Patients often say that they have lost a piece of their teeth, but in fact it is often the case that the calculus on the teeth has fallen off. Calculus is a kind of mineralized or mineralizing plaque and soft scale deposited on the surface of the tooth surface or restoration, which is formed by the gradual deposition of inorganic salts such as calcium salts from saliva or gingival sulcus, and is not easy to remove after formation. The glycoproteins in saliva can form a 1-15 micron thick film (called the acquired film) on the tooth surface, making bacterial attachment possible. Once the acquired film is formed on the tooth surface, bacteria will attach to it within only a few minutes, depositing in layers. This bacterial deposit, called plaque, provides the essential mineralized core for tartar formation, while the inorganic salt component required for tartar formation is derived from saliva. Saliva is supersaturated with mineral salts such as calcium and phosphorus, and when saliva flows out of the duct mouth and into the oral cavity, the carbon dioxide tension contained is reduced by half. Carbon dioxide escapes saliva PH value increases, calcium and phosphorus ions that is precipitated from the supersaturated state, deposited in the core of the surrounding. At the same time as the mineral salts are deposited, the bacteria residing in the core are gradually mineralized, and over time, mineralized tartar is formed.