Dental calculus is deposited on the surface of the tooth or restoration surface calcified plaque and sediments, dental calculus formation is generally due to the accumulation of plaque and mineral deposition, as follows. 1. Accumulation of plaque: plaque is the organic matrix for mineralization of dental calculus deposition, is the core of mineralization, crystals are deposited in the plaque, and mineralized material is deposited on the surface of the plaque. 2. Deposition of mineralized material: Calcium, phosphorus and other mineralized material in saliva and mineral salts in gingival sulcus exudate are the main sources of inorganic salts in dental calculus. Mineralization begins as small foci, then gradually increases in size and converges to form large tartar, and tartar provides an ideal rough surface for further accumulation and mineralization of plaque.