Beta-tricalcium Phosphate Research Articles

Výsledky léčby parodontálních kostních chobotů kombinací kalcium sulfátu a beta trikalcium fosfátu

Výsledky léčby parodontálních kostních chobotů kombinací kalcium sulfátu a beta trikalcium fosfátu

Bone regeneration using composite non-demineralized xenogenic dentin with beta-tricalcium phosphate in experimental alveolar cleft repair in a rabbit model

BackgroundAlveolar cleft repair is performed via bone grafting procedure to restore the dental arch continuity. A suitable bone substitute materials should possess osteoinductive and osteoconductive properties, to promote new bone formation, along with a slowly resorbable scaffold that is subsequently replaced with functionally viable bone. Calcium phosphate biomaterials have long proved their efficacy as bone replacement materials. Dentin in several forms has also demonstrated its possibility to be used as bone graft replacement material in several studies. The purpose of this study was to evaluate bone regeneration pattern and quantify bone formation after grafting pre-established experimental alveolar clefts defects model in rabbits using composite xenogenic dentin and β-TCP in comparison to β-TCP alone.MethodsUnilateral alveolar cleft defects were created in 16 New Zealand rabbits according to previously described methodology. Alveolar clefts were allowed 8 weeks healing period. 8 defects were filled with β-TCP, whereas 8 defects filled with composite xenogenic dentin with β-TCP. Bone regeneration of the healed defects was compared at the 8 weeks after intervention. Quantification of bone formation was analyzed using micro-computed tomography (µCT) and histomorphometric analysis.ResultsµCT and histomorphometric analysis revealed that defects filled with composite dentin/β-TCP showed statistically higher bone volume fraction, bone mineral density and percentage residual graft volume when compared to β-TCP alone. An improved surgical handling of the composite dentin/β-TCP graft was also noted.ConclusionsComposite xenogenic dentin/β-TCP putty expresses enhanced bone regeneration compared to β-TCP alone in the reconstruction of rabbit alveolar clefts defects.

Chronic infection and infected non-union of the long bones in paediatric patients: preliminary results of bone versus beta-tricalcium phosphate grafting after induced membrane formation.

Chronic infection (CO) and infected non-union of the long bones are relatively rare conditions in paediatric patients. Large bone defects secondary to these conditions can be managed with the induced membrane technique. The technique requires grafting of the bone void, although it is not yet established what bone substitute is the best option. The aim of this work was to evaluate the outcome and efficacy of treatment in children with CO and infected non-union of the long bones using the induced membrane technique and bone (BG) versus beta-tricalcium phosphate (BTP) grafting. Eight skeletally immature patients with CO and infected non-union of the long bones were treated surgically between 2010 and 2017 by a combination of resection of necrotic infected bone, debridement of surrounding soft tissue, osteosynthesis using a stable internal fixation when needed, and application of antibiotic-laden cement (ALC) spacer inducing new membrane before final bone reconstruction with bone substitutes: BTP in five cases, BG (allograft and/or autologous graft) in three cases. A second surgical step, once inflammatory markers had normalized, consisted of ALC spacer removal, application of BG or BTP graft and concomitant stable osteosynthesis, if needed, if this had not been done during the first surgical stage. All the patients underwent clinical, laboratory and imaging evaluation before and after surgery. Antibiotics were adjusted according to culture and sensitivity. Mean patient age at time of diagnosis was 13 ± four years (range, 4-16) and all had at least a 12-month follow-up (range 12-60). Estimated time for induced membrane formation was significantly shorter in patients treated with BTP compared with BG: 3±1 vs. 10±2 (p = 0.02). This result was confirmed by multivariate analysis (p = 0.044) taking into account adjustment for age of patients and time after initial surgery. Time of final union was about 5.5 ± 4.1months (range 2-66). At the last follow-up visit, bone had healed and all the patients had resumed daily living and sports activities. The induced membrane technique with BG or BTP graft can achieve bone healing in large bone defects secondary to CO and infected non-union in children and adolescents. The choice of bone substitute is important. Our preliminary results show graft integration and bone healing can be expected sooner if BTP is used as bone void filler.

3D–printed biphasic calcium phosphate scaffolds coated with an oxygen generating system for enhancing engineered tissue survival

Tissue engineering scaffolds with oxygen generating elements have shown to be able to increase the level of oxygen and cell survivability in specific conditions. In this study, biphasic calcium phosphate (BCP) scaffolds with the composition of 60% hydroxyapatite (HA) and 40% beta-tricalcium phosphate (β-TCP), which have shown a great potential for bone tissue engineering applications, were fabricated by a direct-write assembly (robocasting) technique. Then, the three-dimensional (3D)-printed scaffolds were coated with different ratios of an oxygen releasing agent, calcium peroxide (CPO), which encapsulated within a polycaprolactone (PCL) matrix through dip-coating, and used for in situ production of oxygen in the implanted sites. The structure, composition and morphology of the prepared scaffolds were characterized by different techniques. The oxygen release kinetics and biological investigations of the scaffolds were also studied in vitro. The results showed that oxygen release behaviour was sustained and dependant on the concentration of CPO encapsulated in the PCL coating matrix. It was also demonstrated that the coated scaffolds, having 3% CPO in the coating system, could provide a great potential for promoting bone ingrowth with improving osteoblast cells viability and proliferation under hypoxic conditions. The findings indicated that the prepared scaffolds could play a significant role in engineering of large bone tissue implants with limitations in oxygen diffusion.

Tentpole technique for bone regeneration in vertically deficient alveolar ridges: A prospective study

PurposeThe purpose of the study was to qualitatively and quantitatively assess bone regeneration potential of tentpole technique using beta tricalcium phosphate bone graft in vertically deficient alveolar ridges. Materials and MethodThis prospective study comprised of 20 patients with vertically deficient alveolar ridges, wherein thirty one implants were placed. Tenting of the soft tissue matrix was done using titanium screws and beta tricalcium phosphate synthetic bone graft was filled in the vertical defect. Clinical and radiographic assessment was done at 1, 3 and 6 months. Preoperative biochemical analysis of Osteopontin and RANKL was done and then reassesed at 3 months postoperative. Bone core collected at 6 postoperative months, while removal of screw, was analysed histologically. ResultsA significant gain in bone height of 2.87±0.79mm was seen at 6 months postoperative. All implants osseointegrated. Loosening of screw was seen in two patients.There was no postoperative wound dehiscence. Histologic analysis revealed new bone formation .There was no significant change in the levels of RANKL and Osteopontin at 3 months postoperative. ConclusionThis is a safe and effective technique for bone regeneration in vertically deficient alveolar ridges and has minimal complications. The regenerated bone has new and viable bone content and supports implant material. More studies with long term follow up are needed to assess the stability of bone after long term loading.

Surface characteristics of three commercially available grafts and adhesion of stem cells to these grafts.

Reconstruction of bone defects is often performed using bone autografts. However, limitations associated with the use of autografts led to the use of bone substitute materials. The purpose of this study was to compare the surface characteristics of three commercially available grafts namely allografts, xenografts and alloplasts. This in vitro study was conducted on beta-tricalcium phosphate (β-TCP) alloplast, a mixture of demineralized bone matrix and mineralized bone allograft (DBM&MBA) and natural bovine bone mineral (NBBM) xenograft. Presence of apatite groups on the surface of samples was assessed by X-ray diffraction (XRD) while the presence of functional groups was evaluated using Fourier transform infrared spectroscopy (FTIR). Also, dental pulp stem cells (DPSCs) were cultured on the surface of samples and their adhesion was evaluated under a scanning electron microscope (SEM). The FTIR showed a relatively similar pattern for NBBM and TCP samples and a different pattern in DBM&MBA. The results of XRD analysis also showed similarities between NBBM and TCP with sharper peaks than the DBM&MBA sample. The SEM micrographs showed that at 24 hours, no cell was detectable on the surface of NBBM sample; whereas, elongated cells were noted on the surface of TCP and DBM&MBA samples. The patterns of β-TCP and NBBM samples in XRD and FTIR spectroscopy showed high resemblance but they had different behaviors with respect to cell adhesion.

Autologous platelet-rich plasma induces bone formation of tissue-engineered bone with bone marrow mesenchymal stem cells on beta-tricalcium phosphate ceramics

BackgroundThe purpose of the study is to investigate whether autologous platelet-rich plasma (PRP) can serve as bone-inducing factors to provide osteoinduction and improve bone regeneration for tissue-engineered bones fabricated with bone marrow mesenchymal stem cells (MSCs) and beta-tricalcium phosphate (β-TCP) ceramics. The current study will give more insight into the contradictory osteogenic capacity of PRP.MethodsThe concentration of platelets, platelet-derived growth factor-AB (PDGF-AB), and transforming growth factor-β1 (TGF-β1) were measured in PRP and whole blood. Tissue-engineered bones using MSCs on β-TCP scaffolds in combination with autologous PRP were fabricated (PRP group). Controls were established without the use of autologous PRP (non-PRP group). In vitro, the proliferation and osteogenic differentiation of MSCs on fabricated constructs from six rabbits were evaluated with MTT assay, alkaline phosphatase (ALP) activity, and osteocalcin (OC) content measurement after 1, 7, and 14 days of culture. For in vivo study, the segmental defects of radial diaphyses of 12 rabbits from each group were repaired by fabricated constructs. Bone-forming capacity of the implanted constructs was determined by radiographic and histological analysis at 4 and 8 weeks postoperatively.ResultsPRP produced significantly higher concentration of platelets, PDGF-AB, and TGF-β1 than whole blood. In vitro study, MTT assay demonstrated that the MSCs in the presence of autologous PRP exhibited excellent proliferation at each time point. The results of osteogenic capacity detection showed significantly higher levels of synthesis of ALP and OC by the MSCs in combination with autologous PRP after 7 and 14 days of culture. In vivo study, radiographic observation showed that the PRP group produced significantly higher score than the non-PRP group at each time point. For histological evaluation, significantly higher volume of regenerated bone was found in the PRP group when compared with the non-PRP group at each time point.ConclusionsOur study findings support the osteogenic capacity of autologous PRP. The results indicate that the use of autologous PRP is a simple and effective way to provide osteoinduction and improve bone regeneration for tissue-engineered bone reconstruction.

A novel cytotherapy device for rapid screening, enriching and combining mesenchymal stem cells into a biomaterial for promoting bone regeneration

Bone defects are a common challenge in clinic, usually warranting bone grafts. However, current strategies to obtain effective graft materials have many drawbacks. Mesenchymal stem cell (MSC)-based therapy is a promising alternative. We designed an innovative appliance named the stem cell screen–enrich–combine(-biomaterials) circulating system (SECCS). In this study, 42 patients who required bone graft underwent SECCS-based treatment. Their bone marrow samples and beta-tricalcium phosphate (β-TCP) granules were processed in the SECCS for 10–15 minutes, to produce MSC/β-TCP composites. These composites were grafted back into bone defect sites. The results showed 85.53% ± 7.95% autologous MSCs were successfully screened, enriched, and seeded on the β-TCP scaffolds synchronously. The cell viability remained unchanged after SECCS processing. Clinically, all patients obtained satisfactory bone healing. Thus, without in vitro culture, the SECCS can produce bioactive MSC/β-TCP composites for bone regeneration during surgery. The SECCS represents a convenient, rapid, low-cost, and safe method for bone regeneration.

Preparation of a beta-tricalcium phosphate nanocoating and its protein adsorption behaviour by quartz crystal microbalance with dissipation technique

Beta-tricalcium phosphate (β-TCP) nanocoatings, which can be analysed using a quartz crystal microbalance with dissipation technique (QCM-D), were fabricated on a gold surface by electrophoretic deposition. The influences of electric field intensity and electrophoresis time were investigated. The adsorption behaviours of bovine serum albumin (BSA) and lysozyme (LSZ) on Au and β-TCP surfaces were observed in real time by QCM-D. The homogeneous β-TCP nanocoating with moderately sized particles on gold surface was fabricated at 25V/cm for 5min, and it met the requirements for the QCM-D experiment. The adsorption behaviour of BSA was different from that of LSZ, which was caused by the differences of protein properties. The adsorption quantity of BSA on a β-TCP surface was higher than that on a gold surface. However, the adsorption amount of LSZ on a β-TCP surface was lower than that on a gold surface. The electrostatic force was the major factor affecting the adsorption quantities of BSA and LSZ on Au and β-TCP surfaces based on the investigation of various factors. The findings reported here will be useful for understanding the mechanism of the interaction between biomaterials and proteins.

Effects of barium zirconium titanate on the properties of β-tricalcium phosphate bioceramics

In the present work, a new composite between β-tricalcium phosphate (a bioceramic material) and barium zirconium titanate (a ferroelectric material) were fabricated. Beta-tricalcium phosphate (β-TCP) powder was synthesized from egg shells while barium zirconium titanate powder was synthesized from metal oxide powders. The composites were fabricated by a solid-state reaction method. Effects of barium zirconium titanate on many properties of the composites were investigated. Barium zirconium titanate additive improves the electrical properties of the composites such as dielectric, ferroelectric and piezoelectric properties. Furthermore, the mechanical properties, such as hardness are improved by the additive. In-vitro bioactivity test suggests that β-tricalcium phosphate has a higher apatite forming ability as compared to the BZT. The obtained results indicate that the composites are a promising biomaterial candidate.

Implantation of Bone Marrow Stromal Cell Sheets Derived from Old Donors Supports Bone Tissue Formation.

The purpose of this study was to evaluate the osteogenesis ability of osteogenic matrix cell sheets (OMCS) derived from old donor cells. Bone marrow stromal cells (BMSC) were obtained from young (7-week-old) and old (1-year-old) Fischer344 rats donors and cultured with modified Eagle's medium (MEM group) alone or containing dexamethasone (Dex; 10nM) and ascorbic acid phosphate (AscP; 0.28mM) (Dex/AscP group). We prepared four in vitro experimental groups: (1) young MEM, (2) young Dex/AscP, (3) old MEM and (4) old Dex/AscP. Cell proliferation and osteogenic marker mRNA expression levels were evaluated in vitro. To assess bone formation in vivo, the cells of each group were combined with beta tricalcium phosphate (TCP) disks followed by implantation in recipient rats. The in vitro study showed significant differences in the mRNA expression of osteocalcin, ALP, and BMP2 between MEM and Dex/AscP groups. Bone formation following implantation was observed upon histological analyses of all groups. TCP combined with OMCS (OMCS/TCP group) resulted in enhanced bone formation compared to that following combination with BMSC (BMSC/TCP). The osteocalcin content of the OMCS/TCP group 4weeks after implantation was significantly higher than that in the BMSC/TCP construct for both young and old donors. The present study clearly indicated that OMCS could be generated from BMSCs of old as well as young donors using a mechanical retrieval method. Thus, through its usage of OMCS, this method may represent a potentially effective therapeutic option for cell-based therapy in elderly patients.

Pedicled Transplantation of Axially Vascularized Bone Constructs in a Critical Size Femoral Defect.

Axial vascularization represents a mandatory requirement for clinically applied larger scale vascularized bone grafts. The aim of this study was to combine the arteriovenous (AV) loop model in the rat with a critically sized femoral bone defect and to successfully transplant axially vascularized bone constructs into the defect. In Groups A and C, an AV loop together with a clinically approved hydroxyapatite and beta-tricalcium phosphate (HA/β-TCP) matrix, mesenchymal stem cells, and recombinant human bone morphogenetic protein 2 were implanted into a newly designed porous titanium chamber with an integrated osteosynthesis plate in the thighs of rats, whereas in Groups B and D, the same matrix composition without AV loop and, in Group E, only the HA/β-TCP matrix were implanted. After 6 weeks, the constructs were transplanted into a 10 mm femoral defect created in the same leg, in Groups A and C, under preservation of the AV loop pedicle. Group F served as a control group with an empty chamber. Ten days (Groups A and B) and 12 weeks (Groups C-F) after transplantation, the femora together with the constructs were explanted and investigated using computed tomography (CT), micro-CT, X-ray, histology, and real-time polymerase chain reaction (RT-PCR). Ten days after transplantation, Group A showed a maintained vascular supply leading to increased vascularization, cell survival in the scaffold center, and bone generation compared to Group B. After 12 weeks, there was no difference detectable among all groups regarding total vessel number, although Group C, using the AV loop, still showed increased vascularization of the construct center compared to Groups D and E. In Group C, there was still enhanced bone generation detectable compared to the other groups and increased bony fusion rate at the proximal femoral stump. This study shows the combination of the AV loop model in the rat with a critically sized femoral defect. By maintenance of the vascular supply, the constructs initially showed increased vascularization, leading to increased bone formation and bony fusion in the long term.

Bone Marrow Mononuclear Cells Combined with Beta-Tricalcium Phosphate Granules for Alveolar Cleft Repair: A 12-Month Clinical Study

Alveolar cleft is the most common congenital bone defect. Autologous iliac crest bone graft (ICBG) is the most widely adopted procedure for alveolar cleft repair, but the condition is associated with door-site morbidities. For the first time, this study used bone marrow mononuclear cells (BMMNCs) combined with beta-tricalcium phosphate (β-TCP) granules to repair alveolar bone defect. The effectiveness of this technique was compared with autologous ICBG after 12 months of follow-up. The bone formation volume was quantitatively evaluated by three-dimensional computed tomography and computer aided engineering technology. BMMNCs/β-TCP granule grafting was radiographically equivalent to ICBG in alveolar cleft repair. Although considerable resorption was observed up to 6 months after surgery, no significant differences were noted in the Chelsea score and bone formation volume between groups. These finding indicate that BMMNCs/β-TCP grafting is a safe and effective approach for alveolar bone regeneration.

Collagenous matrix supported by a 3D-printed scaffold for osteogenic differentiation of dental pulp cells

ObjectiveA systematic characterization of hybrid scaffolds, fabricated based on combinatorial additive manufacturing technique and freeze-drying method, is presented as a new platform for osteoblastic differentiation of dental pulp cells (DPCs). MethodsThe scaffolds were consisted of a collagenous matrix embedded in a 3D-printed beta-tricalcium phosphate (β-TCP) as the mineral phase. The developed construct design was intended to achieve mechanical robustness owing to 3D-printed β-TCP scaffold, and biologically active 3D cell culture matrix pertaining to the Collagen extracellular matrix. The β-TCP precursor formulations were investigated for their flow-ability at various temperatures, which optimized for fabrication of 3D printed scaffolds with interconnected porosity. The hybrid constructs were characterized by 3D laser scanning microscopy, X-ray diffraction, Fourier transform infrared spectroscopy, and compressive strength testing. ResultsThe in vitro characterization of scaffolds revealed that the hybrid β-TCP/Collagen constructs offer superior DPCs proliferation and alkaline phosphatase (ALP) activity compared to the 3D-printed β-TCP scaffold over three weeks. Moreover, it was found that the incorporation of TCP into the Collagen matrix improves the ALP activity. SignificanceThe presented results converge to suggest the developed 3D-printed β-TCP/Collagen hybrid constructs as a new platform for osteoblastic differentiation of DPCs for craniomaxillofacial bone regeneration.

Development of Biocomposite Based Anchor Screw System for Osteoporosis

With the recent advancements in arthroscopic surgery, the use of suture anchor has increased in the surgical treatment of rotator cuff tears. In the present study, we developed a suture anchor system for ligament reconstruction that can be applied to patients with osteoporosis or with low bone density. The anchor screws are made of biocomposites containing poly-L-lactic-co-glycolic acid (PLGA) and beta-tricalcium phosphate (β-TCP) in a 70:30 ratio. The suture anchor system consisted of medial and lateral screw. The lateral screw was designed in a hemicylindrical structure to prevent bone damage. The performance of the developed anchor screw was found to be greater than 402.5 N in a pull-out test.

Effects of ß-TCP scaffolds on neurogenic and osteogenic differentiation of human embryonic stem cells

Extracellular matrix (ECM) and adhesion molecules play crucial roles in regulating growth and differentiation of stem cells. The current study aimed to investigate the effects of beta-tricalcium phosphate (ß-TCP) scaffolds on differentiation and expression of ECM and adhesion molecules of human embryonic stem cells (hESCs). Undifferentiated hESCs were seeded on ß-TCP scaffolds and cell culture plates and cultured in growth and osteogenic medium for 21 days. Scanning electron microscopy (SEM) displayed adhesion and growth of hESCs on the porous ß-TCP scaffolds. Histological analysis, immunohistochemical staining and quantitative reverse transcriptase polymerase chain reaction (qRT-PCR) demonstrated that the scaffolds supported growth and differentiation of hESCs. Expression levels of neural crest related genes (AP2a, FoxD3, HNK1, P75, Sox1, Sox10) and osteoblast-related genes (Runx2, SPP1 and BGLA) on the scaffolds in osteogenic medium were significantly higher than on the scaffolds in growth and cell culture plates in osteogenic medium, respectively (p<0.05). Polymerase chain reaction array experiments demonstrated increased expression of ECM and adhesion molecule-related genes on the scaffolds. In conclusion, osteoconductive scaffolds such as ß-TCP scaffolds promoted differentiation of hESCs, particularly expression of genes related to neural crest stem cell and osteoblastic differentiations. Beta-TCP scaffolds could be an alternative cell culture substrate for neural crest and osteogenic differentiation of hESCs. Optimization of culture medium may be necessary to enhance lineage restriction of hESCs on the ß-TCP scaffolds.

ESR investigations of gamma irradiated medical devices

Guided tissue regeneration (GTR) and guided bone regeneration (GBR) biomaterials have been employed in recent years for periodontal procedures. In the present study, widely used dental GTR/GBR biomaterials (grafts: G1, G2, G3 and membranes: M1, M2, M3, M4) were exposed to gamma irradiation at an absorbed dose range of 0–50kGy and the radiolytic intermediates that have been created in the samples upon irradiation were characterized in detail by Electron Spin Resonance (ESR) spectroscopy. We aimed to standardize the measurement conditions for practical applications of gamma radiation sterilization of GTR/GBR biomaterials. We investigated the characteristic features of free radicals in gamma irradiated GTR/GBR biomaterials and examined the stability of the induced radicals at room temperature and accelerated stability conditions with ESR spectroscopy including dose-response curves, microwave power studies, dosimetric features of the biomaterials, variations of the peak heights with temperature, and long term stabilities of the radical species. Long-term stability studies have shown that G1 is quite stable even in accelerated storage conditions. The signal intensities of graft-type GTR/GBR biomaterials stored in normal and stability conditions have decreased very rapidly even only a few days after gamma irradiation sterilization. Thus, those samples indicating relatively low stability features can be very good candidates for the radiosterilization process. The beta-tricalcium phosphate and PLGA containing G1 and M1 respectively have found to be the most gamma stable bone substitute biomaterials and be safely sterilized by gamma radiation. ESR spectroscopy is an appropriate technique in giving important detailed spectroscopic findings in the gamma radiation sterilization studies of GTR/GBR biomaterials.

Risk factors for failure of revision total hip arthroplasty using a Kerboull-type acetabular reinforcement device

BackgroundThe present study aimed to identify the risk factors associated with revision total hip arthroplasty (THA) failure using a Kerboull-type (KT) plate.MethodsWe analyzed 77 revision THAs using cemented acetabular components with a KT plate for aseptic loosening between May 2000 and March 2012. We examined the association of bone graft type, acetabular bone defects, age at the time of surgery, preoperative Japanese Orthopaedic Association (JOA) score, postoperative JOA hip score, and body mass index, with radiographic failure as the outcome.ResultsThe 7.4-year radiographic failure survival rate was 81.6%. The survival rate was significantly different between the beta-tricalcium phosphate (β-TCP) group and the bulk allograft group (p = 0.019). The survival curves were also significantly different between the β-TCP group and bulk allograft group (p = 0.036). American Academy of Orthopaedic Surgeons type IV was significantly associated with radiographic failure (odds ratio [OR]: 15.5, 95% confidence interval [CI]: 1.4–175.4; p = 0.032).ConclusionsThe midterm outcomes of revision THA indicate that type of bone graft and bone defect size may affect radiographic survival rate when using a KT plate.

Behavior of macrophage and osteoblast cell lines in contact with the β-TCP biomaterial (beta-tricalcium phosphate)

Beta-tricalcium phosphate (β-TCP) is a synthetic ceramic used for filling bone defects. It is a good alternative to autologous grafts since it is biocompatible, resorbable and osteoconductive. Previous in vivo studies have shown that macrophages are one of the first cells coming in contact with the biomaterial followed by osteoclasts and osteoblasts that will elaborate new bone packets. Studies have focused on osteoclast morphology and very few of them have investigated the role of macrophages. The aims of this study were to characterize (i) the biomaterial surface; (ii) the in vitro behavior of macrophages (J774.2 and Raw264.7 cells) using the description of cell morphology by scanning electron microscopy (SEM) at 7 and 14 days; (iii) the behavior of osteoblasts (SaOs-2 and MC3T3-E1 cells) seeded at the surface of the biomaterial 24, 48 and 72hours by SEM and confocal microscopy. Cell proliferation was analyzed by MTT assays. Viability and affinity of the macrophages for β-TCP were found significantly increased after 7 and 14d. MC3T3-E1 cells were anchored and stretched onto the β-TCP surface as early as 24h with a high proliferation rate (+190%) when compared to the surface of a well plate. SaOs-2 exhibited the same morphological profile at 72h. Proliferation became significantly higher compared to the plastic surface at only 72h (+129%). This study emphasises the importance of choice of the cell line used in exploring the osteoconductive and osteoinductive properties of a biomaterial. Additional studies are needed to analyze differentiation of macrophages into giant multinucleated cells and how the biomaterial surface influences osteoblast differentiation.

Effect of Calcination Temperatures on Phase Transformation and Stability of β-Tricalcium Phosphate Powder Synthesized by a Wet Precipitation Method

Beta-tricalcium phosphate (β-TCP) was never synthesized directly using an aqueous method. As-precipitated powder from a wet chemical method needs to undergo a heat-treatment process (or calcination) to enable the intermediate phase (s) to be transformed into single-phase TCP. In this work, calcium hydroxide, (Ca (OH)2), and phosphoric acid, (H3PO4), were mixed as the precursor materials with a Ca/P ratio of 1.5,. The mixture was stirred at a fixed stirring speed of 200 rpm and a stirring duration of 2 hours. The precipitate thus obtained was filtered and dried overnight before being tested by differential scanning calorimetry and thermogravimetry (DSC/TG) up to 1300°C for thermal behaviour upon firing. The powders were then calcined at various temperatures (500°C, 700°C, 900°C 1000°C, 1100°C, 1200°C and 1300°C) for a duration of 2 hours. The calcined powders obtained were analysed by x-ray diffraction (XRD) to determine the transformation of phases. Monetite and hydroxyapatite were the phases detected after calcination at 500°C and 700°C, whilst at a temperature of 900°C up to 1300°C, only a single phase β-TCP was observed. Microstructural observation by scanning electron microscopy (SEM) was conducted on the β-TCP powders obtained at calcination temperatures of 900°C to 1300°C. The results showed a massive crystal growth of the aggregated particles, but even so, the phase remained stable as monolithic β-TCP.