Abstract: Porous granules without organic residues were produced from bovine medular anorganic bone. Sample showed carbonate content and crystalline order similar to natural bone. The cytotoxicity of anorganic bovine xenograft (Ossĕus®) was valuated from fibroblasts (1.5x104/cm2) cultured in serial diluted extract (0 – 100%) of Ossĕus plus 10% of fetal bovine serum (FBS). Pure
extract (100%) reduced in 15% the number of viable cells (p<0.05, ANOVA, Tukey test) indicating very low cytotoxicity. Samples were implanted in the subcutaneous tissue of mice in order to
evaluate tissue reaction. An organized connective tissue in contact to the granules was observed nine weeks after implantation. The anorganic bovine xenograft (Ossĕus®) was biocompatible and its behavior and osteoconduction potential should be evaluated in bony defects.
Abstract: The biological response following subcutaneous and bone implantation of β-wollastonite(β-W)-doped α-tricalcium phosphate bioceramics in rats was evaluated. Tested materials were: tricalcium phosphate (TCP), consisting of a mixture of α- and β-polymorphs; TCP doped with 5 wt. % of β-W (TCP5W), composed of α-TCP as only crystalline phase; and TCP doped with 15 wt. % of β-W (TCP15), containing crystalline α-TCP and β-W. Cylinders of 2x1 mm were implanted in tibiae and backs of adult male Rattus norvegicus, Holtzman rats. After 7, 30 and 120 days, animals were sacrificed and the tissue blocks containing the implants were excised, fixed and processed for histological examination. TCP, TCP5W and TCP15W implants were biocompatible but neither bioactive nor biodegradable in rat subcutaneous tissue. They were not osteoinductive in connective tissue either. However, in rat bone tissue β-W-doped α-TCP implants (TCP5W and TCP15W) were bioactive, biodegradable and osteoconductive. The rates of biodegradation and new bone formation observed for TCP5W and TCP15W implants in rat bone tissue were greater than for non-doped TCP.
Abstract: Unidirectional porous hydroxyapatite (UDPHAp) was developed which has microstructure in that cross sectionally oval pores 100 ~ 300µm in diameter penetrate through the material, and that is suitable for osteogenesis and angiogenesis.The porosity of the UDPHAp was 75 % and the compression strength was 14 MPa. A cortical bone defect was made at proximal tibia of Japanese white rabbit, and a trapezoidal prisms shaped UDPHAp was implanted. By histlogical evaluation, 2 weeks after implantation, new bone and new capillary was observed inside UDPHAp. Twelve weeks after implantation, new bone formation was observed in 41.6 % of the porous area. The results of this study suggest a great possibility of utilizing it in actual clinical setting as a bone substitution.
Abstract: Biomaterials for treatment of bone defects have been studied for a long time. Alloplastic materials, mainly hydroxyapatite (HA), are under intense investigation due to its biocompatibility and osteoconductive properties. The HA can be modified by the incorporation of bivalent cations as Zn2+ known as a positive effectors for bone repair. The purpose of this study was to evaluate comparatively the effectiveness of 5% zinc-containing hydroxyapatite (ZnHA) in the treatment of critical size defect (CSD) in rat’s calvaria. CSD (8mm diameter) created in the skull of forty-five Wistar rats were filled with autogenous bone, HA and ZnHA. Skulls harvested after 30, 90 and 180 days were submitted to histological processing for paraffin embedding. Sections of 5 µm-thick stained with hematoxylin and eosin (HE) allowed histomorphometric analysis. The area of neoformed bone increased (p<0.001) from 30 to 180 days irrespective to treatment groups. ZnHA and the control group showed a large at 180 days but no significant difference compared to HA. Therefore, we concluded that both biomaterials are biocompatibles and osteoconductors, promoting new bone formation and apposition of bone on the surface throughout the periods and the addition of zinc improved the osteogenesis.
Abstract: Bioactive ceramics such as β-tricalcium phosphate (β-TCP) promote and enhance biological fixation. Ceramics with a porous interconnected structure are suited for facilitation of bony ingrowth. An interconnected pore system with pore diameters in excess of 100 µm is required for cell penetration, tissue ingrowth, vascularization and nutrient delivery to the centre of the regenerating tissue. Human osteoblasts were cultured on the surface of a ceramic. In an in-vivo study, β-TCP samples with a porous interconnected structure were implanted into the femur of sheep and then investigated 6 weeks after operation. Histological analysis was performed on the area surrounding the implant. An indentation test was performed to complete failure of the bone/ceramic compound. Linear load, peak load and stiffness were recorded. All cylinders were found to be biocompatible and osteoconductive. Bone was more abundant in the outer ring than in the rest of the cylinder. The ceramic/bone compound was of low mechanical grade.
Abstract: The objective of this study was to physico/chemically characterize a commercially available and a newly developed Bioglass and also to evaluate their degradation properties. Materials and Method: Two bioresorbable glasses were utilized, a bioglass synthesized at Chemical Engineering College (University of São Paulo, Lorena, São Paulo) (BG1), and the other bioglass utilized was Biogran (BG2) (3i Implant Innovations, Brazil). Particles size distribution histograms were developed for both materials, and then they were characterized by Scanning Electron Microscopy (SEM), X-ray diffraction (XRD) and Fourier Transform Infrared (FTIR) before and after immersion in simulated body fluid (SBF) for 30, 60, and 90 days. Results: The particle size distribution showed that the mean particle diameters at 10%, 50%, and 90% of the total volume were 17.65, 66.18, and 114.71 µm for BG1, and 354.54, 437.5, 525.00 µm for BG2. SEM images of BG1 showed that the as-received material had a rough surface and as the time of degradation elapsed, this surface became smooth. The images of BG2 showed that the as-received material also had a rough surface, and after immersion in SBF, the material’s crystalline content/morphology could be observed. The X-ray diffraction recorded that BG1 showed a silica peak, not seen at BG2. FTIR revealed that both bioglasses were of similar composition, except for the CO3-carbonate minor peak, present at the BG2 sample. Conclusions: 1. The particle size distribution showed a polydispersed pattern for both materials. 2. The material suffered degradation, and the decomposition increased as a function of immersion in SBF. 3. Both bioglasses had similar composition.