An experimental study of the effects of heating and burning on the hard tissues of the human body and its implications for anthropology and forensic science

An understanding of heat-induced transformation of hard tissue is vital before a full interpretation of burned human remains can be successfully achieved. While some studies have examined this issue a lack of understanding continues to exist within the discipline. This study addresses a number of fundamental questions concerning the effect of heat on bone using a broad spectrum of analytical techniques. These include experimental burning, radiography, scanning electron microscopy, x-ray diffraction and for the first time mercury intrusion porosimetry and small angle x-ray scattering. These methods assisted in the study of heat-induced transformations in bone colour, mechanical strength, microstructure and dimension. Samples of modem sheep (n=60), modem human permanent and deciduous teeth and archaeological human permanent teeth (n=128) were analysed resulting in 5440 data points. An holistic experimental approach was undertaken exploring the bi-variable impact of heating temperature and duration of burning. Subsequent heat-induced bone changes included the progression of colour from natural through to blue-white, the significant loss of weight, the reduction in mechanical strength, the development of distinct fracture patterns, alterations in the microscopic porosity, substantial alterations in crystalline structure and the reduction and expansion in size. Collation and integration of this information demanded a fundamental revision of the four stages of heat-induced degradation of bone previously presented by Mayne Correia (1997) and Thompson (1999). The results of this study suggested that new approaches to the analysis of burned and cremated human remains within the forensic and archaeological arenas should be adopted. An examination of the role of the forensic anthropologist in mass fatality incidents alongside a retrospective study of regional fire-related deaths provides the context for this doctoral research.