Dear Lybrate user, blackening of teeth can be due to deposition of external stains or plaque deposits on the teeth. Visit your local dentist
to get a scaling/professional cleaning done. This treatment does not change the natural color of teeth but removes all the deposits thoroughly which are otherwise hard to clean with a toothbrush. Your dentist will also advise you to use a mouthwash for 2 weeks after scaling. All types of coffee or tobacco stains can be removed by scaling. If there is any decay that is causing change in color or cavity, the dentist can advise treatment for that after a clinical checkup.