The steps of dental root canal treatment can be generally divided into three steps. First, root canal preparation. Firstly, the length of the root canal should be determined, and in clinical practice, root canals are usually prepared using a root measuring instrument. Second, root canal disinfection. Calcium hydroxide should be commonly used and placed in the middle 1/3 of the root canal. Third, root canal filling. There are two general methods: 1) hot glue method, 2) paste filling, with the use of glue tips. The lateral pressure is used to make the glue tip tightly filled, and then the anatomical structure of the tooth shape is restored with light-cured resin.