Effect of the calcination temperature on the composition and microstructure of hydroxyapatite derived from human and animal bone

Abstract

The present work focus the study of cortical bone samples of different origins (human and animal) subjected to different calcination temperatures (600, 900 and 1200 8C) with regard to their chemical and structural properties. For that, not only standard techniques such as thermogravimetric analysis, Fourier transform infrared spectroscopy, X-ray diffraction and scanning electron microscopy were used but also mercury intrusion porosimetry. The latter technique was applied to evaluate the effects of the temperature on the microstructure of the calcined samples regarding porosity and pore size distribution.Although marked alterations in structure and mineralogy of the bone samples on heating were detected, these alterations were similar for each specimen. At 600 8C the organic component was removed and a carbonate apatite was obtained. At 900 8C, carbonate was no longer detected and traces of CaO were found at 1200 8C. Crystallinity degree and crystallite size progressively increased with the calcination temperature, contrary to porosity that strongly decreased at elevated temperatures. In fact, relatively to the control samples, a significant increase in porosity was found in samples calcined at 600 8C (reaching values around 50%). At higher temperatures, a dramatic decrease was observed, reaching, at 1200 8C, values comparable to those of the non-calcined bone. #

Comparison of a xenogeneic and an alloplastic material used in dental implants in terms of physico-chemical characteristics and in vivo inflammatory response

“…The measured values seem to be consistent with the samples composition: in the case of Osteobiol®, is inferior to that of hydroxyapatite (3.16 g cm -3 ) [39], as expected for a collagenated sample; as for Bonelike® particles, a smaller value than that of hydroxyapatite was also anticipated due to its constitution (-and -TCP as secondary phases with theoretical densities of 2.86 g cm -3 and 3.07 g cm -3 , respectively [40]). …”

“…As expected, the FTIR spectrum of Osteobiol® (Figure 7b) is very similar to the ones registered from porcine or human bone samples [39], displaying the typical bands of collagen (bands of amide I (1660 cm -1 ) and amide II (1550 cm -1 ) [41]) and of hydroxyapatite (the stretching vibrations of the PO 4 3-group). Contrary to that of Bonelike®, in this spectrum are also visible a few bands attributed to the stretching vibrations of the carbonate group (the  3 mode, appearing as a double band between 1400 cm -1 and 1500 cm -1 , and the  2 mode band at 878 cm -1 ), which reveals the carbonated (natural) structure of the hydroxyapatite present in this graft [43].…”

Adsorptive Removal of p-Nitrophenol from Aqueous Solution by Bone Char: Equilibrium and Kinetic Studies

“…The Ca:P ratio in the bone char (1.78) is close to the ratio (1.65) reported for hydroxyapatite in cow bones [1,27]. This result corroborates reports from previous studies which suggest that carbonization of bones between 200 °C and 600 °C has little influence on the Ca/P ratio of hydroxyapatite [28].…”

Characterization of Bone and Bone-Based Graft Materials Using FTIR Spectroscopy

“…A recent study concerning cortical bone samples of different origins (human and animal) subjected to different calcination temperatures (600, 900 and 1200 ºC) revealed that the calcination temperature highly affects the properties of the bone samples (Figueiredo et al, 2010). As expected, higher temperatures led to more pure forms of hydroxyapatite, with higher crystallinity degrees and larger crystallite sizes and a less porous structure.…”