Introduction: Dental fluorosis has been assessed only 3 times in nationally representative oral health surveys in the United States. The first survey was conducted by the National Institute of Dental Research from 1986 to 1987. Subsequently, the National Health and Nutrition Examination Survey (NHANES) conducted fluorosis assessments from 1999 to 2004 and more recently from 2011 to 2012. A large increase in prevalence and severity of fluorosis occurred between the 1986-1987 and 1999-2004 surveys.
Objectives: To determine whether the trend of increasing fluorosis continued in the 2011-2012 survey.
Methods: We analyzed publicly available data from the 2011-2012 NHANES, calculating fluorosis prevalence and severity using 3 measures: person-level Dean's Index score, total prevalence of those with Dean's Index of very mild degree and greater, and Dean's Community Fluorosis Index. We examined these fluorosis measures by several sociodemographic factors and compared results with the 2 previous surveys. Analyses accounted for the complex design of the surveys to provide nationally representative estimates.
Results: Large increases in severity and prevalence were found in the 2011-2012 NHANES as compared with the previous surveys, for all sociodemographic categories. For ages 12 to 15 y-an age range displaying fluorosis most clearly-total prevalence increased from 22% to 41% to 65% in the 1986-1987, 1999-2004, and 2011-2012 surveys, respectively. The rate of combined moderate and severe degrees increased the most, from 1.2% to 3.7% to 30.4%. The Community Fluorosis Index increased from 0.44 to 0.67 to 1.47. No clear differences were found in fluorosis rates among categories for most of the sociodemographic variables in the 2011-2012 survey.
Conclusion: Large increases in fluorosis prevalence and severity occurred. We considered several possible spurious explanations for these increases but largely ruled them out based on counterevidence. We suggest several possible real explanations for the increases.
Knowledge transfer statement: The results of this study greatly increase the evidence base indicating that objectionable dental fluorosis has increased in the United States. Dental fluorosis is an undesirable side effect of too much fluoride ingestion during the early years of life. Policy makers and professionals can use the presented evidence to weigh the risks and benefits of water fluoridation and early exposure to fluoridated toothpaste.
Keywords: dental health survey(s); dental public health; enamel; epidemiology; fluoride(s); risk factor(s).