April 7 (UPI) -- Researchers have discovered ancient dental fillings in northern Italy, the world's oldest. The fillings were found inside a pair of 13,000-year-old front teeth. They were made of bitumen, a semi-solid form of petroleum.
Each of the two teeth feature large cavities. Marking on the walls of the holes suggest the cavities were hollowed out and enlarged by stone tools. While analyzing the holes, scientists found residues of bitumen. Researchers also found plant fibers and hair trapped in the asphalt.
The fillings likely served the same purpose they do today, to reduce pain and keep food out of the cavities. Archaeologists estimate the asphalt and plant matter filler was chosen for its antiseptic qualities -- used to prevent infection.
"It is quite unusual, not something you see in normal teeth," Stephano Benazzi, an archaeologist at the University of Bologna, told New Scientist.
Researchers described the discovery in the American Journal of Physical Anthropology.
Archaeologists have previously discovered the use of beeswax as filling inside a 6500-year-old tooth recovered in Slovenia.