Original sentence: Many municipalities fluoridate their water supplies in the belief that this practice will reduce tooth decay at a low cost.Those opposed to public fluoridation of drinking water contend that water fluoridation can have harmful health effects such as dental fluorosis and bone cancer
Edited sentence: Many municipalities fluoridate their water supplies, which reduces tooth decay at a low cost.Those opposed to public fluoridation of drinking water contend that water fluoridation can have harmful health effects such as dental fluorosis and bone cancer, though medical research shows this is not the case