Heat-induced dimensional changes in bone and their consequences for forensic anthropology.

An understanding of heat-induced transformation of hard tissue is vital before a full interpretation of burned human remains can be successfully achieved. Samples of modem sheep (n = 60) were analyzed resulting in 5440 data points. An experimental approach was undertaken that explored the bi-variable impact of heating temperature and duration of burning. Subsequent heat-induced bone changes included the progression of color 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 reduction and expansion in size. Collation and integration of this information demanded a revision of the four stages of heat-induced degradation of bone previously presented by Mayne Correia (1) and Thompson (2). The results demonstrate that heat-induced shrinkage is also accompanied by expansion and that both can be statistically significant. This suggests that anthropological techniques applied to burned bone will likely be detrimentally affected and accuracy will be reduced.