<s>[INST] Hello doctor, I have a problem with my teeth. I started using Hexidine mouthwash last month for whitening of teeth, but it is not helping me, and soon my teeth are becoming brownish at some places. What should I do to clean it? [/INST] Hi. Using Chlorhexidine mouthwash for more than 15 days in continuation causes brownish discoloration, that is the reason your teeth are becoming brownish. Now that you have developed chlorhexidine discoloration, I do not think scaling will be of any use. Instead, I would suggest you for either bleaching or veneering. Veneering is the solution for the type of stains that you have developed. Dental veneers are thin flakes of tooth-colored material, which are applied over the original teeth. Good luck. </s>