The difference between stannous fluoride and sodium fluoride is that only the first kills bacteria while both have been shown to rebuild enamel. Stannous fluoride also has the disadvantage of staining the teeth when it is included in a compound that contains tin.
Stannous fluoride was an ingredient added to toothpaste in the 1950s until the better-tasting and cheaper alternative, sodium fluoride, was developed. Stannous fluoride is helpful for people whose salivary glands do not produce enough saliva. Saliva is important because it helps protect against acid and tooth decay. Stannous fluoride is meant to be applied after brushing, once daily or as directed by the dentist and left on for 30 minutes before the patient resumes eating or drinking. It should not be used like ordinary toothpaste. Patients should tell their dentist or pharmacist about any allergies they have before using this product and mention any history of mouth sores.
Sodium fluoride, which is present in many commercial toothpastes, can also be used as an oral supplement. In this case, the consumer should beware of exceeding the recommended daily dosage from various sources combined. Since fluoride is added to many communities' drinking water, the government has issued guidelines on fluoride intake for infants, children, adolescents and adults.