than a century. Recently, concern about possible links between periodontal disease (PD) and atherosclerotic vascular disease (ASVD) has intensified and is driving an active field of investigation into possible association and causality. The 2 disorders share several common risk factors, including cigarette smoking, age, and diabetes mellitus. Patients and providers are increasingly presented with claims that PD treatment strategies offer ASVD protection; these claims are often endorsed by professional and industrial stakeholders. The focus of this review is to assess whether available data support an independent association between ASVD and PD and whether PD treatment might modify ASVD risks or outcomes. It also presents mechanistic details of both PD and ASVD relevant to this topic. The correlation of PD with ASVD outcomes and surrogate markers is discussed, as well as the correlation of response to PD therapy with ASVD event rates. Methodological issues that complicate studies of this association are outlined, with an emphasis on the terms and metrics that would be applicable in future studies. Observational studies to date support an association between PD and ASVD independent of known confounders. They do not, however, support a causative relationship. Although periodontal interventions result in a reduction in systemic inflammation and endothelial dysfunction in short-term studies, there is no evidence that they prevent ASVD or modify its outcomes.

Periodontal Disease And Atherosclerotic Vascular Disease – Does The Evidence Support An Independent Association, A Scientific Statement From The American Heart Association 18-Apr-2012