Engineering electrospun multicomponent polyurethane scaffolding platform comprising grapeseed oil and honey/propolis for bone tissue regeneration.

Essential oils play an important role in reducing the pain and inflammation caused by bone fracture.In this study, a scaffold was electrospun based on polyurethane (PU), grape seed oil, honey and propolis for bone tissue-engineering applications. The fiber diameter of the electrospun PU/grape seed oil scaffold and PU/grape seed oil/honey/propolis scaffold were observed to be reduced compared to the pristine PU control. FTIR analysis revealed the existence of grape seed oil, honey and propolis in PU identified by CH band peak shift and also hydrogen bond formation. The contact angle of PU/grape seed oil scaffold was found to increase owing to hydrophobic nature and the contact angle for the PU/grape seed/honey oil/propolis scaffold were decreased because of hydrophilic nature. Further, the prepared PU/grape seed oil and PU/grape seed oil/honey/propolis scaffold showed enhanced thermal stability and reduction in surface roughness than the control as revealed in thermogravimetric analysis (TGA) and atomic force microscopy (AFM) analysis. Further, the developed nanocomposite scaffold displayed delayed blood clotting time than the pristine PU in the activated prothrombin time (APTT) and partial thromboplastin time (PT) assay. The hemolytic assay and cytocompatibility studies revealed that the electrospun PU/grape seed oil and PU/grape seed oil/honey/propolis scaffold possess non-toxic behaviour to red blood cells (RBC) and human fibroblast cells (HDF) cells indicating better blood compatibility and cell viability rates. Hence, the newly developed electrospun nanofibrous composite scaffold with desirable characteristics might be used as an alternative candidate for bone tissue engineering applications.

Preparation and biocompatibility of demineralized bone matrix/sodium alginate putty.

Demineralized bone matrix (DBM) powder is widely used for bone regeneration due to its osteoinductivity and osteoconductivity. However, difficulties with handling, tendency to migrate from graft sites and lack of stability after surgery sometimes limit the clinical utility of this material. In this work, the possibility of using sodium alginate (ALG) carrier to deliver DBM powder was assessed. DBM-ALG putty with the DBM:ALG weight ratio of 5:5, 6:4, 7:3, 8:2 were prepared, respectively. The properties of the formed composite, including discrete degree, washout property, pH, equilibrium swelling as well as cytotoxicity in vivo, were adopted to ascertain the optimal ratio of DBM and ALG. The discrete diameter increased from 1.25 cm (5:5) to 2.08 cm (8:2) with the increase of DBM content. There was significant difference between the 8:2 group and the other groups in discrete diameter. The ratio of DBM had a significant effect on the swelling value. The pH of composites showed an increase trend with the DBM ratio's increase, when the ratio reached 7:3, the pH (7.22) was approximately equal to the body fluid. The proliferation of MC3T3-E1 cells was inhibited in the 5:5, 6:4 and 7:3 groups, while a slightly increased in the 8:2 group. The DBM-ALG with the optimal ratio of 7:3 was confirmed based on the results of the above mentioned. The histocompatibility of DBM-ALG (7:3) was examined using a rat model in which the materials were implanted subcutaneously, compared with the polyethylene, ALG and DBM. The study in vivo showed DBM-ALG (7:3) had a lower inflammatory response than DBM, a higher vascularization than ALG. The osteoinduction of DBM-ALG (7:3) was evaluated by co-culturing with MC3T3-E1 in vitro, compared with the DMEM, ALG and DBM. The results indicated calcification area in the DBM-ALG group was similar to that in the DBM group, larger than ALG group and DMEM group. The DBM-ALG (7:3) putty is promising as a directly injectable graft for repair of bone defect.

Evaluation of the osteoconductive potential of poly(propylene carbonate)/nano-hydroxyapatite composites mimicking the osteogenic niche for bone augmentation.

Nano-hydroxyapatite (n-HA) reinforced poly(propylene carbonate) (PPC) composites were prepared for bone repair and reconstruction. The effects of reinforcement on the morphology, mechanical properties and biological performance of n-HA/PPC composites were investigated. The surface morphology and mechanical properties of the composites were characterized by scanning electron microscopy (SEM) and universal material testing machine. The analytical data showed that good incorporation and dispersion of n-HA crystals could be obtained in the PPC matrix at a 30:70 weight ratio. With the increase of n-HA content, the tensile strength increased and the fracture elongation rate decreased. In vitro cell culture revealed that the composite was favorable template for cell attachment and growth. In vivo implantation in femoral condyle defects of rabbits confirmed that the n-HA/PPC composite had good biocompatibility and gradual biodegradability, exhibiting good performance in guided bone regeneration. The results demonstrates that the incorporation of n-HA crystals into PPC matrix provides a practical way to produce biodegradable and cost-competitive composites mimicking the osteogenic niche for bone augmentation.

Cytotoxicity Evaluation and Crystallochemical Analysis of a Novel and Commercially Available Bone Substitute Material.

BACKGROUND: Alloplastic biomaterials are an alternative for autologous transplants and xenografts in oral surgery and dental implantology. These non-immunogenic and resorbable materials are becoming the basis for complete and predictable guided bone regeneration in many cases. The chemical composition of a great majority of them is based on calcium phosphate salts. In vivo performance is often variable. OBJECTIVES: The objective was to evaluate the biological and chemical properties of an experimental bone substitute material. MATERIAL AND METHODS: The present research focuses on the cytotoxicity comparison and physiochemical characterization of two biomaterials: a novel chitosan/tricalcium phosphate/alginate composite (CH/TCP/Ag) and a commercially available synthetic bone graft made of HA (60%) and ßTCP (40%) (HA/TCP). The materials were evaluated according to PN-EN ISO 10993 Biological evaluation of medical devices i.e. cytotoxicity on mouse fibroblasts (L929) and, in addition, tests on human osteoblasts (hFOB1.19) and human osteosarcoma (MG-63) were conducted. The crystallochemical analysis was performed using the X-ray powder diffraction method. The Bruker-AXS D8 Advance diffractometer (Karlsruhe, Germany) was used to collect diffractograms. RESULTS: The tested materials showed a close resemblance in chemical composition and a considerable differentiation in cytotoxic response. CONCLUSIONS: The novel composite demonstrated a high degree of cytocompatibility, which is promising in future clinical trials.

Hydroxyapatite-based materials of marine origin: a bioactivity and sintering study.

Single phase hydroxyapatite (HAp) and biphasic material hydroxyapatite/ß-tricalcium phosphate (HAp/ß-TCP) were obtained from a marine source (Atlantic cod fish bones). Here we report a study on the biological properties of these materials, including cytotoxicity, bioactivity and haemocompatibility. Results showed that the materials are not cytotoxic, neither in their powder nor in pellet form; indeed growth of Saos-2 cells was comparable to that of commercial. The haemolysis rate was lower than 2%; hence the materials can be classified as non-haemolytic. Moreover, when immersed in Simulated Body Fluid (SBF), crystal formation was observed on the surface of both materials. The sintering behaviour of the samples was also studied; both powders showed very high sinterability (density higher than 95% of the theoretical value). Overall, these results confirm the suitability of these materials for biomedical applications.

Graded porous polyurethane foam: a potential scaffold for oro-maxillary bone regeneration.

Bone tissue engineering applications demand for biomaterials offering a substrate for cell adhesion, migration, and proliferation, while inferring suitable mechanical properties to the construct. In the present study, polyurethane (PU) foams were synthesized to develop a graded porous material-characterized by a dense shell and a porous core-for the treatment of oro-maxillary bone defects. Foam was synthesized via a one-pot reaction starting from a polyisocyanate and a biocompatible polyester diol, using water as a foaming agent. Different foaming conditions were examined, with the aim of creating a dense/porous functional graded material that would perform at the same time as an osteoconductive scaffold for bone defect regeneration and as a membrane-barrier to gingival tissue ingrowth. The obtained PU was characterized in terms of morphological and mechanical properties. Biocompatibility assessment was performed in combination with bone-marrow-derived human mesenchymal stromal cells (hBMSCs). Our findings confirm that the material is potentially suitable for guided bone regeneration applications.

Genotoxicity effect, antioxidant and biomechanical correlation: experimental study of agarose-chitosan bone graft substitute in New Zealand white rabbit model.

Bone loss associated with skeletal trauma or metabolic diseases often requires bone grafting. In such situations, a biomaterial is necessary for migrated cells to produce new tissue. In this study, agarose-chitosan was implanted in the femoral condyle of New Zealand White rabbits that were divided into three groups: Group I was used as control; Groups II and III were used as implanted tissue with agarose-chitosan and presenting empty defects, respectively. This study evaluated the agarose-chitosan biocompatibility by determining the in vivo genotoxicity, oxidative stress balance that correlated with the hardness mechanical property. Moreover, the histopathological and quantitative elements analyzed by using inductively coupled plasma optical emission spectrometry were determined. After 30 days of implantation, the in vivo analysis of genotoxicity showed that agarose-chitosan did not induce chromosome aberration or micronucleus damage. A significant decrease in thiobarbituric and acid-reactive substance was observed after agarose-chitosan implantation in the bone tissue. Superoxide dismutase, catalase and glutathione peroxidase were significantly enhanced in agarose-chitosan-treated group compared with that of control group. A negative correlation coefficient of the mechanical property with malonyldialdehyde level was detected (R = -0.998). The histological study exhibited a significantly increased angiogenesis and newly formed tissue. No presence of inflammatory process, necrotic or fibrous tissue was detected. Major and trace elements such as Ca, P, Zn, Mg and Fe were increased significantly in the newly formed bone. These findings show that agarose-chitosan biomaterial implantation might be effective for treating trauma and bone regeneration.

Octacalcium phosphate ceramics combined with gingiva-derived stromal cells for engineered functional bone grafts.

Biocompatible ceramic fillers are capable of sustaining bone formation in the proper environment. The major drawback of these scaffolding materials is the absence of osteoinductivity. To overcome this limitation, bioengineered scaffolds combine osteoconductive components (biomaterials) with osteogenic features such as cells and growth factors. The bone marrow mesenchymal stromal cells (BMMSCs) and the ß-tricalcium phosphate (ß-TCP) are well-known and characterized in this regard. The present study was conducted to compare the properties of novel octacalcium phosphate ceramic (OCP) granules with ß-TCP (Cerasorb(®)), gingiva-derived mesenchymal stromal cells (GMSCs) properties with the BMMSCs and osteogenic and angiogenic properties of a bioengineered composite based on OCP granules and the GMSCs. This study demonstrates that GMSCs and BMMSСs have a similar osteogenic capacity. The usage of OCP ceramic granules in combination with BMMSCs/GMSCs significantly affects the osteo- and angiogenesis in bone grafts of ectopic models.

Pre-clinical evaluation of a new coral-based bone scaffold.

Coral is used worldwide for bone reconstruction. The favorable characteristics that make this material desirable for implantation are (i) osteoinduction, (ii) and osteoconduction. These proprieties have been demonstrated by in vivo studies with animal models and clinical trials over a twenty-year period. Also poly(2-hydroxyethylmethacrylate) [poly(HEMA)] is a widely used biomaterial. By using coral and poly(HEMA), a scaffold for bone reconstruction application has been recently synthesized. Cytological, histological and genetic analyses were performed to characterize this new alloplastic material. Four samples were analyzed: (a) white coral (WC), (b) red coral (RC), (c) WC plus polymer (WCP) and (d) RC plus polymer (RCP). Quantification of mitochondrial dehydrogenase activity by MTT assay was performed as indirect detector of cytotoxicity. In vivo effects were revealed by implanting corals and coral-based polymers in rabbit tibia. Samples were collected after 4 weeks and subjected to histological analysis. To evaluate the genetic response of cells to corals and coral-derived polymers an osteoblastlike cell line (i.e. MG63) was cultured in wells containing (a) medium, (b) medium plus corals and (c) medium plus two types of scaffolds (RCP or WCP). RNAs extracted from cells were retro-transcribed and hybridized on DNA 19.2K microarrays. No cytotoxicity was detected in corals and coral-based biopolymers. No inflammation or adverse effect was revealed by histological examination. By microarray analysis 154 clones were differentially expressed between RC and WC (81 up and 73 down regulated) whereas only 15 clones were repressed by the polymer. Histological evaluation not only confirmed that coral is a biocompatible material, but also that the polymer has no adverse effect. Microarray results were in agreement with cytological and histological analyses and provided further data regarding the genetic effects of RC, WC and the new polymer.

Scleractinium coral aquaculture skeleton: a possible 3D scaffold for cell cultures and bone tissue engineering.

Cytocompatibility of 5 coral aquaculture skeleton species derived from two families (Acroporidae and Pocilloporidae) was studied over the course of in vitro culturing in continuous human fibroblast culture by the MMT test. Biocompatibility and capacity of scaffold to "transfer" cell cultures (specifically, multipotent mesenchymal stromal cells) to sites of implantation were studied in vivo by subcutaneous implantation of skeletal fragments to rats. All coral skeleton aquaculture specimens were cytocompatible (nontoxic and with surface matrix characteristics satisfactory for cells), biocompatible, and could be tried as 3D matrices for bone tissue engineering.

Synthesis and cytotoxicity evaluation of granular magnesium substituted beta-tricalcium phosphate

Objective: The aim of this study was to produce dense granules of tricalcium phosphate (β-TCP) and magnesium (Mg) substituted β-TCP, also known as β-TCMP (Mg/Ca=0.15 mol), in order to evaluate the impact of Mg incorporation on the physicochemical parameters and in vitro biocompatibility of this novel material. Material and Methods: The materials were characterized using X-ray diffraction (XRD), infrared spectroscopy (FTIR), electron microscopy and inductively coupled plasma (ICP). Biocompatibility was assayed according to ISO 10993-12:2007 and 7405:2008, by two different tests of cell survival and integrity (XTT and CVDE). Results: The XRD profile presented the main peaks of β-TCP (JCPDS 090169) and β-TCMP (JCPDS 130404). The characteristic absorption bands of TCP were also identified by FTIR. The ICP results of β-TCMP granules extract showed a precipitation of calcium and release of Mg into the culture medium. Regarding the cytotoxicity assays, β-TCMP dense granules did not significantly affect the mitochondrial activity and relative cell density in relation to β-TCP dense granules, despite the release of Mg from granules into the cell culture medium. Conclusion: β-TCMP granules were successfully produced and were able to release Mg into media without cytotoxicity, indicating the suitability of this promising material for further biological studies on its adequacy for bone therapy.

Evaluation of hydroxyapatite-bioglass and hydroxyapatite-ethyl vinyl acetate composite extracts on antioxidant defense mechanism and genotoxicity: an in vitro study.

Hydroxyapatite-bioglass (HA BG) and hydroxyapatite-ethyl vinyl acetate (HA EVA) are two composite materials that have been developed for bone substitution. Their activity on antioxidant defense mechanism and genotoxicity has not been investigated before. To further confirm its biocompatibility, the present study was undertaken to investigate the effect of HA BG and HA EVA on mice liver antioxidant mechanism along with chromosomal aberrations in human lymphocytes. Physiological saline extract of HA BG and HA EVA showed no adverse effect on liver antioxidant mechanism compared to the cyclophosphamide (CP)-induced toxicity on mice liver homogenate. The results were judged from the in vitro studies made on reduced glutathione, glutathione reductase and lipid peroxidation. These results were well supported by CP- and mytomycin C (MC)-induced genotoxicity studies on human lymphocytes in the presence and absence of a metabolic activator (S9). Hence, it was suggested that these tests could be considered for preliminary toxicological screening of materials intended for clinical applications ahead of in vivo animal model evaluation.

Zirconia-hydroxyapatite composite material with micro porous structure.

OBJECTIVES: Titanium plates and apatite blocks are commonly used for restoring large osseous defects in dental and orthopedic surgery. However, several cases of allergies against titanium have been recently reported. Also, sintered apatite block does not possess sufficient mechanical strength. In this study, we attempted to fabricate a composite material that has mechanical properties similar to biocortical bone and high bioaffinity by compounding hydroxyapatite (HAp) with the base material zirconia (ZrO(2)), which possesses high mechanical properties and low toxicity toward living organisms. METHODS: After mixing the raw material powders at several different ZrO(2)/HAp mixing ratios, the material was compressed in a metal mold (8 mm in diameter) at 5 MPa. Subsequently, it was sintered for 5 h at 1500°C to obtain the ZrO(2)/HAp composite. The mechanical property and biocompatibility of materials were investigated. Furthermore, osteoconductivity of materials was investigated by animal studies. RESULTS: A composite material with a minute porous structure was successfully created using ZrO(2)/HAp powders, having different particle sizes, as the starting material. The material also showed high protein adsorption and a favorable cellular affinity. When the mixing ratio was ZrO(2)/HAp=70/30, the strength was equal to cortical bone. Furthermore, in vivo experiments confirmed its high osteoconductivity. SIGNIFICANCE: The composite material had strength similar to biocortical bones with high cell and tissue affinities by compounding ZrO(2) and HAp. The ZrO(2)/HAp composite material having micro porous structure would be a promising bone restorative material.

In vitro biomechanical and biocompatible evaluation of natural hydroxyapatite/chitosan composite for bone repair.

PURPOSE: To evaluate the biomechanical properties and biocompatibility of natural hydroxyapatite/chitosan (HA/CS) composites. METHODS: The natural HA/CS composites with a different proportion of HA and CS were prepared by the cross-linking method, and then the compressive strength, microstructure and pH values of extracts from these composites were measured by SEM and pH meter, respectively. Subsequently, the biocompatibility of the composites was evaluated by means of a series of biological tests, including MTT, acute systemic toxicity, heat source, and hemolysis tests in vitro. RESULTS: The chitosan content in the composites had significantly influenced the mechanical properties and microstructure of the composites. The pH value of the composite extract was approximately 7.0, which was very close to that of human plasma. Furthermore, the natural HA/CS composites showed no cytotoxicity, irritation, teratogenicity, carcinogenicity and special pyrogen. CONCLUSIONS: These results indicated that the natural HA/CS composite may be a potential bone repair material.

N-acetyl cysteine alleviates cytotoxicity of bone substitute.

Lack of cytocompatibility in bone substitutes impairs healing in surrounding bone. Adverse biological events around biomaterials may be associated with oxidative stress. We hypothesized that a clinically used inorganic bone substitute is cytotoxic to osteoblasts due to oxidative stress and that N-acetyl cysteine (NAC), an antioxidant amino acid derivative, would detoxify such material. Only 20% of rat calvaria osteoblasts were viable when cultured on commercial deproteinized bovine bone particles for 24 hr, whereas this percentage doubled on bone substitute containing NAC. Intracellular ROS levels markedly increased on and under bone substitutes, which were reduced by prior addition of NAC to materials. NAC restored suppressed alkaline phosphatase activity in the bone substitute. Proinflammatory cytokine levels from human osteoblasts on the bone substitute decreased by one-third or more with addition of NAC. NAC alleviated cytotoxicity of the bone substitute to osteoblastic viability and function, implying enhanced bone regeneration around NAC-treated inorganic biomaterials.

Systemic and local reactions of a water-soluble copolymer bone on a bony defect of rabbit model.

BACKGROUND: Ostene, a synthetic water-soluble bone hemostatic agent, is commercially available. In the current study, we evaluated the systemic and local effects of this copolymer in a rabbit model. METHODS: Eighteen rabbits underwent creation of a bony defect at right iliac crest. These rabbits were then evenly divided into 3 groups. In group 1, the defect surfaces were treated with bone wax; in group 2, the defect surfaces were treated with Ostene; in group 3, the defect surfaces were not treated with anything. Then, the animals underwent blood examinations, including WBC count, CRP, and ESR at 0, 1, 3, and 6 weeks, and were killed at 6 weeks for histologic examination. Another 6 rabbits (group 4) underwent the same surgical treatment of group 2 animals but had blood examinations of BUN and creatinine. RESULTS: The blood examinations showed that the WBC count, CRP, and ESR of all the animals in the first 3 groups were within normal limits in the postoperative periods. Microscopic examinations demonstrated residual bone wax and fibrotic tissue at the defect surfaces in group 1 animals. However, there was no Ostene at the defect surfaces in group 2 animals. The groups 2 and 3 animals showed no fibrotic tissue at the defect surfaces. The group 4 animals showed normal serum levels of BUN and creatinine in the postoperative periods. CONCLUSION: Ostene is absorbable and induces no systemic inflammation (including acute renal damage) and local inflammation in animal bodies.

In vitro cytotoxicity of a novel injectable and biodegradable alveolar bone substitute.

The unsaturated polyphosphoester (UPPE) polymer is being investigated as an injectable and biodegradable system for alveolar bone repair in the treatment of periodontal diseases. The incorporation of beta-tricalcium phosphate (beta-TCP) particles into the UPPE polymer was previously shown to significantly increase the material's mechanical properties. Moreover, in vitro experiments demonstrated that the UPPE/beta-TCP composite was capable of zero-order release of tetracycline for over 2 weeks. In this study, we investigated the in vitro cytotoxicity of each individual component, the resulting cross-linked network and the degradation products of the UPPE/beta-TCP composite using an AlamarBlue viability assay. We confirmed that each individual component except beta-TCP and the in vitro degradation products of the composite displayed a dose-dependent cytotoxic response. Once cross-linked, however, the composite did not demonstrate an adverse response. Our results suggest that the UPPE/beta-TCP composite holds great promise for use as an injectable and biodegradable alveolar bone substitute.

Surface- and nonsurface-dependent in vitro effects of bone substitutes on cell viability.

The aim of the present in vitro study was to evaluate the influence of different bone substitute materials (BSM) on the viability of human primary osteoblasts (PO), bone marrow mesenchymal cells (BMMC), and nonadherent myelomonocytic cells (U937). Six different bone substitute materials were tested: Bio-Oss Spongiosa (BOS), Tutodent Chips (TC), PepGen P-15 (P-15), Ostim (OM), BioBase (BB), and Cerasorb (CER). Cells were cultivated on comparable volumes of BSM in 96-well plates. Cell culture-treated polystyrol (Nunclon Delta surface; C) served as positive control. After 2 h and 3, 6, 10, and 14 days, viability of cells was evaluated using a standardized ATP viability assay (CellTiter Glo). Nonsurface-dependent effects of the materials were separately tested using nonadherent U937 suspension cells. For statistical analysis, the Mann-Whitney test was used. Results were considered statistically significant at P < 0.05. Cell viability of PO increased significantly on TC, C, and CER followed by BB. No changes were found for P-15 and decreasing viability for BOS and OM. BMMC showed similar results on C, TC, CER, and P-15. Lower viability for BB and no viability could be detected for BOS and OM (Mann-Whitney test, respectively). Nonadherent cells displayed increasing viability in presence of CER, BB, and BOS. No changes were observed for TC and P-15, whereas for OM, no viability was detected after a maximum cultivation period of 3 days. It was concluded that granular hydroxyapatite (HA; TC, BOS, P-15) and alpha- and beta-tricalciumphosphate (CER, BB) support, whereas nanosized HA (OM) limit or even inhibit surface- and nonsurface-related cell viability in the in vitro model used.

In vitro and in vivo evaluation of lyophilized bovine bone biocompatibility.

INTRODUCTION: The use of bone grafts in orthopedic, maxillofacial and dental surgery has been growing. Nevertheless, both fresh autografts and frozen allografts have limitations, and therefore, alternative synthetic or natural biomaterials, such as processed and lyophilized bovine bone graft have been developed. OBJECTIVE: To evaluate in vitro and in vivo biocompatibility of lyophilized bovine bone manufactured in a semi-industrial scale, according to a modifical protocol developed by the authors. METHODS: Samples of bovine cancellous bone were processed according to a protocol developed by Kakiuchi et al., and modified to process samples of bovine cancellous bone. The following trials were performed: in vitro cytotoxicity, in vivo acute systemic toxicity, in vivo oral irritation potential, in vitro pyrogenic reaction, and bioburden. RESULTS: The in vitro evaluation of lyophilized bovine cancellous bone revealed an absence of cytotoxicity in 100% of the samples. Regarding in vivo evaluation of acute systemic toxicity, neither macroscopic abnormalities nor deaths were noted in the animals. Pyrogenicity was not greater than 0.125 UE/ml in any of the samples. The bioburden revealed negative results for microbial growth before sterilization. Regarding the oral irritation potential, in vivo evaluation at 24 and 72 hours showed that the animals had no edema or erythema on the oral mucosa. CONCLUSION: The protocol changes established by the authors to prepare lyophilized bovine cancellous bone at a semi-industrial scale is reproducible and yielded a product with excellent biocompatibility.

Processed bovine dentine as a bone substitute.

OBJECTIVES: Different forms of allogenic dentine have been studied for their potential use as bone substitutes. We report a new method for processing bovine dentine that results in a sterile bioactive material for repair and regeneration of bone. METHODS: Extracted bovine dentine was processed mechanically and chemically with inorganic and organic solvents, and sterilised. The in vitro biocompatibility on human gingival fibroblasts was assessed by the Alamar Blue assay and the in vivo biocompatibility evaluated by implantation of the processed dentine into rats' femurs. RESULTS: The dentine showed excellent biocompatibility in vitro, stimulated formation of new bone and was completely incorporated into the new bone in vivo. SIGNIFICANCE: Processed bovine dentine has the potential to be used as a suitable substitute in bone repair and regeneration.