Periapical lesions in hominids: Abscesses on the maxilla of a 2 million‐year‐old early Homo specimen
Periapical lesions can develop after exposure of a tooth's pulp chamber and are commonly associated with heavy crown wear, trauma, or caries. In this study, maxilla and mandible fragments from the South African fossil hominin collections were studied, including specimens assigned to Homo naledi, Paranthropus robustus, Australopithecus africanus, and early Homo. Gorilla gorilla gorilla, Pan troglodytes, and Homo sapiens were also studied for comparative purposes. Only one fossil hominin specimen displayed voids consistent with periapical lesions. The specimen, SK 847, is described as early Homo and has been dated to 2.3–1.65 Ma. There is one definite periapical lesion and likely more with post‐mortem damage, all on the anterior aspect of the maxilla and associated with the incisors. The lesions originate from the apices of the incisor roots and are therefore unlikely to represent a systemic disease such as multiple myeloma. The one well‐preserved lesion was likely an abscess rather than a cyst or granuloma, with a rounded thickened rim around the lesion. These lesions in an early Homo specimen highlight that this individual used their anterior dentition extensively, to the point that the pulp chambers were exposed on multiple teeth. This is one of the earliest hominin examples of periapical lesions and shows that this individual was able to cope with potentially several concurrent abscesses, clearly surviving for an extended period. Periapical lesions are relatively common in the great ape (P. troglodytes: 1.99%; G. gorilla gorilla: 1.86%) and human samples (2.50%) but absent in large samples of P. robustus and A. africanus (n = 0/373 teeth). Therefore, this finding adds additional information to the history of dental pathology in our genus and also suggests that other hominin genera may have been less susceptible to dental abscesses, potentially relating to dietary or behavioural differences.