Now the demand for calcium hydroxide in the market is increasing, as a cheap chemical it has a wide range of applications in various industries. Calcium hydroxide is a white powdery solid, also known as slaked lime. Calcium hydroxide has the commonness of base and is a strong base. Calcium hydroxide its product uses are: 1, construction: trinity soil, lime paste. Brush the wall (Ca(OH)2+CO2=CaCO3↓+H2O)2, agriculture: preparation of Bordeaux liquid as a pesticide (Ca(OH)2+CuSO4=CaSO4+Cu(OH)2↓ Calcium sulfate slightly soluble in water) 3, industry: Preparation of sodium hydroxide (also known as caustic soda, caustic soda, caustic soda) (Ca(OH)2+Na2CO3=CaCO3↓+2NaOH), preparation of low-cost bleaching powder (2Cl2+2Ca(OH)2=CaCl2+Ca(ClO)2+2H2O) 4. Packaging, storage and transportation: Packed with plastic woven bags lined with polyethylene plastic film bags, each bag net weight 25kg. It should be stored in a dry warehouse to prevent moisture. 5. Clinical application: First, live pulp amputation, the purpose of live pulp amputation is to remove diseased crown pulp, preserve the vitality of healthy root pulp and pulp, maintain the normal absorption and fragmentation of deciduous teeth roots, and promote the further development of young permanent teeth roots and the blockade of apical foramina. Second, apicoplasty, when the roots of young permanent teeth are still in the development stage, due to some reasons, such as dental caries, deformity, trauma, so that the pulp necrosis, root development is suspended, resulting in an open state of the root tip. The treatment of such affected teeth has been very difficult for stomatologists, because of the large root canal cavity, it is very difficult to achieve complete debridement with conventional root canal expansion, and it is simply impossible to make the root canal tightly filled. The third, pulp cap, is the treatment of directly masking the exposed pulp with drugs to promote pulp healing and repair, usually applied to the health of the novel exposed pulp. At present, the clinical effect of calcium hydroxide preparation has been recognized. Although calcium hydroxide has many uses, it is corrosive, and there are security risks in the process of production and use. When working, we must pay attention to protect the respiratory organs, wear work clothes made of dust-proof fiber, gloves, sealed dust-proof glasses, and apply grease ointment to prevent dust inhalation.