There are many reasons for tooth discoloration, including exogenous factors, such as pigmentation, plaque, etc., as well as endogenous factors, such as tetracycline, etc. Different reasons for tooth discoloration can be used in different ways to make them white again, and common methods include teeth cleaning, cold light teeth whitening, dental veneers, and so on. 1. Teeth cleaning: If teeth discoloration is caused by exogenous factors such as plaque, calculus, pigmentation, etc., teeth can be whitened by removing stains through teeth cleaning. However, teeth cleaning can only remove the dirt attached to the surface of the teeth, so that the teeth to restore the original color, such as teeth originally yellowish, you can consider the use of other teeth whitening methods at the same time. 2. Cold light whitening: If the discoloration of teeth is caused by tetracycline, fluorosis or other problems with the teeth, you can consider using cold light whitening to whiten your teeth. 3. Dental veneers: If the discoloration of the teeth is more serious, cold light whitening and other ways can not achieve better results, you can also consider the way of dental veneers, quickly make the teeth whiter, common dental veneer materials include porcelain veneers and resin veneers. If you want to whiten your teeth, you should go to a regular hospital for an examination to determine the cause of the problem, and then choose the appropriate way to whiten your teeth under the guidance of your physician.