Children may like the taste of toothpaste and be tempted to swallow it. When they use too much toothpaste, they could potentially swallow enough fluoride to develop fluorosis, which only has an effect on developing teeth. While fluorosis is not a disease, it can alter the appearance of teeth. In its mildest form, it can leave white flecks or streaks on developing teeth. Severe cases can lead to brown spots on teeth. If you notice flecks or streaks on your children’s teeth, see your dentist for possible treatments that may include teeth whitening or other cosmetic treatments for moderate to severe cases.