Étude comparative des caractéristiques physicochimiques de substituts osseux phosphocalciques

Bone substitutes are more and more used in bone surgery for their biologic safety, clinic efficiency and facility to synthesize. However many devices are actually marketed which are not similar according to their theoretical composition. We did not find any comparative physicochemical or clinical study which allows to evaluate them. The aim of this study is to compare with the same analysis methods the physicochemical properties of 14 marketed materials (blocs and granules). X-ray diffraction and infrared spectroscopy were used for components determination. Secondary electron microscopy (SEM) was performed for porosity measurements and micro-indentation method was applied to determine the elastic limits. At last a dissolution test was performed. The results have shown that the composition is likely those claimed by manufacturers excepted for one material. However mineral impurities were detected in some substitutes. All materials are not macroporous (some of them have macroporosity less than 30%). Moreover we observed a large diversity between materials (macroporosity comprised between 30 and 60%). Micro-indentation method allowed to characterize three groups of substitutes (elastic limit lower than 10 MPa, comprised between 30 and 40 MPa, upper 100 MPA). Results from dissolution experiments did not show any correlation with theoretical composition. This study shows that all materials have a nearby composition. The macroporosity and mechanical properties are not similar according the several studied substitutes. However these last properties have a great influence on the osseous integration and it would be on interest to perform some clinical comparative study with these bone substitutes.