Forensic age estimation of living subjects has become increasingly important in recent years. One main criterion for dental age estimation in the relevant age group is the evaluation of third molar mineralization. In the present study, we determined the stages of third molar mineralization in 347 female and 258 male First Nations people of Canada aged 11 to 29 years based on radiological evidence from 605 conventional orthopantomograms. The results presented here provide useful data on the mineralization stages of third molars that can be used for forensic estimation of the minimum and most probable ages including the range of scatter of investigated persons.

We report on dental and mandibular pathology in Labidosaurus hamatus, a 275 million-year-old terrestrial reptile from North America and associate it with bacterial infection in an organism that is characterized by reduced tooth replacement. Analysis of the surface and internal mandibular structure using mechanical and CT-scanning techniques permits the reconstruction of events that led to the pathology and the possible death of the individual. The infection probably occurred as a result of prolonged exposure of the dental pulp cavity to oral bacteria, and this exposure was caused by injury to the tooth in an animal that is characterized by reduced tooth replacement cycles. In these early reptiles, the reduction in tooth replacement is an evolutionary innovation associated with strong implantation and increased oral processing. The dental abscess observed in L. hamatus, the oldest known infection in a terrestrial vertebrate, provides clear evidence of the ancient association between terrestrial vertebrates and their oral bacteria.

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