Thermal Disruption of the Physical and Chemical Properties of Bone

  • Andrew Mark Houston

Student thesis: Doctoral ThesisDoctor of Science

Abstract

Bone undergoes a multitude of heat induced-changes when exposed to extreme temperature. Understanding these heat-induced changes is essential to forensic practitioners to enable them to explain thermal changes to bone. This study aims to determine the heat-induced changes that fleshed and defleshed porcine ribs experience due to peak exposure temperatures of 0-1000oC, for durations of up to 1-hour, using Fourier-transform infrared spectrometry (FTIR), colour assignment, and microcomputed tomography (µCT).

In this study the seven peaks in the FTIR spectra of porcine ribs; 1410 cm-1 (ѵ3CO32-), 1445 cm 1 (CH2 bend), 1548 cm-1 (amide[II]), 1634 cm 1 (amide[I]), 2850 cm 1 (CH2 symmetric stretch), 2930 cm-1 (CH2 asymmetric stretch), and 3500 cm-1 (ѵOH), were quantified by ratio comparison with the inorganic peak at 1012 cm-1 (ѵ3PO43- asymmetric stretch), to analyse their response to different exposure conditions. Subsequently, the same porcine ribs were evaluated using colour assignment methodologies (qualitative colour, burn code, and the Munsell colour chart) to assess their reliability, as well as ascertaining whether they could provide further distinction between exposures and durations. Finally, the ability of µCT to observe heat-induced changes to bone volume fraction (BV/TV), bone specific surface (BS/BV), trabecular thickness (Tb.Th), trabecular number (Tb.N), and trabecular spacing (Tb.Sp) of trabecular bone in fleshed porcine ribs was investigated.

This study concluded that FTIR could distinguish between exposure conditions of up to 500oC, except for durations of 60 minutes which reduced this to 400oC. However, FTIR analysis was unable to confidently attribute exposure conditions in isolation. Similarly, colour methodologies could not attribute exposure conditions alone but did provide a second corroborating factor alongside FTIR. Colour assignments also highlighted the benefits of using quantitative methods, over qualitative methods, due to their lower inter and intraobserver error. The utility of Micro-CT for assessing the heat induced changes to trabecular characteristics in fleshed porcine ribs was also confirmed.
Date of Award2021
Original languageEnglish
SupervisorLucina Hackman (Supervisor) & Craig Cunningham (Supervisor)

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