There are many reasons why your child’s teeth may not be white. Poor oral hygiene habits and plaque buildup can cause teeth to appear discolored. Certain medications can change the color of teeth, as can foods and drinks that stain, like cola and grape juice. If your child’s secondary teeth have erupted, they may appear yellow compared to their whiter primary teeth. Don’t be alarmed; it’s normal for adult teeth to look yellow because they contain more dentin. As your child gets older, their teeth will whiten.