The Maya believed that their breath was connected to the divine. Many people cleaned their teeth to purify it. A new analysis shows that the sealant used to hold these jewels in place may have had therapeutic properties.

During the Classic period (200 to 900 C.E.), many lowland Maya people in what is now Guatemala, Belize, and Mexico affixed colored stones to the front of their teeth. Maya dentists drilled holes into the teeth and fit them with stones and applied a sealant as part of a rite of passage to adulthood.

More than half of the modified teeth from archaeological digs still have their stone inlays intact. Hydroxyapatite, a mineral obtained from ground teeth and bones, was found in previous analyses. The materials helped strengthen the mixture, but wouldn't have been sticky enough to hold the stones in place. The binding agent's nature has been a mystery.

The Center for Research and Advanced Studies of the National Polytechnic Institute in Mexico had a researcher analyze the sealants in eight teeth found in the Maya empire. One technique distinguishes groups of organic compounds based on the amount of light they absorb, while the other separates chemical mixtures using heat.

The researchers reported last month in the Journal of Archaeological Science: Reports that they found 150 organic molecules in the sealants. The binding component of each sample was used for their water-repelling and gluelike properties. Statistical analysis showed that the sealant could be divided into four groups based on the location. The ingredients seem to have been thought out.

Some research suggests that pine trees can help fight tooth decay. Sclareolide, a compound found in Salvia plants that has antibacterial and antifungal properties, is currently used as an aroma fixative in the perfume industry. The essential oils from mint plants were included in the Sealants from the remote outer Copán region. The authors say that this ingredient was not found elsewhere.

The binding properties were the most important for the Yucatec, a group that is part of the historic Maya civilization. She says that ancient people may have been aware of the effects of these plants.

The study finally addresses the question of how these stones were affixed, says an anthropologist from the University of California, Santa Cruz. She says that the Maya dentists were good at their work, but they also knew how to avoid potential unwanted side effects.

The antiseptic and therapeutic properties are something that the dental anthropologist at John Moores University would like to see more evidence about.

Vera Tiesler says that oral hygiene was important to the Maya. The Maya king of Palenque, who died at the age of 80 with virtually all of his teeth missing, was a tribute to the remarkable dental skills of his time.