Cause of discoloration ? Smoking, coffee, tea, drugs, aging, staining food (wine, blueberry, etc) genetics. We need more investigations with clinical examination to decide upon treatment. You may need deep cleaning along with whitening (bleaching) procedures and / or artificial enamel filling and / or capping. Advance procedures can be done with laser. Use 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. DENTAL TIPS: - Visit a dentist every six months for cleaning and a thorough dental check-up. Limit sugary food to avoid tooth decay. Gargle your mouth thoroughly after every meal. Scrub gently to clean your tongue with a tongue cleaner. Floss all your teeth inter dentally & brush twice daily, morning & night, up & down short vertical strokes, with ultra-soft bristles, indicator brush. Tooth brush to be changed every 2 months.