The connection between fluoride and dental health began to be seriously explored in the early twentieth century. By the 1950, communities across North America had begun fluoridating their water supplies. Ontario was one of the first places in the world to introduce community water fluoridation as a public health initiative to reduce tooth decay.
The first Canadian community water fluoridation trials began in Brantford, Ontario in 1945. At last count, 9,229,015 people in Ontario, or 75.9 percent of the provincial population, have access to fluoridated water.i Currently, CWF is practised in more than 30 countries around the world, providing more than 370 million people with optimally fluoridated water.
Information as per the ODA