Investigating beta-thalassaemia in micro-CT scans of deciduous teeth

To assess if 'iris-like' changes to deciduous incisors are a consistent feature associated with archaeological cases of beta-thalassaemia.

Deciduous teeth from three individuals from the Romano-British cemetery of Poundbury Camp, Dorchester, England, and one individual from the contemporary site of Butt Road, Colchester, England, identified as having transfusion dependent thalassaemia with varying degrees of confidence were examined, alongside an additional child from Poundbury Camp with possible scurvy.

Micro-CT scans were taken of deciduous incisors, canines and molars and examined for changes in the dentine.

No teeth showed an 'iris-like' appearance. Instead, interglobular dentine (IGD) was identified in children from Poundbury Camp, Dorset and Butt Road, Colchester, previously identified with probable thalassaemia. No pathological changes were seen in the remaining children. There were two examples where postmortem changes were identified in one tooth but not in the additional teeth from the same individual.

While this research rejects the idea that 'iris-like' changes to the dentine are a diagnostic feature of beta-thalassaemia, it flags the possibility of a link between IGD development and the disease.

Previously identified 'iris-like' changes due to beta-thalassaemia are unlikely to present in deciduous incisors due to timing of disease onset and therefore can not be used as a diagnostic feature. The results also highlight that different teeth within the same individual can display varying taphonomic changes.

The sample size is small, and no individuals had thalassaemia confirmed by ancient DNA analysis, although the 'rib-within-rib' radiographic sign present in one individual from Poundbury Camp, is highly diagnostic.

Micro-CT scanning teeth of individuals with known beta-thalassaemia could further investigate if IGD development is associated with disease progression.