Cause of discoloration ? smoking, coffee, tea, drugs, aging, staining food (wine, blueberry, etc.) genetics. You may have a yellow bacterial film called ?plaque? that occurs naturally in mouth that can build up. If not removed it hardens to form tartar. Advise deep cleaning, polishing, whitening (bleaching) procedures, artificial enamel filling or capping. Advance procedures can be done with laser. Use sensoform gum paint & snowdent tooth paste for whitening until then. Apply snowdent paste on the teeth. Wait for 10 to 15 min. Then brush your teeth with the same paste. Applying it overnight for better results.