https://www.mouthhealthy.org/en/az-topics/e/dietary-acids-and-your-teeth
https://www.mouthhealthy.org/en/az-topics/f/fluoride
http://www.cnn.com/2016/06/08/health/adults-flossing-teeth/index.html
http://www.webmd.com/brandcast/default.htm?prx_t=tzUCAuGsHAItkLA