In 1947, a series of human experiments were begun on patients in Vipeholm Mental Hospital in Sweden. Unknown to the Swedish government, but sanctioned by the dental community and the confectionery industry, a group of mental patients were fed copious amounts of sweet foods, like chocolates and caramels, in a full-scale experiment designed to bring about tooth decay. The experiments provided extensive knowledge about dental health, and resulted in the breakthrough findings that the intake of sugar was linked to dental caries, that certain physical qualities of sugars (such as their stickiness) influence caries risk, and that the frequency with which sugary foods are consumed also affects caries development.1

While, scientifically speaking, the experiment was a success, with more having been learned about dental health and caries than from any previous study, the study would never have taken place today: It violates the principles of medical ethics. Many subjects ended up with their teeth completely ruined to provide fodder for subsequent studies that continued to increase dental knowledge, and to provide much of the information that follows about the oral environment factors that play a role in the dental caries process.