Have you noticed that many toothpastes now have expiration dates? This is because all toothpastes containing fluoride are regulated by the Food and Drug Administration, which now requires expiration dates. Up to that date, normally two years after manufacture, all the fluoride must be available to bind to tooth enamel, hardening it against the acid that causes cavities. Once that date is past, some of the fluoride ions may have bound with the caking agents into a salt or a crystal and thus aren’t available to bind to tooth enamel. Also, depending on the length of time and temperature of storage, the paste could separate so that an uneven amount of fluoride or flavoring agent is expressed at each squeeze. The viscosity might change and the toothpaste might not have the same consistency.
So, check the date! In our Long Island dental office we regularly check the expiration dates of all of our dental products.