β-Tricalcium Phosphate Interferes with the Assessment of Crystallinity in Burned Skeletal Remains

Figure 5

A detailed comparison of different FT-IR curves collected for three different bioapatite specimens: (a) CC/NI/18_vertebra II, (b) T4 tooth, and (c) T1 tooth with the corresponding XRD Rietveld phase evaluation. The distortions of ATR-IR phosphate band with respect to the conventional expected behavior are strictly related to the amount of the β-TCP phase which was stimulated by the high-temperature treatment. Particularly, when the presence of β-TCP is massive (≥20%), the band appears strongly deformed due to the overlap with the ν₄ band of bioapatite (see the deformation of the peak at 563 cm⁻¹), and also, the CI calculation is problematic.

(a) CC/NI/18_vertebra II

(b) T4 tooth

(c) T1 tooth