To understand how to make our teeth whiter, we must first take into account what turns them into yellowish ugly choppers. A teeth is porous and therefore is not immune to stain or discoloration. The food that we eat, the drinks that we drink, the medication, the habits, even traumas or falls can cause discoloration. Coffee and tea, two of the popular sources of caffeine for most people, is a major contaminant of white teeth. Nicotine and tar along with the other chemicals in a smoke can tarnish the white gleam as well. A fall directly to the teeth can cause tooth death or tooth necrosis which causes discoloration.