DEAR DOCTOR, I took up smoking a few years ago but this has caused damage to my teeth and affected my breath too. My teeth are not as white and clean as they used to be, and I am planning to go for teeth whitening. How safe is this and are there any side effects I should look out for? ISAAC DEAR ISAAC, You have finally realised that smoking has damaged your teeth. Cigarette smoke contains tar which contains carbon along with many other chemicals. Nicotine is the active ingredient. This carbon causes blackening of finger nails, lips, and teeth. It also imparts a foul smell to breath. Teeth contain pores just like the skin. Nicotine and tartar from cigarette smoke are just absorbed by these pores, resulting in deposits of tartar around which bacteria cause plaques. This causes brownish, blackish or yellowish discoloration. The severity of discoloration depends on duration and quantity of cigarettes smoked and personal hygiene. Smoking also leads to recurrent teeth and gum infections due to deposit of tartar plaques, in and around gums. This tends to weaken the teeth and may cause loss of one or more teeth. As such, regular use of mouth wash and dental flossing can help retain the original colour of teeth to some extent, in spite of smoking. Hydrogen per oxide based antiseptic mouth washes are good in this regard, as they help to cleanse the teeth to some extent and remove stains and discoloration over surface of teeth. Use of food substances such as apple, carrots helps to clean the teeth naturally, by removing deposits of food particles and also tartar. However in case of extensive discoloration of teeth, whitening remains the best option. Brushing teeth with baking soda and hydrogen per oxide can be done easily at home. Baking soda is good for teeth whitening, because it helps remove stains from the surface of teeth. Rubbing banana, orange or lemon peels over the teeth also helps to remove stains. Professional whitening done in a dentist’s office takes about an hour-where hydrogen per oxide based gel is used for teeth whitening. It can be repeated once every 3 to 6 months. Teeth whitening impart a clean, white look to the teeth. This enhances one’s beauty and boosts his self-confidence as well. If good dental hygiene is maintained after this, and smoking avoided, the, “white” look can be maintained. Dental whitening procedures can cause abrasion over the gums, increasing gums sensitivity after the procedure. Enamel can be damaged by repeated whitening, thus causing risk of discoloration in future. They can also weaken the roots, increasing risk of tooth loss. After teeth whitening, if one continues to smoke or use excess tea or coffee, stains and discoloration can relapse. Dr Rachna Pande is a specialist in internal medicine E-mail rachna212002@yahoo.co.uk