Dental drilling began earlier than previously thought, according to a recent report in Nature (Coppa A, Bondioli L, Cucina A et al., Nature 2006; 440: 755-756). An international team of researchers have discovered eleven drilled molars in a Neolithic graveyard in Pakistan dating from 7,500-9,000 years ago, at least 1,500 years earlier than previous evidence of drilled teeth.
The teeth were found at Mehrgarh in Baluchistan province and were drilled using flint drill heads that have been found at the site. Varying in depth from 0.5 to 3.5 mm, the holes were drilled into the enamel or secondary dentine on the occlusal surfaces of the teeth, except for one that was located on the distal-buccal cervix of a lower first molar. The team found evidence of surprisingly complex procedures, with the teeth of at least one individual showing signs of subsequent carving of the cavity wall. Marginal smoothing of the drilled areas confirms that the drilling was performed on live people who continued to chew on the tooth surfaces after they had been drilled.
The eleven crowns were exclusively either first or second permanent molars, a fact that the team says rules out drilling for aesthetic purposes, as the teeth were too far back in the mouth. Although the exact motive for the drilling remains unclear, four teeth show signs of caries associated with the hole, which could indicate that the drilling was for therapeutic or palliative reasons in some cases. The flint drill heads at Mehrgarh were found associated with beads, suggesting that skills developed for bead making were successfully transferred to drilling teeth.
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Stone age 'proto-dentistry' revealed. Br Dent J 200, 425 (2006). https://doi.org/10.1038/sj.bdj.4813555
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