Two molar teeth of around 63,400 years old show that Neanderthal predecessors of humans may have been dental hygiene fans, the Web site of newspaper El Pais reported on Tuesday.
The teeth have "grooves formed by the passage of a pointed object, which confirms the use of a small stick for cleaning the mouth," Paleontology Professor Juan Luis Asuarga told reporters, presenting an archaeological find in Madrid.
The fossils, unearthed in Pinilla del Valle, are the first human examples found in the Madrid region in 25 years, the regional government's culture department said.
Neanderthals were predecessors of modern humans who inhabited much of Europe, North Africa and parts of Asia from about 125,000 to 30,000 years ago.
"There are two (teeth), perfectly preserved, in which the wear and tear of a human of about 30 years old is perceptible," a government statement said.
Experts also found diverse animal fossils, including remains of hyenas, bears, deer and rhinoceroses.