However, the habit of taking certain foods or drinks can make teeth more brownish.

Even though teeth can be bleached again with procedures performed by dentists, there are actually a number of easy and inexpensive ways to restore the natural white luster of teeth.
Use baking soda as toothpaste and bleach
Additional ingredients to make this cake have long been used as a substitute for toothpaste in cleaning teeth. But baking soda can also serve as teeth whitener. The chemical compounds in baking soda are mildly abrasive so they can remove thin surfaces on the teeth. But because of the abrasive nature, baking soda should be used only once or twice a month.
Chew gum
Chewing sugar-free gum will help reduce levels of acid and bacteria in the mouth. Chewing action will stimulate the mouth to produce more saliva containing enzymes to protect teeth from stains.