Before restoring a defective tooth, the basic treatment must be done well, for example, the decayed dentin needs to be removed, if there is pulpal and periodontal inflammation, the inflammation should be eliminated first, and orthodontic correction should be performed if the tooth is significantly shifted. Some teeth with poor retention of remaining dental tissues need to undergo necessary orthodontic traction or crown lengthening to expose enough dental tissues, such as all the foundations are laid before a building can be built on them. At this point, depending on the amount of defect, a variety of restorative options are available, such as veneers, inlays, full crowns, pile core crowns, fixed bridges, and dental implants. The doctor chooses different materials according to the patient’s own situation, as well as the patient’s economic conditions and the expected requirements for the restoration, and together they decide whether to make metal crowns, metal porcelain crowns, or make all-ceramic crowns, etc.