title: The circles of life: age at death estimation in burnt teeth through tooth cementum annulations.
abstract: Age at death estimation in burnt human remains is problematic due to the severe heat-induced modifications that may affect the skeleton after a burning event. The objective of this paper was to assess if cementochronology, which focuses on the cementum incremental lines, is a reliable method of age estimation in burnt remains. Besides the classical approach based on the counting of incremental lines, another approach based on the extrapolation of incremental lines taking into account the cement layer thickness and the incremental line thickness was investigated. A comparison of the performance of the two techniques was carried out on a sample of 60 identified monoradicular teeth that were recently extracted at dentist offices and then experimentally burnt at two maximum temperatures (400 and 900 °C). Micrographs of cross-sections of the roots were taken via an optical microscope with magnification of ×100, ×200 and ×400. Incremental line counting and measurements were carried out with the ImageJ software. Age estimation based on incremental line counting in burnt teeth had no significant correlation with chronological age (p = 0.244 to 0.914) and led to large absolute mean errors (19 to 21 years). In contrast, age estimation based on the extrapolation approach showed a significant correlation with known age (p = 0.449 to 0.484). In addition, the mean absolute error of the latter was much smaller (10 to 14 years). The reason behind this discrepancy is the heat-induced dimensional changes of incremental lines that affect their visibility and individualization thus complicating line counting. Our results indicated that incremental lines extrapolation is successful at solving this problem and that the resulting age estimation is much more reliable.
authors: Center for Functional Ecology, Laboratory of Forensic Anthropology, Department of Life Sciences, University of Coimbra, 3000-456, Coimbra, Portugal. ines.olsantos@gmail.com.|Research Centre for Anthropology and Health (CIAS), Department of Life Sciences, University of Coimbra, Calçada Martim de Freitas, 3000-456, Coimbra, Portugal. ines.olsantos@gmail.com.
authors: Inês
authors: I
authors: Oliveira-Santos
authors: Department of Life Sciences, University of Coimbra, Calçada Martim de Freitas, 3000-456, Coimbra, Portugal.
authors: Márcia
authors: M
authors: Gouveia
authors: Center for Functional Ecology, Laboratory of Forensic Anthropology, Department of Life Sciences, University of Coimbra, 3000-456, Coimbra, Portugal.|Department of Life Sciences, University of Coimbra, Calçada Martim de Freitas, 3000-456, Coimbra, Portugal.
authors: Eugénia
authors: E
authors: Cunha
authors: Center for Functional Ecology, Laboratory of Forensic Anthropology, Department of Life Sciences, University of Coimbra, 3000-456, Coimbra, Portugal.|Research Centre for Anthropology and Health (CIAS), Department of Life Sciences, University of Coimbra, Calçada Martim de Freitas, 3000-456, Coimbra, Portugal.|Archaeosciences Laboratory, Directorate General for Cultural Heritage and LARC/CIBIO/InBIO, Rua da Bica do Marquês 2, 1300-087, Lisbon, Portugal.
authors: David
authors: D
authors: Gonçalves
mesh_terms: D000328:Adult; D000366:Age Determination by Teeth / Q000379:methods*; D000368:Aged; D000369:Aged, 80 and over; D025021:Cementogenesis; D003739:Dental Cementum / Q000473:pathology*; D005260:Female; D005390:Fires; D005553:Forensic Dentistry; D006801:Humans; D008297:Male; D008853:Microscopy; D008875:Middle Aged; D055815:Young Adult
keywords: Cementochronology; Dental age estimation; Forensic anthropology; Heat-induced changes; Incremental lines