Trends in Caries Experience in Children in Nevada and the Effect of Water Fluoridation (2001 – 2010)

Purpose: In 1992 in Nevada 2.1% of the population was served by fluoridated community water systems. In 2000, legislation required water fluoridation for populations of 100,000 between 0.7mg/L and 1.2mg/L in community systems. In January 2011, the DHHS recommended lowering standards for community water fluoridation systems because of a government study showing that about 2 out of 5 adolescents presented with tooth streaking/ spottiness due to fluoride exposure. This new proposal recommended new fluoridation levels fixed at 0.7mg/L. This study analyzed trends of caries experience in Nevada children and the effect of water fluoridation over time. Methods: Trained/calibrated licensed dental examiners performed oral health screenings on >77,000 middle/high school students(49% males;51% females) in mobile dental clinics across 9 academic years(2001-2010) throughout Nevada. Untreated caries(d-score), caries experience(df-score), and decayed, missing and filled teeth(DMFT) indices were collected. Mean scores were computed by county across all years. Counties were divided into Clark(fluoridated), Washoe(legislation controversy over fluoridation), and all others(not fluoridated). Results: DMFT scores in Clark decreased significantly since 2001 with a slight increase in 2007(p<0.05). Washoe was significantly higher than all other counties across all years(p<0.05). Trends were similar in caries experience and untreated tooth decay with Washoe having higher mean scores then Clark County and Clark seeing decreasing trends. Conclusion: Fluoridation maybe perceived to present unreasonable health risks, particularly among children, but trends in Nevada show that fluoridation can be an effective way to prevent tooth decay especially in areas with low natural concentration of fluoride in the drinking water.