When yellow teeth cannot be cleaned, you can take measures such as pressure removal under sandblasting, cracked drill to grind away discolored dental tissues, application of smooth lathing to grind away, and dental preparation, as follows: 1. Pressure removal under sandblasting: When hidden cracks exist on the labial and lingual surfaces or deeper sulcus point gaps are formed on the jaw surface, they can be removed by pressure under sandblasting, and the rough tooth surface can be polished when it is easy to absorb exogenous pigments. 2. Cracked drill to grind away discolored dental Tissue: When enamel hypoplasia or poor mineralization occurs, substantial defects appear on the tooth surface, and yellow soft scale is easily deposited, the discolored tooth tissue can be removed by applying a cracked drill and filled with composite resin. 3.Application of smooth car needle grinding: When suffering from fluorosis or tetracycline teeth, and the surface layer of enamel shows yellow-brown patches, smooth car needle grinding can be applied and then coated with fluoride-containing drugs to enhance the hardness of the enamel. 4.Dental preparation: When the tooth is discolored after root canal treatment, tooth preparation can be carried out to make all-porcelain veneer or full crown restoration.