Add milk
Estafan says that a splash of milk can make a real difference for your teeth. A study published in the International Journal of Dental Hygiene found that casein, the main protein in milk, can latch onto tannins in tea (bitter-tasting particles that leave residue on teeth) and prevent staining. Coffee also has small amounts of tannins, so coffee drinkers can reap these dairy benefits too. For the best results, use animal milk; soy milk won’t do the job.
Sip water between cups of coffee
A swig of water can wash away staining liquids quickly before they start to set into your teeth. Plus, drinking enough water is a great way to help you stay hydrated throughout the day.
Drink it quickly
Let’s say you and your coworker both grab cups of coffee when you get into the office. You drink your whole cup in five minutes, but your coworker takes his time and finishes the same amount of coffee in two hours. Lucky for you, Estafan says that your teeth will be the less-stained ones. Since your coworker exposed his teeth to the coffee for a longer period of time, his will be more stained.