BOH Agenda 032520 - Laserfiche WebLink

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The studies in Table 2 include time -series cross-sectional studies in communities that either added or removed fluoride from drinking water . Others used a single -cross sectional study design , focusing on the association between exposure to fluoridation and the extent of income - inequalities in caries . One study warrants further emphasis because of its timeliness in being the first study in 30 years to investigate water fluoridation and dental caries in the U . S . child population . The cross-sectional study used data from five cycles of the National Health and Nutrition Examination Survey ( NHANES ) conducted between 1999 and 2014 . Dental caries experience of 16, 718 sampled children was measured by trained examiners who recorded dfs and DMFS indices . Sociodemographic characteristics and dental health behaviors were reported by parents/guardians during the NHANES interview . Information about fluoridation in each child ' s county- of- residence was obtained from the Water Fluoridation Reporting System ( WFRS ) . This database contains information about fluoride concentration and population size served by each of approximately 54,000 U . S . public water systems . The first publication from the study compared caries experience according to the percentage of county population served by a fluoridated public water system . For descriptive purposes, mean levels of caries experience were compared between two groups classified according to the percentage of county population served by public water containing >_0 . 7 mg/ L F : < 75 % or >_75 % . Separate analysis used a linear regression model to estimate a " dose- response" gradient between caries experience and the proportion of the county' s population that was fluoridated ( modeled as a continuous variable , ranging from 0 to 1 ) . The rationale was that the dichotomous classification of fluoridation ( < 75 % or >_ 75 % ) provides an estimate of the association at a pragmatic public health level , recognizing that many counties have some fraction of the population that does not use a public water system , making 100% fluoridation unattainable . In contrast, the continuous measure of fluoridation estimates the likely impact of fluoridation in situations where 100 % coverage is attainable . For primary dentition caries, mean dfs was 4 . 6 in counties with <75 % fluoridation compared to 3 . 3 in counties with >_75 % fluoridation and the covariate - adjusted group difference between the two groups was 1 . 39 ( i . e . , after adjusting for socio -demographics and dental behaviors ) . Using the continuous measure of county- level fluoridation , the adjusted difference associated with 0% versus 100% fluoridation was 2 . 1 . In the permanent dentition , mean DMFS was 2 . 2 and 1 . 9 in < 75 % fluoridation and >_ 75 % fluoridation counties, the fully-adjusted difference was 0 . 25 , while, using continuous measure of fluoridation , the difference between 0% versus 100% fluoridation was 0 . 88 . However, it is more informative to consider those effect estimates for groups of children , rather than for individuals . To that end , Table 3 summarizes the same effect estimates for an average group of 30 children in the U . S . population ( i . e . , the approximate number of children in a school classroom ) . Based on the contrast of 0 % with 100%, fluoridation is associated with 62 fewer cavities in primary teeth per thirty 2 - 8 year olds, and 26 fewer cavities in permanent teeth per thirty 6 - 17 year olds (Table 3 ) .