Repair Of Critical Bone Defects Research Articles

Janus silk fibroin/polycaprolactone-based scaffold with directionally aligned fibers and porous structure for bone regeneration

To promote bone repair, it is desirable to develop three-dimensional multifunctional fiber scaffolds. The densely stacked and tightly arranged conventional two-dimensional electrospun fibers hinder cell penetration into the scaffold. Most of the existing three-dimensional structural materials are isotropic and monofunctional. In this research, a Janus nanofibrous scaffold based on silk fibroin/polycaprolactone (SF/PCL) was fabricated. SF-encapsulated SeNPs demonstrated stability and resistance to aggregation. The outside layer (SF/PCL/Se) of the Janus nanofiber scaffold displayed a structured arrangement of fibers, facilitating cell growth guidance and impeding cell invasion. The inside layer (SF/PCL/HA) featured a porous structure fostering cell adhesion. The Janus fiber scaffold containing SeNPs notably suppressed S. aureus and E. coli activities, correlating with SeNPs concentration. In vitro, findings indicated considerable enhancement in alkaline phosphatase (ALP) activity of MC3T3-E1 osteoblasts and upregulation of genes linked to osteogenic differentiation with exposure to the SF/PCL/HA/Se Janus nanofibrous scaffold. Moreover, in vivo, experiments demonstrated successful critical bone defect repair in mouse skulls using the SF/PCL/HA/Se Janus nanofiber scaffold. These findings highlight the potential of the SF/PCL-based Janus nanofibrous scaffold, integrating SeNPs and nHA, as a promising biomaterial in bone tissue engineering.

Repair of a rat calvaria defect with injectable strontium (Sr)-doped polyphosphate dicalcium phosphate dehydrate (P-DCPD) ceramic bone grafts.

The trace element strontium (Sr) enhances new bone formation. However, delivering Sr, like other materials, in a sustained manner from a ceramic bone graft substitute (BGS) is difficult. We developed a novel ceramic BGS, polyphosphate dicalcium phosphate dehydrate (P-DCPD), which delivers embedded drugs in a sustained pattern. This study assessed the in vitro and in vivo performance of Sr-doped P-DCPD. In vitro P-DCPD and 10%Sr-P-DCPD were nontoxic and eluents from 10%Sr-P-DCPD significantly enhanced osteoblastic MC3T3 cell differentiation. A sustained, zero-order Sr release was observed from 10%Sr-P-DCPD for up to 70 days. When using this BGS in a rat calvaria defect model, both P-DCPD and 10% Sr-P-DCPD were found to be biocompatible and biodegradable. Histologic data from decalcified and undecalcified tissue showed that 10%Sr-P-DCPD had more extensive new bone formation compared with P-DCPD 12-weeks after surgery and the 10%Sr-P-DCPD had more organized new bone and much less fibrous tissue at the defect margins. The new bone was formed on the surface of the degraded ceramic debris within the bone defect area. P-DCPD represented a promising drug-eluting BGS for repair of critical bone defects.

Ligand-Selective Targeting of Macrophage Hydrogel Elicits Bone Immune-Stem Cell Endogenous Self-Healing Program to Promote Bone Regeneration.

Targeting macrophages can facilitate the site-specific repair of critical bone defects. Herein, a composite hydrogel, gelatin-Bletilla striata polysaccharide-mesoporous bioactive glass hydrogel (GBMgel), is constructed via the self-assembly of mesoporous bioactive glass on polysaccharide structures, through the Schiff base reaction. GBMgel can efficiently capture macrophages and drive the recruitment of seed stem cells and vascular budding required for regeneration in the early stages of bone injury, and the observed sustained release of inorganic silicon ions further enhances bone matrix deposition, mineralization, and vascular maturation. Moreover, the use of macrophage-depleted rat calvarial defect models further confirms that GBMgel, with ligand-selective macrophage targeting, increases the bone regeneration area and the proportion of mature bone. Mechanistic studies reveal that GBMgel upregulates the TLR4/NF-κB and MAPK macrophage pathways in the early stages and the JAK/STAT3 pathway in the later stages; thus initiating macrophage polarization at different time points. In conclusion, this study is based on the endogenous self-healing properties of bone macrophages, which enhances stem cell homing, and provides a research and theoretical basis upon which bone tissue can be reshaped and regenerated using the body's immune power, providing a new strategy for the treatment of critical bone defects.

Injectable phase-separated tetra-armed poly(ethylene glycol) hydrogel scaffold allows sustained release of growth factors to enhance the repair of critical bone defects

With the rising prevalence of bone-related injuries, it is crucial to improve treatments for fractures and defects. Tissue engineering offers a promising solution in the form of injectable hydrogel scaffolds that can sustain the release of growth factors like bone morphogenetic protein-2 (BMP-2) for bone repair. Recently, we discovered that tetra-PEG hydrogels (Tetra gels) undergo gel-gel phase separation (GGPS) at low polymer content, resulting in hydrophobicity and tissue affinity. In this work, we examined the potential of a newer class of gel, the oligo-tetra-PEG gel (Oligo gel), as a growth factor-releasing scaffold. We investigated the extent of GGPS occurring in the two gels and assessed their ability to sustain BMP-2 release and osteogenic potential in a mouse calvarial defect model. The Oligo gel underwent a greater degree of GGPS than the Tetra gel, exhibiting higher turbidity, hydrophobicity, and pore formation. The Oligo gel demonstrated sustained protein or growth factor release over a 21-day period from protein release kinetics and osteogenic cell differentiation studies. Finally, BMP-2-loaded Oligo gels achieved complete regeneration of critical-sized calvarial defects within 28 days, significantly outperforming Tetra gels. The easy formulation, injectability, and capacity for sustained release makes the Oligo gel a promising candidate therapeutic biomaterial.

Optimize the pore size-pore distribution-pore geometry-porosity of 3D-printed porous tantalum to obtain optimal critical bone defect repair capability

The treatment and reconstruction of large or critical size bone defects is a challenging clinical problem. Additive manufacturing breaks the technical difficulties of preparing complex conformation and anatomically matched personalized porous tantalum implants, but the ideal pore structure for 3D-printed porous tantalum in critical bone defect repair applications remains unclear. Guiding appropriate bone tissue regeneration by regulating proper pore size-pore distribution-pore geometry-porosity is a challenge for its fabrication and application. We fabricated porous tantalum (PTa) scaffolds with six different combinations of pore structures using powder bed laser melting (L-PBF) technology. In vitro biological experiments were conducted to systematically investigate the effects of pore structure characteristics on osteoblast behaviors, showing that the bionic trabecular structure with both large and small poress facilitated cell permeation, proliferation and differentiation compared to the cubic structure with uniform pore sizes. The osteogenesis of PTa with different porosity of trabecular structures was further investigated by a rabbit condyle critical bone defect model. Synthetically, T70% up-regulated the expression of osteogenesis-related genes (ALP, COLI, OCN, RUNX-2) and showed the highest bone ingrowth area and bone contact rate in vivo after 16 weeks, with the best potential for critical bone defect repair. Our results suggested that the bionic trabecular structure with a pore size distribution of 200–1200 μm, an average pore size of 700 μm, and a porosity of 70 % is the best choice for repairing critical bone defects, which is expected to guide the clinical application of clinical 3D-printed PTa scaffolds.

Long-Term Fate and Efficacy of a Biomimetic (Sr)-Apatite-Coated Carbon Patch Used for Bone Reconstruction

Critical bone defect repair remains a major medical challenge. Developing biocompatible materials with bone-healing ability is a key field of research, and calcium-deficient apatites (CDA) are appealing bioactive candidates. We previously described a method to cover activated carbon cloths (ACC) with CDA or strontium-doped CDA coatings to generate bone patches. Our previous study in rats revealed that apposition of ACC or ACC/CDA patches on cortical bone defects accelerated bone repair in the short term. This study aimed to analyze in the medium term the reconstruction of cortical bone in the presence of ACC/CDA or ACC/10Sr-CDA patches corresponding to 6 at.% of strontium substitution. It also aimed to examine the behavior of these cloths in the medium and long term, in situ and at distance. Our results at day 26 confirm the particular efficacy of strontium-doped patches on bone reconstruction, leading to new thick bone with high bone quality as quantified by Raman microspectroscopy. At 6 months the biocompatibility and complete osteointegration of these carbon cloths and the absence of micrometric carbon debris, either out of the implantation site or within peripheral organs, was confirmed. These results demonstrate that these composite carbon patches are promising biomaterials to accelerate bone reconstruction.

3D-printed strontium-doped BG-CaSiO3-HA composite scaffolds promote critical bone defect repair by improving mechanical strength and increasing osteogenic activity

The release of silicon and calcium elements contained in silicon-based materials promotes the formation of bone. For bioactive glass prepared by the sol-gel method, water-soluble binders are usually added when preparing 3D printed scaffolds. However, the obtained scaffolds are prone to collapse when exposed to water and have low strength. At the same time, the binder needs to be removed for clinical applications, so the 3D printed scaffolds need to be sintered. Under high temperature, bioactive glass scaffolds will be transformed into composite scaffolds composed of bioglass, CaSiO3 and hydroxyapatite, while different sintering temperatures will form different crystal types of CaSiO3. In this study, SrBG-βCS-HA and BG-βCS-HA were obtained at a heating rate of 5 °C/min to 1100 °C and at the same rate to room temperature. SrBG-αCS-HA and BG-αCS-HA were obtained at a heating rate of 2 °C/min to 1200 °C and at the same rate to room temperature. In vitro and in vivo experiments verified that the presence of strontium in the obtained scaffolds after sintering further enhanced the osteogenic properties of the scaffolds. SrBG-αCaSiO3-HA and SrBG-βCaSiO3-HA were found to have relatively better osteogenic properties. The results show that SrBG-CaSiO3-HA 3D printing scaffolds have excellent clinical application potential.

Injectable, Hierarchically Degraded Bioactive Scaffold for Bone Regeneration.

Bioactive materials play vital roles in the repair of critical bone defects. However, bone tissue engineering and regenerative medicine are still challenged by the need to repair bone defects evenly and completely. In this study, we functionally simulated the natural creeping substitution process of autologous bone repair by constructing an injectable, hierarchically degradable bioactive scaffold with a composite hydrogel, decalcified bone matrix (DBM) particles, and bone morphogenetic protein 2. This composite scaffold exhibited superior mechanical properties. The scaffold promoted cell proliferation and osteogenic differentiation through multiple signaling pathways. The hierarchical degradation rates of the crosslinked hydrogel and DBM particles accelerated tissue ingrowth and bone formation with a naturally woven bone-like structure in vivo. In the rat calvarial critical defect repair model, the composite scaffold provided even and complete repair of the entire defect area while also integrating the new and host bone effectively. Our results indicate that this injectable, hierarchically degradable bioactive scaffold promotes bone regeneration and provides a promising strategy for evenly and completely repairing the bone defects.

A PLA-tPU based magnesium ion incorporated CSH/nHA bioactive porous composite scaffold for critical bone defect repair

This study use freeze-drying technology prepared a PT-M-CN bioactive porous composite scaffold for bone defects repairing. Results showed it has a great potential to promote osteogenic differentiation and new bone regeneration.

A silk fibroin/chitosan/nanohydroxyapatite biomimetic bone scaffold combined with autologous concentrated growth factor promotes the proliferation and osteogenic differentiation of BMSCs and repair of critical bone defects.

PurposeWith the goal of increasing the translational efficiency of bone tissue engineering for practical clinical applications, biomimetic composite scaffolds combined with autologous endogenous growth factors for repairing bone defects have become a current research hotspot. In this study, we prepared a silk fibroin/chitosan/nanohydroxyapatite (SF/CS/nHA) composite biomimetic scaffold and then combined it with autologous concentrated growth factor (CGF) to explore the effect of this combination on the proliferation and osteogenic differentiation of bone marrow mesenchymal stem cells (BMSCs) and the efficiency of repairing critical radial defects.MethodsThree kinds of SF/CS/nHA composite biomimetic scaffolds with mass fractions of 3%, 4%, and 5% were prepared by vacuum freeze-drying and chemical cross-linking methods, and the characteristics of the scaffolds were evaluated. In vitro, BMSCs were seeded on SF/CS/nHA scaffolds, and then CGF was added. The morphology and proliferation of BMSCs were evaluated by live-dead staining, phalloidin staining, and CCK-8 assays. ALP staining, alizarin red staining, cellular immunofluorescence, RT–PCR, and Western blotting were used to detect the osteogenic differentiation of BMSCs. In vivo, a rabbit radius critical bone defect model was constructed, and the SF/CS/nHA-BMSC scaffold cell complex combined with CGF was implanted. The effect on bone defect repair was evaluated by 3D CT scanning, HE staining, Masson staining, and immunohistochemistry.ResultsThe characteristics of 4% SF/CS/nHA were the most suitable for repairing bone defects. In vitro, the SF/CS/nHA combined CGF group showed better adhesion, cell morphology, proliferation, and osteogenic differentiation of BMSCs than the other groups (P < 0.05 for all). In vivo imaging examination and histological analysis demonstrated that the SF/CS/nHA scaffold combined with CGF had better efficiency in bone defect repair than the other scaffolds (P < 0.05 for all).ConclusionsA SF/CS/nHA composite biomimetic bone scaffold combined with autologous CGF promoted the proliferation and osteogenic differentiation of BMSCs in vitro and improved the repair efficiency of critical bone defects in vivo. This combination may have the potential for clinical translation due to its excellent biocompatibility.

Mesenchymal Stem Cell-Derived Extracellular Vesicles for Bone Defect Repair.

The repair of critical bone defects is a hotspot of orthopedic research. With the development of bone tissue engineering (BTE), there is increasing evidence showing that the combined application of extracellular vesicles (EVs) derived from mesenchymal stem cells (MSCs) (MSC-EVs), especially exosomes, with hydrogels, scaffolds, and other bioactive materials has made great progress, exhibiting a good potential for bone regeneration. Recent studies have found that miRNAs, proteins, and other cargo loaded in EVs are key factors in promoting osteogenesis and angiogenesis. In BTE, the expression profile of the intrinsic cargo of EVs can be changed by modifying the gene expression of MSCs to obtain EVs with enhanced osteogenic activity and ultimately enhance the osteoinductive ability of bone graft materials. However, the current research on MSC-EVs for repairing bone defects is still in its infancy, and the underlying mechanism remains unclear. Therefore, in this review, the effect of bioactive materials such as hydrogels and scaffolds combined with MSC-EVs in repairing bone defects is summarized, and the mechanism of MSC-EVs promoting bone defect repair by delivering active molecules such as internal miRNAs is further elucidated, which provides a theoretical basis and reference for the clinical application of MSC-EVs in repairing bone defects.

Microscopic analysis of the repair of critical bone defects in rabbits calvaria after the use of particulated autogenous bone or particulate autogenous bone associated with inorganic biomaterial

The aim of this study was to evaluate, through microscopic analysis, the repair of critical defects in rabbit calvaria after the use of particulate autogenous bone or particulate autogenous bone associated with inorganic biomaterial. Six male albino rabbits, New Zealand, were used, in which 4 defects were performed in each calvaria and randomly divided into 4 equitable groups: Group I – performed bone defect; Group II – performed bone defect and filled with particulate autogenous bone; Group III – performed bone defect and filled with particulate inorganic material (Bio-Oss®, Geistlich from Brazil); Group IV – performed bone defect and filled with particulate autogenous bone associated with particulate inorganic material (Bio-Oss® - Geistlich from Brazil) with proportion being 20:80. The analyze time of the procedure was 60 days. The microscopic analyze allowed to conclude that the autogenous, the Bio-Oss® and the Bio-Oss® associated with autogenous bone groups showed a bone neoformation on the defects, characterizing the material osteoconductive. However, the complete defect closure occurred on the autogenous bone and the autogenous bone associated with the inorganic bone, showing that the presence of the autogenous bone improves the characteristics of the biomaterial. The use of inorganic bone associated with the autogenous bone allowed a complete bone neoformation of the critic defect in the calvaria of rabbits.

Mechanically enhanced composite hydrogel scaffold for in situ bone repairs

High-efficiency repair of critical bone defects is a pressing problem in clinical practice. However, most biological replacement materials do not simultaneously satisfy the dual requirements of mechanical strength and cell compatibility. In this study, chitosan methacryloyl (CSMA) and β-tricalcium phosphate (β-TCP) were subjected to photo-crosslinking to form the CSMA/β-TCP composite hydrogel, which has strong mechanical properties contributing to bone regeneration. In addition, its scaffold can alter the morphology of bone marrow mesenchymal stem cells (BMSCs), promote their proliferation, enhance the expression of alkaline phosphatase (ALP), and augment the nodular deposition of calcium. Meanwhile, the expressions of osteogenic proteins (ALP, osteocalcin, and osteopontin) were upregulated and the regulatory mechanism of the Hippo signaling pathway was verified. Moreover, animal experiments have confirmed that CSMA/β-TCP has adequate biocompatibility and bone regeneration. These results demonstrate the immense potential of the CSMA/β-TCP composite hydrogel in bone regeneration therapy.

Biophysical Stimuli as the Fourth Pillar of Bone Tissue Engineering.

The repair of critical bone defects remains challenging worldwide. Three canonical pillars (biomaterial scaffolds, bioactive molecules, and stem cells) of bone tissue engineering have been widely used for bone regeneration in separate or combined strategies, but the delivery of bioactive molecules has several obvious drawbacks. Biophysical stimuli have great potential to become the fourth pillar of bone tissue engineering, which can be categorized into three groups depending on their physical properties: internal structural stimuli, external mechanical stimuli, and electromagnetic stimuli. In this review, distinctive biophysical stimuli coupled with their osteoinductive windows or parameters are initially presented to induce the osteogenesis of mesenchymal stem cells (MSCs). Then, osteoinductive mechanisms of biophysical transduction (a combination of mechanotransduction and electrocoupling) are reviewed to direct the osteogenic differentiation of MSCs. These mechanisms include biophysical sensing, transmission, and regulation. Furthermore, distinctive application strategies of biophysical stimuli are presented for bone tissue engineering, including predesigned biomaterials, tissue-engineered bone grafts, and postoperative biophysical stimuli loading strategies. Finally, ongoing challenges and future perspectives are discussed.

The Effect of Photobiomodulation Therapy in Different Doses on Bone Repair of Critical Size Defects in Rats: A Histomorphometric Study.

Introduction: Photobiomodulation therapy (PBM) appears to induce osteogenesis and stimulate fracture repair; because of its capacity, it is considered a promising treatment, but the characteristics of response to different radiation doses must be investigated through in vivo studies to establish their safety and effectiveness. Thus, this paper aims to analyze the effects of the PBM at different doses on the repair of critical bone defects through histological and histomorphometric analyses. Methods: Sixty 90-day-old adult rats (Rattus norvegicus, albinus, Wistar) weighing approximately 300 g were used. Critical bone defects of 5 mm in diameter were performed in their calvaria. The animals were randomly separated into 5 groups: C-Blood clot, L15-PBM 15J/cm2, L30-PBM 30 J/ cm2, L45-PBM 45 J/cm2, L60-PBM 60 J/cm2. Each group was subdivided according to observation periods of 30 and 60 days with 6 rats in each subgroup. Low-level gallium aluminum arsenide (GaAlAs) lasers were used at a 660 nm wavelength, 30 mW and 0.04 cm2 in area. The PBM was applied over 5 points; 4 points of application were distributed on the edges while one point of application was located in the center of the bone defect. PBM occurred right after the procedure. In 30 and 60 days, the animals were euthanized by anesthesia overdose and the analyses were performed. The data were analyzed statistically by the ANOVA, together with the Tukey test, whose significance level was 5%. Results: As regards the treatment factor, the highest percentage of bone neoformation was achieved by group L45-60. The group with the highest closure, despite not having a statistically significant difference with the other doses, was 45 J with only 0.49 mm between edges. Conclusion: Thus, the present study allowed concluding that the highest percentage of bone neoformation area was achieved at 45 J/cm2 in 60 days; that is, it was significantly effective in comparison with other doses.

Evaluation of Guided Bone Regeneration in Critical Defects Using Bovine and Porcine Collagen Membranes: Histomorphometric and Immunohistochemical Analyses

Guided bone regeneration (GBR) is a technique used to facilitate bone regeneration, which uses a biocompatible membrane acting as a physical barrier to prevent the adjacent connective tissue from invading the bone defect. The aim of this study was to evaluate and compare the effectiveness of bovine and porcine collagenous membranes as barriers to connective tissue invasion during the repair of critical bone defects in rat calvaria, using histological, histometric, and immunohistochemical analyses. For this study, 72 rats were divided into three groups: clot group (CG), bovine collagen group (BCG), and porcine collagen group (PCG). Analyses were performed on days 7, 15, 30, and 60. The histological results showed that the PCG exhibited bone neoformation starting from day 7, and after 30 days of repair, the surgical defect was completely filled in some animals. For the BCG, there was little bone neoformation activity in the initial periods, and from day 30 onwards, there was an increase in bone neoformation, with a greater increase on day 60. The data obtained in the histometric analysis reveal that, on day 30, the neoformed bone area did not vary greatly between the PCG and the BCG, though both varied from the CG. By day 60, the PCG presented a greater area of neoformation than the BCG. These results were corroborated by the immunohistochemistry results. In view of the results obtained, it can be concluded that all membranes studied in this research promoted GBR.

Polycaprolactone/Beta-Tricalcium Phosphate Scaffolds Obtained via Rotary Jet-Spinning: in vitro and in vivo Evaluation

This study aimed to evaluate in vitro and in vivo polymeric membranes obtained by a rotary jet-spinning process for the repair of critical bone defects in the calvaria of Wistar rats, for future use in tissue engineering. Experimental sample collections were performed on the 30, 60 and 90th postoperative days, and the analyses performed were histomorphometric, immunohistochemistry, and western blotting. Reducing inflammatory infiltrate in all groups and experimental periods, angiogenesis on the 30th day did not show any difference between the groups, on the 60th day, 5% polycaprolactone/beta-tricalcium phosphate(PCL/β-TCP) was high compared to control (C), and on the 90th day, the same group reduced when compared to C and 10% PCL/β-TCP. The fibroplasia presented oscillations in every segment; on the 30th and 60th day, there was an increase in 5% PCL/β-TCP, which decreased by the 90th day compared to group C. 10% PCL/β-TCP decreased compared to C on the 60th and 90th day. The percentage of the collagen area remained high in all groups and all experimental periods. Immunohistochemistry quantifications showed variations in bone metabolism suggesting new bone formation. The 5 and 10% PCL/β-TCP scaffold were promising for the bone regeneration process because they participated in the modulation of inflammation, angiogenesis, fibroplasia, and collagenosis.

Bone regenerative potential of the selective sphingosine 1-phosphate receptor modulator siponimod: In vitro characterisation using osteoblast and endothelial cells

The repair of critical bone defects remains a significant therapeutic challenge. While the implantation of drug-eluting scaffolds is an option, a drug with the optimal pharmacological properties has not yet been identified. Agents acting at sphingosine 1-phosphate (S1P) receptors have been considered, but those investigated so far do not discriminate between the five known S1P receptors. This work was undertaken to investigate the potential of the specific S1P1/5 modulator siponimod as a bone regenerative agent, by testing in vitro its effect on cell types critical to the bone regeneration process.hFOB osteoblasts and HUVEC endothelial cells were treated with siponimod and other S1P receptor modulators and investigated for changes in intracellular cyclic AMP content, viability, proliferation, differentiation, attachment and cellular motility.Siponimod showed no effect on the viability and proliferation of osteoblasts and endothelial cells, but increased osteoblast differentiation (as shown by increased alkaline phosphatase activity). Furthermore, siponimod significantly increased endothelial cell motility in scratch and transwell migration assays.These effects on osteoblast differentiation and endothelial cell migration suggest that siponimod may be a potential agent for the stimulation of localised differentiation of osteoblasts in critical bone defects.

Intramembranous Ossification Imitation Scaffold with the Function of Macrophage Polarization for Promoting Critical Bone Defect Repair.

The regeneration of craniofacial bone defects remains a crucial clinical challenge. To date, numerous biomaterials are applied in this field. However, current strategies have ignored the importance of intramembranous ossification and the vital role of macrophages in regulating osteogenesis. Here, an osteoblast (OB)-targeting peptide (SDSSD)-modified chitosan scaffold (CS-SDSSD) is developed for imitating the physiological process of bone development from the fibrous membrane. The addition of free peptide (fSDSSD) can recruit host OBs, and the peptide grafted on the scaffold (CS-SDSSD) can well organize the migrated OBs by binding with their surface periostin. Besides, macrophage polarization is found in the bone defects. CS-SDSSD + fSDSSD displays advantages in prioritizing M2 macrophage polarization and promoting the intramembranous ossification bone repair process. In summary, our strategy provides an economical and effective path for craniofacial bone repair and holds great potential for biomedical applications.

Histological Evaluation of a New Beta-Tricalcium Phosphate/Hydroxyapatite/Poly (1-Lactide-Co-Caprolactone) Composite Biomaterial in the Inflammatory Process and Repair of Critical Bone Defects

Background: The use of biomaterials is commonplace in dentistry for bone regeneration. The aim of this study was to evaluate the performance of a new alloplastic material for bone repair in critical defects and to evaluate the extent of the inflammatory process. Methods: Forty-five New Zealand rabbits were divided into five groups according to evaluation time (7, 14, 30, 60, 120 days), totaling 180 sites with six-millimeter diameter defects in their tibiae. The defects were filled with alloplastic material consisting of poly (lactide-co-caprolactone), beta-tricalcium phosphate, hydroxyapatite and nano-hydroxyapatite (BTPHP) in three different presentations: paste, block, and membrane. Comparisons were established with reference materials, such as Bio-ossTM, Bio-oss CollagenTM, and Bio-gideTM, respectively. The samples were HE-stained and evaluated for inflammatory infiltrate (scored for intensity from 0 to 3) and the presence of newly formed bone at the periphery of the defects. Results: Greater bone formation was observed for the alloplastic material and equivalent inflammatory intensity for both materials, regardless of evaluation time. At 30 days, part of the synthetic biomaterial, regardless of the presentation, was resorbed. Conclusions: We concluded that this novel alloplastic material showed osteoconductive potential, biocompatibility, low inflammatory response, and gradual resorption, thus an alternative strategy for guided bone regeneration.