Fluoride concentration of drinking water and dental fluorosis: A systematic review and meta-analysis in Iran

Recently, a number of studies have investigated the impact of fluoride concentration of drinking water on dental fluorosis. These Studies should be reviewed to provide a new outlook on the analysis of the causes and effects of dental fluorosis in specific regions. The objective of this study was to systematically review the fluoride concentration of drinking water and investigate its relation to the frequency of dental fluorosis in Iran.
Materials and Dean’s index was used to classify data, and a meta-analysis was conducted to obtain summary measure with 95% confidence interval (CI). In this regard, Stata/SE 11.1 was employed for data analysis based on random effect models for reporting the results. In this systematic review, Scientific Information Database (SID) and IranMedex databases were searched and studies were included based on specific criteria. Data validity was assessed using the strengthening the reporting of observational studies in epidemiology (STROBE) checklist adapted for cross-sectional study designs. Furthermore, a series of predefined keywords were used, and the combination of these keywords were considered using operators. The inconsistency was examined using the χ2 test at a significance level of 10%. In addition, heterogeneity was quantified across studies using the І2 statistic. The difference between study variance was analyzed based on τ2 statistic.
In the age group of 6–18 years old based on the fluoride level in drinking water and exposure time, there was significant heterogeneity among the studies in all subgroups for determining the frequency of dental fluorosis and assessing the effect of other variables.
The variables, water fluoride exposure time, and any exposure to fluoride are considered as confounding factors. Analyzing the subgroups and examining the heterogeneity showed that the results of the studies in all subgroups cannot be pooled.