Beeswax as dental filling on a neolithic human tooth

Abstract

Evidence of prehistoric dentistry has been limited to a few cases, the most ancient dating back to the Neolithic. Here we report a 6500-year-old human mandible from Slovenia whose left canine crown bears the traces of a filling with beeswax. The use of different analytical techniques, including synchrotron radiation computed micro-tomography (micro-CT), Accelerator Mass Spectrometry (AMS) radiocarbon dating, Infrared (IR) Spectroscopy and Scanning Electron Microscopy (SEM), has shown that the exposed area of dentine resulting from occlusal wear and the upper part of a vertical crack affecting enamel and dentin tissues were filled with beeswax shortly before or after the individual's death. If the filling was done when the person was still alive, the intervention was likely aimed to relieve tooth sensitivity derived from either exposed dentine and/or the pain resulting from chewing on a cracked tooth: this would provide the earliest known direct evidence of therapeutic-palliative dental filling.

Figure 1. The Lonche jaw from a karstic cave of southern Slovenia.

Scale bar, 10 mm.

Figure 2. The Lonche canine.

A) Distal-mesial virtual section of the entire Lonche 1 lower left canine (resolution 18 µm). B) 1. Micro-CT detail of the crown showing the thickness of the beeswax (in yellow). Beeswax exactly fills the shallow cavity in the exposed dentin and the upper part of the crack (resolution 9 µm). 2. Three-dimensional virtual reconstruction and 3. microphotograph of the tooth crown in occlusal view with indication of the surface covered by beeswax (within the yellow dotted line). C) Micro-CT based cross-sections of the tooth showing the enamel cracks along the labial and lingual aspects (resolution 9 µm). The positions of the cross-sections are shown in Figure B2. The beeswax is colored in yellow. Scale bars, 2 mm.

Figure 3. Volume rendering of the canine crown showing the fractures through the dental tissues in transparency.

The main vertical fracture (in blue) and the sub-horizontal ones (in red) are shown in lingual (A), distal (B) and occlusal view (C). Scale bar, 1 mm.

Figure 4. Comparison between the IR spectrum of Lonche filling material and a modern sample of natural beeswax.

The Lonche spectrum is an average of 10 analyses.

Figure 5. Calibration of radiocarbon dates of the Lonche jaw and beeswax.

A) Calibration of a single radiocarbon date (DSH1761 = jaw) using the IntCal09 data set and OxCal program v.4.1.3 . B) Calibration of a single radiocarbon date (OZM924 = beeswax) using the IntCal09 data set and OxCal program v.4.1.3 . Blue lines depict the IntCal09 calibration curve (shown at 1σ range). Red curve indicates the Gaussian distribution of the radiocarbon date. Grey histogram represents the probability distribution of the calibrated age. Black lines depict calibrated age ranges for 1σ and 2σ. Open circle and cross represent weighted mean and median, respectively.

Figure 6. SEM images of the occlusal surface of the Lonche canine after the beeswax was removed.

The Figures A and B, respectively taken before and after cleaning the occlusal surfaces from beeswax superficial residues, show the exposed area of dentine resulting from occlusal wear and the vertical crack still filled with beeswax. Some chippings with round and smooth edges, indicated by the white arrows in Figure A, are present on the occlusal buccal margin of tooth. In Figure A1 residues of beeswax cover the edges of the vertical crack, while Figure B2 shows that some enamel fragments are lost in the same area, indicated by yellow arrows. Scale bars, 200 µm.