In 1928, the substance of natural fluorine in water was discovered can prevent tooth decay. In the early 40 's, the analysts estimated annually to 700 million case of tooth decay in the United States. It made for oral diseases became one of the most common health problems for Americans. Procter & Gamble, the company immediately embarked on the production of toothpaste is based on research on the application of fluorine and put the name of the product is Crest.
đang được dịch, vui lòng đợi..
