Partners in Postmortem Interval Estimation: X-ray Diffraction and Fourier Transform Spectroscopy

Abstract

The postmortem interval (PMI) is difficult to estimate in later stages of decomposition. There is therefore a need to develop reliable methodologies to estimate late PMI. This study aims to assess whether there is a correlation between changes in the mineral composition of human teeth and the estimation of PMI. X-ray diffraction (XRD) and attenuated total reflection Fourier transform infrared (ATR-FTIR) spectroscopy techniques were performed to address this challenge. Forty healthy human teeth obtained from odontological clinics were stored at different times (0, 10, 25, 50 years; N = 10/group). XRD and ATR-FTIR parameters related to the structure and composition of teeth were studied. Our results showed that the crystallinity index, crystal size index, mineral-to-organic matrix ratio (M/M) and carbonate/phosphate ratio (C/P) had the strongest association with PMI. For larger PMIs, there was a significant increase in crystallinity, crystal size and M/M ratio, while the C/P ratio showed a specific decrease with increasing PMI. According to our results, the parameters of crystallinity, crystal size, M/M ratio and C/P ratio can be considered highly accurate in determining a PMI of 10 years of data; crystallinity and mineral maturity can be considered useful in determining a PMI of 25 years; and crystallinity and mineral maturity can be considered highly accurate in determining a PMI of 50 years. A particular XRD index was identified as the most suitable parameter to estimate PMI: crystallinity. The joint use of XRD and ATR-FTIR analyses could be a promising alternative for dating human teeth.

Comparison of Mid-Infrared Handheld and Benchtop Spectrometers to Detect Staphylococcus epidermidis in Bone Grafts

“…Table 2 concisely overviews the essential parameters scrutinized in MIR spectra. These parameters encompass the intensities (I) of the most influential bands, culminating in single-band and multiple-band ratios [ 54 , 55 , 57 , 58 , 59 ]. They serve as markers that furnish precise diagnostic data on infections that impact human bones, as depicted in Figure 4 .…”

“…Spectral Parameters: The diagnostic parameters were studied using peak intensity (I) [ 54 , 55 , 56 , 57 , 58 , 59 ]. The determination of intensities was made effortless through an Excel spreadsheet that handles spectroscopic and chromatographic data [ 60 ].…”

Enhancing Bone Infection Diagnosis with Raman Handheld Spectroscopy: Pathogen Discrimination and Diagnostic Potential

“…Frequency shifts and background subtraction were not performed and were necessary. To study diagnostic parameters, peak intensity (I) [ 69 , 70 , 71 , 72 , 73 , 74 ] was analyzed with the help of an Excel spreadsheet that manages both spectroscopic and chromatographic data [ 75 ]. Subsequent to selecting the desired peak from the “Output” section, the baseline was adjusted by subtracting a linear equation derived from the x1:y1 and xn:yn values.…”