The Mayans are credited with being the masters of cosmetic dentistry as they were known to decorate teeth by embedding them with precious stones or by carving notches and grooves into them. Tiny holes were chipped out of teeth and ornamental stones—including jade—were attached with an adhesive made out of natural resins, such as plant sap, which was mixed with other chemicals and crushed bones. The dentists likely had a sophisticated knowledge of tooth anatomy because they knew how to drill into teeth without hitting the pulp inside.