Factors influencing the relationship between fluoride in drinking water and dental fluorosis: a ten-year systematic review and meta-analysis

Abstract

The relationship between naturally fluoridated groundwater and dental fluorosis has received large attention from researchers around the world. Despite recognition that several factors influence this relationship, there is a lack of systematic studies analyzing the heterogeneity of these results. To fill such a gap, this study performs a systematic review and meta-analysis to understand which factors influence this relationship and how. Selected studies were sampled between 2007 and 2017 from Web of Science, PubMed, Google Scholar and Scopus using keywords and Boolean operators. Results of the systematic review show that dental fluorosis affects individuals of all ages, with the highest prevalence below 11, while the impact of other factors (gender, environmental conditions, diet and dental caries) was inconclusive. Meta-regression analysis, based on information collected through systematic review, indicates that both fluoride in drinking water and temperature influence dental fluorosis significantly and that these studies might be affected by publication bias. Findings show that fluoride negatively affects people's health in less developed countries. The conclusions discuss policy tools and technological innovations that could reduce fluoride levels below that of the World Health Organization (WHO) (<1.5 mg/L).

Assessment of fluoride levels during pregnancy and its association with early adverse pregnancy outcomes

“…[ 11 12 13 14 15 ] Because of more than 90% bioavailability, the consumption of excess of fluoride through drinking water is one of the main causes of fluorosis. [ 16 17 ] We examined a group of 600 pregnant women of reproductive age group from lower socioeconomic strata who were regularly exposed to fluoride by means of drinking water with the aim of detecting the early adverse pregnancy outcomes comprising abortions, IUDs, and congenital abnormalities. This study was done in Faridkot district of Punjab, India and on the examination of groundwater and tap water, it was detected that the mean value of the water fluoride content was 2.4 mg/L that is more than the permissible limits.…”

Effect of Fluoride Concentration in Drinking Water on Dental Fluorosis in Southwest Saudi Arabia

“…Fluorine, a natural element, is readily dissolved in water, soil and air, and does not occur on its own in nature but occurs relatively as fluoride [1]. Fluoride is beneficial for humans, however an excess of this ion can produce numerous adverse effects on human health [1,2]. Surface water is usually low in fluoride, with a value lower than 1.5 mg/L, although groundwater can contain an increased level of fluoride depending on geographical situations.…”

“…Surface water is usually low in fluoride, with a value lower than 1.5 mg/L, although groundwater can contain an increased level of fluoride depending on geographical situations. Increased fluoride levels in drinking water above 1.5 mg/L causes a higher risk of dental fluorosis, though increasingly greater concentrations can lead to the risk of skeletal fluorosis as well [2].…”

“…In the Kingdom of Saudi Arabia (KSA), tooth decay is an important public health issue, affecting the primary dentition of around 95%of kids aged 3-7 years, around 91% youngsters aged between 12 and 19 years, and 98% of adults aged between 30 and 45 years [3].Especially, in the eastern province of KSA, the overall frequency of dental caries among children aged between 6 and 9 years and10 and 12 years is 73% and 68%, respectively [3].Water fluoridation is considered as a cost-effective measure for caries-prevention in individuals of moderate to high caries risk. In addition, it has a strong safety profile, with the only side effect being a low risk of very mild fluorosis (~2%), which itself may not essentially be due to the exposure to increasing levels of fluoride alone [2,5,6].A study showed that 75% of public water supplied in the central province cities of Riyadh and Qassim has fluoride levels between 0 and 6 ppm [9].One more study performed in three cities of the western province of Saudi Arabia discovered varying fluoride levels, ranging from0.3 to 2.5 ppm, depending on the water supply source [3]. However, the US Department of Health and human services suggests that the optimal water fluoride level for humans with negligible risk is 0.7 ppm [10].…”

Prevalence of Dental Fluorosis among Southern Jordanian Population

“…Fluorine is a natural element that has been observed to exist in many mineral forms. Geographic activity such as weather and volcanoes may cause increased its quantity within drinkable water [ 1 ]. In the human body, fluorine plays a vital part when it comes to the mineralization of teeth, bones, and other hard tissues.…”