Silver amalgam is an alloy composed of silver, copper, tin, zinc combined with mercury elements, a silver-colored material, widely used to fill dental cavities. According to statistics, silver amalgam accounts for 80% of all dental restorations in posterior teeth, and has a clinical life of up to 10-30 years. Because of the mercury content of amalgam, there has been concern about the potential health hazards of inhaling and absorbing mercury vapor from amalgam. Many governments and agencies have also tested the safety of silver amalgam and concluded that the body can absorb mercury vapor released from silver amalgam. An expert panel consisting of the U.S. Department of Health, the European Union Executive Committee, and WHO concluded that there is no reliable evidence of a causal relationship between silver amalgam and adverse health effects, except for the rare possibility of a metabolic reaction. However, the accelerated corrosion of silver-mercury during chewing and brushing releases small amounts of mercury vapor and mercury ions, which are swallowed in saliva and enter the gastrointestinal tract in very small amounts, but mercury vapor is most toxic after methylation and alkylation, and 75% of inhaled mercury vapor is absorbed by the lungs. However, even for the most sensitive social groups, it is safe to absorb about 20 μg of mercury vapor per day, because this amount is two to 200 times the amount of mercury absorbed per day due to silver-mercury dissolution. With the development of science and technology and the improvement of people’s living standards, the gradual elimination of silver amalgam from dental filling materials has been a historical necessity, not because “mercury is one of the most dangerous environmental toxins”, but now there are composite resin materials and porcelain materials with high strength, high wear resistance, realistic color, and high adhesion to the teeth available. And there is no need to use the color and teeth do not harmonize, fragile, with micro-leakage between the teeth, there is a “toxic” controversy of silver amalgam.