You and I both know that dental fluorosis affects the low-income and non-white populations at twice the rate as the white population, so when a privileged person sees a lot of stained teeth in poor communities or among the First Nations or Black populations, they dismiss it on poor hygiene or other excuses, but they are wrong. It's the result of poisoning during early childhood by fluoride in tap water. Plus this is the leading indicator, adolescents. Additionally, those who can afford it will get veneers or crowns to disguise the damage on those teeth that show when they smile. 
 
1962 memo: http://fluoridealert.org/wp-content/uploads/1962_01_10_Blacks_Fluorosis.pdf
2011 email: http://fluoridealert.org/wp-content/uploads/2011_04_27_foia_fluorosis.pdf
2010 CDC report: http://www.cdc.gov/nchs/data/databriefs/db53.pdf
Table 23: https://www.cdc.gov/mmwr/preview/mmwrhtml/ss5403a1.htm#tab23