This study was developed based on in vivo investigation of microporous granular biomaterials based on calcium phosphates, involving matrices of β-tricalcium phosphate (β-TCP), hydroxyapatite (HA), biphasic compositions of both phases and a control group. The physicochemical characterization of materials was carried out by X-Ray diffraction (DRX) and mercury porosimetry. Biodegradability, bioactivity and neoformation processes were investigated by Raman spectroscopy, scanning electron microscopy (SEM) and polarized light conducted on biopsies obtained from in vivo tests for periods of 90 and 180 days. These were performed to evaluate the behavior of granular microporous compositions in relation to bone neoformation. Through the performance obtained from in vivo assays, excellent osseointegration and bone tissue neoformation were observed. The results are encouraging and show that the microporous granular biomaterials of HA, β-TCP and biphasic compositions show similar results with perfect osseointegration. Architectures simulating a bone structure can make the difference between biomaterials for bone tissue replacement and repair.

The present research paper centers on physicochemical characterization of six nanostructured alloplastic bone substitutes developed at Santa Catarina State University (UDESC Brazil). In addition to identifying the main phases, the focus was to measure the morphological and microstructural features, which are believed to be crucial for controlling and guiding biological and molecular events. The studied samples exhibited rounded granules measuring 200μm 10(PO4)6(OH)2] was found as main phase for HAp, BCP and HAp/Al2O3 biomaterials. For HAp/TiO2n, HAp/SiO2n and β-TCP, the major phase was beta tricalcium phosphate [Ca3(PO4)2-β]. The results demonstrate that the presence of a second phase of nanometer order, at a hydroxyapatite bioceramic matrix, may modify the surface diffusion of the grains and the phase transformation kinetics of hydroxyapatite and beta tricalcium phosphate at temperatures up to 1100°C.

Calcium phosphates biocements are biomaterials that present crystallographic and mineralogical characteristics similar to human skeletal structure. This has led to the development of new calcium phosphates biomaterials for biomedical applications, especially biomaterials for repairing defects and bone reconstruction. Calcium phosphates biocements are a promising alternative in biomedical applications, for they are easy to mold, they have good wettability, hydration and hardening capacity during its application in biological environment. This work aimed at the synthesis of hydrated calcium phosphates powder, precursor to late biocements development. Three calcium phosphates compositions were produced via CaCO3/phosphoric acid reactive method in the ratios Ca/P = 1,5; 1,6 e 1,67 molar. The presented results are associated to hydrated powder morphology and synthesis process control. Field Electronic Microscope helped with the morphological characterization of the powders, Fourier Transformed Infrared Spectroscopy (FTIR) gave support to the identification of H2O e PO43- grouping vibrational bands and x-ray diffractometry (XRD) served on crystallographic characterization of hydrated calcium phosphates. The work showed that for the different powder compositions the hydrated calcium phosphate phase is formed by clustered fine particles. This demonstrated that the chosen synthesis method permits the obtaining nanoparticles of hydrated calcium phosphates, precursors for later biocement production.

Bioceramics of calcium phosphate, obtained from natural raw materials, are promising as bone substitutes because they exhibit crystallographic similarity with the bone tissue. This work deals with the sintering and characterization of calcium phosphate biomaterials from fossilized calcareous shells. Four compositions of biomaterials were prepared with Ca/P molar ratio ranging from 1.4 to 1.67. They were synthesized using a wet method and calcined at 900°C/2h providing calcium phosphate powder, then compressed into a metallic mould. The samples obtained from this compression were sintered at 1200oC for 2h. The biomaterials recovered from sintering were subjected to a microstructural characterization by scanning electron microscopy [SE and by X-ray diffraction [XR. Mechanical properties were determined by compression tests. Finally, the Arthur method was used for determining the hydrostatic density and open porosity from these biomaterials. The value of fracture strength was between 54 and 84 MPa for compositions 1.5, 1.67 and 1.6 molar and for composition 1.4 molar about 328 Mpa. The results also showed was the amount of open porosity which ranged between 35 and 54% with increasing Ca/P molar ratio. These studies demonstrate that the production of biomaterials from fossilized calcareous shells may be a new alternative to the production of biomaterials for bone reconstruction.