6. Conclusions

This study has presented an inventory of post-mortem alterations in archaeological teeth observable at histological scale. Various types of diagenetic alterations are observed. Our previous study showed that the variation in diagenesis may result from tissue types, differences in taphonomic processes and specific burial conditions. Here, a photo catalogue has been made that can aid other workers within the fields of archaeology, palaeontology and forensics. In general, the study illustrates how dental tissue suffers from the same diagenetic issues as bone and sometimes to a severe degree. In addition, dental elements may be made more vulnerable to post-mortem diagenesis as a result of pathologies. Consequently, dental tissues should also be screened before any further chemical and molecular analysis. As suggested for bone, the pattern of microbial attack may indicate the pathway of bacterial/fungal attack, also suggesting timing, before or after skeletonisation of the remains. However, a fairly limited set of samples was used and larger, more systematic characterisation of the type of histological alterations occurring in teeth is needed. To improve understanding of the observed features, chemical and mineralogical analysis of infiltrations and inclusions would be of great value, as well as high-resolution 3-D imaging of microbial tunnelling and microbial DNA analysis.

The differences and similarities found between bone and dental diagenesis can be summarised as follows:

• Similar tunnel morphologies and type of inclusions (organic and inorganic) are observed.
• As with bone, microbes may attack from external or internal surfaces.
• Severe bioerosion can be found in teeth but this seems to leave comparatively larger areas unaffected than in bone.
• No completely bioeroded tooth was observed whereas complete bioerosion is relatively common in bone.
• As in bone, tunnelling microbes/bacteria respect the microarchitecture of dentine and cementum. However, tunnels were observed that crossed the more crystalline layer of Tomes. Additionally, possible enamel tunnelling was observed.
• Generalised destruction, staining and inclusions (both organic and inorganic) may affect bone and teeth to a similar degree.
• Several not previously described morphological features, presumably relating to microbial activity have been observed in the current assemblage of teeth, including possible enamel tunnelling. Further investigations are necessary to confirm their nature.
• Dentine and cementum are rarely affected by microfissuring whereas this is a common occurrence in bone and enamel.