A unique case of mandibular osteomyelitis arising from tooth germ infection in a 7,000-year-old infant from Siberia

Excavations from a 7,000-year-old mortuary site in the Lake Baikal region of Siberia, Russian Federation, revealed an infant with osteomyelitis of the mandible. The lesion exhibits deformation of the anterior mandibular base, an extra-oral cloaca, and new periosteal bone layers on the corpus. Entry of oral microorganisms was likely via the deciduous left canine, with infection then concentrated around the forming permanent canine tooth germ. This infection route is not widely documented in paleopathology and the pathogenicity of oral microorganisms is discussed. This unique case is one of the oldest examples of infant osteomyelitis of the jaws, adding to our understanding of the antiquity and development of infectious diseases in humankind. Knowledge of diseases is furthered by their evidence in ancient peoples. Osteomyelitis of the mandible arising from a tooth germ infection is relatively rare in modern populations (Baltersperger and Eyrich, 2009) and is not widely reported in paleopathology literature. This case report presents what is argued to be a 7,000-year-old case of mandibular osteomyelitis with accompanying new periosteal bone in an infant from a mortuary site named Shamanka II in south-central Siberia, Russian Federation. The lesion’s hypervascular appearance is rather distinctive, with a small cloaca and extensive, irregular periosteal bone deposits on the mandibular corpus. Osteomyelitis of the jaws differs from that of the long bones because of the former’s unique tooth bearing function and connection to the oral cavity and periodontal membrane. Thus, local immunological and microbiological factors are important in the disease’s etiology and pathogenesis (Baltensperger and Eyrich, 2009; Slootweg, 2010). Immature teeth are especially susceptible to infection because of incomplete root formation with open apices and large canal sizes (Huang, 2009). Further, because common nonpathogenic oral microorganisms have the potential to cause infection (Willet et al., 1991), osteomyelitis is possible even in the absence of carious or periodontal lesions, as is argued for this case. When considering paleopathology of the jaws it should be kept in mind that oral microbes have great antiquity and thus the potential for an endodontic infection route has been present for many millennia. Therefore, this case report is useful for dental anthropologists and paleopathologists for several reasons: a) in presenting an ancient case of mandibular osteomyelitis of unique appearance, b) in demonstrating the presence of the tooth germ infection route, even in the absence of carious and periodontal infection, and c) in illustrating the importance of considering the pathogenicity of otherwise normal oral microor-