Chewing gum in various forms has been around since ancient times. The Greeks chewed sap from the mastic tree, called mastiche. On the other side of the world, the ancient Mayans favored the sap of the sapodilla tree (called tsiclte). Native Americans from New England chewed spruce sap—a habit they passed on to European settlers. Today, the base used for most gum products is a blend of synthetic materials (elastomers, resins and waxes in various proportions). However, chewing gum is as popular as ever. Consumers may be used to thinking about chewing gum as a kind of candy, but this category of the ADA Seal recognizes chewing gum that has demonstrated scientifically that it can protect the teeth.