After caries and root canal treatment, filling restorations and crown restorations are routinely performed. These two methods are applicable to all decay and defects, but different restorations are used depending on the location and size of the defect. Filling is done with various materials, while crown restoration is done with a full crown after preparation of all sides of the tooth. Nowadays, CAD/CAM restoration is adopted for decay and certain degree of defect, which takes the image in the mouth, designs and grinds it in vitro, grinds out the same porcelain block as the defective area on a block, and then bonds it into the defective area after adjustment. Compared to full crowns, the amount of tissue removal is greatly reduced, and the number of visits also becomes a chairside visit. Because it is an integral porcelain block, it is more durable than other filling materials such as resin (which is filled in layers) and has higher strength and wear resistance than resin.