A deep cavity in a single Neanderthal molar from Siberia looks less like random damage and more like a deliberate act of treatment, a finding that pushes invasive dental care far deeper into human history. The tooth, known as Chagyrskaya 64, came from Chagyrskaya Cave in Russia’s Altai region and dates to about 59,000 years ago. In a study published in PLOS One, Alisa Zubova of the Peter the Great Museum of Anthropology and Ethnography in St. Petersburg and colleagues argue that the tooth was not simply worn down by age, broken by chance, or altered after burial. Instead, they say, a Neanderthal appears to have drilled into a decayed molar to reach infected tissue and ease pain. That makes the specimen the oldest known evidence of successful dental treatment, and the first such case documented outside Homo sapiens. “We were intrigued by the unusual shape of the concavity on the tooth’s chewing surface,” Zubova said. “It differed from the normal morphology of the pulp chamber and did not match the typical pattern of carious …