Dental hygiene is big business; sales of teeth whitening products are soaring. After your braces, will your teeth be stained or Hollywood white? There are two ways that teeth may become discolored. The antibiotic tetracycline, excess fluoride, or trauma can darken or reveal the yellow inner tooth. Coffee, tea, cola drinks, or smoking attack the outer surface. Common whitening methods target only outer stains.
The yellow layer beneath the white enamel protects your teeth as you chew. Enamel, the hardest substance in your body, is composed primarily of calcium and phosphate ions bundled into microscopic crystalline rods (see photo). When spaces between the rods fill with organic material, the stains become too deep to brush away.