Dentistry has improved greatly in the past few years. By the end of the 19th century, it was determined that cavities are caused by cariogenic bacteria. Briefly, the mechanism of cavity production is as follows: cariogenic bacteria create glucan and glucan create plaque. Next, they feed on sugar to generate acids such as lactic acid in the plaque. Experiments of Dr. Hattori show that green tea catechin can suppress the process of glucosyl transferase by cariogenic bacteria to produce glucan. Other experiments by Dr. Sakanaka have verified that green tea catechin can destroy cariogenic bacteria. It has been known for some time that small amounts of fluorine can strengthen teeth and help prevent cavities. For this reason, many cities add fluorine to their drinking water. Green tea contains natural fluorine and is thought to aid in the reduction of cavities in school children. Dr. M Hattori et al., Chem. Bull., (1990). Dr. S. Sakanaka et al., Agrec. Biol. Chem., (1989).