"Fluoride is one of the most toxic inorganic chemicals in the Earth's crust, but it is believed that at a concentration of 1ppm, or 1m g/mL in public water supplies, and at the concentrations used in dental preparations, it is both safe and beneficial to teeth. However, with increasing experience, doubts about both safety and efficacy have arisen. While there is evidence of harm to the stomach, kidneys, thyroid, bones and teeth at higher concentrations, evidence for harm at concentrations around
I. Targets and methods Based on diagnosis standards formulated at the 1981 Shijiazhuang National Prevention of Endemic Fluorosis Meeting, 30 patients were chosen, 15 men and 15 women with an average age of 45, average height of 1.63 meters, and average weight of 54 kilograms, and all with clinical diagnoses of early sclerosis. Upon a clinical comprehensive physical examination and biochemical examination, no cardiovascular diseases were found. Conditions for taking the frontal heart X-rays: fast
