Synthetic Bone Graft Material Research Articles

The efficiency of two different synthetic bone graft materials on alveolar ridge preservation after tooth extraction: a split-mouth study

BackgroundAlveolar Bone loss occurs frequently during the first six months after tooth extraction. Various studies have proposed different methods to reduce as much as possible the atrophy of the alveolar ridge after tooth extraction. Filling the socket with biomaterials after extraction can reduce the resorption of the alveolar ridge. We compared the height of the alveolar process at the mesial and distal aspects of the extraction site and the resorption rate was calculated after the application of HA/β-TCP or synthetic co-polymer polyglycolic - polylactic acid PLGA mixed with blood to prevent socket resorption immediately and after tooth extraction.MethodsThe study was conducted on 24 extraction sockets of impacted mandibular third molars bilaterally, vertically, and completely covered, with a thin bony layer. HA/β-TCP was inserted into 12 of the dental sockets immediately after extraction, and the synthetic polymer PLGA was inserted into 12 of the dental sockets. All sockets were covered completely with a full-thickness envelope flap. Follow-up was performed for one year after extraction, using radiographs and stents for the vertical alveolar ridge measurements.ResultsThe mean resorption rate in the HA/β-TCP and PLGA groups was ± 1.23 mm and ± 0.1 mm, respectively. A minimal alveolar bone height reduction of HA/β-TCP was observed after 9 months, the reduction showed a slight decrease to 0.93 mm, while this rate was 0.04 mm after 9 months in the PLGA group. Moreover, the bone height was maintained after three months, indicating a good HA/β-TCP graft performance in preserving alveolar bone (1.04 mm) while this rate was (0.04 mm) for PLGA.ConclusionThe PLGA graft demonstrated adequate safety and efficacy in dental socket preservation following tooth extraction. However, HA/β-TCP causes greater resorption at augmented sites than PLGA, which clinicians should consider during treatment planning.

The Osteogenic Peptide P-15 for Bone Regeneration: A Narrative Review of the Evidence for a Mechanism of Action.

Bone regeneration is a complex multicellular process involving the recruitment and attachment of osteoprogenitors and their subsequent differentiation into osteoblasts that deposit extracellular matrixes. There is a growing demand for synthetic bone graft materials that can be used to augment these processes to enhance the healing of bone defects resulting from trauma, disease or surgery. P-15 is a small synthetic peptide that is identical in sequence to the cell-binding domain of type I collagen and has been extensively demonstrated in vitro and in vivo to enhance the adhesion, differentiation and proliferation of stem cells involved in bone formation. These events can be categorized into three phases: attachment, activation and amplification. This narrative review summarizes the large body of preclinical research on P-15 in terms of these phases to describe the mechanism of action by which P-15 improves bone formation. Knowledge of this mechanism of action will help to inform the use of P-15 in clinical practice as well as the development of methods of delivering P-15 that optimize clinical outcomes.

Evaluation optimum ratio of synthetic bone graft material and platelet rich fibrin mixture in a metal 3D printed implant to enhance bone regeneration

BackgroundThis study aims to evaluate the optimal ratio of synthetic bone graft (SBG) material and platelet rich fibrin (PRF) mixed in a metal 3D-printed implant to enhance bone regeneration.MethodsSpecialized titanium hollow implants (5 mm in diameter and 6 mm in height for rabbit; 6 mm in diameter and 5 mm in height for pig) were designed and manufactured using 3D printing technology. The implants were divided into three groups and filled with different bone graft combinations, namely (1) SBG alone; (2) PRF to SBG in 1:1 ratio; (3) PRF to SBG in 2:1 ratio. These three groups were replicated tightly into each bone defect in distal femurs of rabbits (nine implants, n = 3) and femoral shafts of pigs (fifteen implants, n = 5). Animal tissue sections were obtained after euthanasia at the 8th postoperative week. The rabbit specimens were stained with analine blue, while the pig specimens were stained with Masson–Goldner’s trichrome stain to perform histologically examination. All titanium hollow implants were well anchored, except in fracture specimens (three in the rabbit and one fracture in the pig).ResultRabbit specimens under analine blue staining showed that collagen tissue increased by about 20% and 40% in the 1:1 ratio group and the 2:1 ratio group, respectively. Masson–Goldner's trichrome stain results showed that new bone growth increased by 32% in the 1:1 ratio PRF to SBG, while − 8% in the 2:1 ratio group.ConclusionThis study demonstrated that placing a 1:1 ratio combination of PRF and SBG in a stabilized titanium 3D printed implant resulted in an optimal increase in bone growth.

ZnO-doped β-TCP ceramic-based scaffold promotes osteogenic and antibacterial activity

β-Tricalcium phosphate (β-TCP) scaffolds, which are synthetic bone graft materials, have been explored as a potential solution in the healing of bone deformities due to their acceptable degradation rate and ability to support bone growth. However, these scaffolds have limitations such as poor mechanical properties, to stimulate bone growth, which increases the risk of infection after implantation. To overcome these issues, a new type of biomedical scaffold was developed that incorporated zinc oxide (ZnO) particles into β-TCP using wet chemical techniques. The scaffolds were created using sintering to produce porous β-TCP scaffolds with good connectivity. The addition of zinc oxide as a dopant significantly improved the biophysical properties of the scaffolds, with higher concentrations of zinc oxide, leading to better cell adhesion and proliferation. The scaffolds placed in simulated body fluid demonstrated exceptional ability to promote bone growth and regeneration by developing a bone-like apatite layer on their surfaces. The mechanical and physical properties of the scaffolds were effectively assessed using X-ray diffraction and scanning electron microscopy analyses. To validate the efficacy of the specimen in preventing microbial growth and promoting bone growth, a 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide (MTT) test and gene expression investigation were conducted. Zinc oxide-doped β-TCP scaffolds are envisaged to show enormous potential for use in future bone-healing applications.

Effect of a synthetic hydroxyapatite-based bone grafting material compared to established bone substitute materials on regeneration of critical-size bone defects in the ovine scapula.

Lately, the potential risk of disease transmission due to the use of bovine-derived bone substitutes has become obvious, demonstrating the urgent need for a synthetic grafting material with comparable bioactive behaviour and properties. Therefore, the effect of a synthetic hydroxyapatite (HA) (Osbone®) bone grafting material on bone regeneration was evaluated 2 weeks, 1 month, and 3, 6, 12 and 18 months after implantation in critical-size bone defects in the ovine scapula and compared to that of a bovine-derived HA (Bio-Oss®) and β-tricalcium phosphate (TCP) (Cerasorb® M). New bone formation and the biodegradability of the bone substitutes were assessed histomorphometrically. Hard tissue histology and immunohistochemical analysis were employed to characterize collagen type I, alkaline phosphatase, osteocalcin, as well as bone sialoprotein expression in the various cell and matrix components of the bone tissue to evaluate the bioactive properties of the bone grafting materials. No inflammatory tissue response was detected with any of the bone substitute materials studied. After 3 and 6 months, β-TCP (Cerasorb® M) showed superior bone formation when compared to both HA-based materials (3 months: β-TCP 55.65 ± 2.03% vs. SHA 49.05 ± 3.84% and BHA 47.59 ± 1.97%; p ≤ 0.03; 6 months: β-TCP 62.03 ± 1.58%; SHA: 55.83 ± 2.59%; BHA: 53.44 ± 0.78%; p ≤ 0.04). Further, after 12 and 18 months, a similar degree of bone formation and bone-particle contact was noted for all three bone substitute materials without any significant differences. The synthetic HA supported new bone formation, osteogenic marker expression, matrix mineralization and good bone-bonding behaviour to an equal and even slightly superior degree compared to the bovine-derived HA. As a result, synthetic HA can be regarded as a valuable alternative to the bovine-derived HA without the potential risk of disease transmission.

Special at-rich sequence-binding protein 2 and its role in healing of the experimental mandible bone tissue defect filling with a synthetic bone graft material and electrical stimulation impact.

Aim: The purpose of the study was to identify the role of SATB2 in healing of the experimental mandible bone tissue defect filling with a synthetic bone graft material and electrical stimulation impact. Materials and Methods: An experiment was carried out on 48 mature male rats of the WAG population, which were divided into 4 groups. Each group included 12 experimental animals. Group 1 included rats that were modeled with a perforated defect of the lower jaw body. Group 2 included animals that were modeled with a perforated defect similar to group 1. In animals, a microdevice for electrical action was implanted subcutaneously in the neck area on the side of the simulated bone defect. The negative electrode connected to the negative pole of the battery was in contact with the bone defect. The battery and electrode were insulated with plastic heat shrink material. Group 3 included rats that were modeled with a perforated defect similar to previous groups, the cavity of which was filled with synthetic bone graft "Biomin GT" (RAPID, Ukraine). Group 4 included animals that were modeled with a perforated defect similar to groups 1-3, the cavity of which was filled with synthetic bone graft "Biomin GT" (RAPID, Ukraine). The simulation of electrical stimulation was the same as in group 2. The material for the morphological study was a fragment of the body of the lower jaw from the zone of the perforated defect. Immunohistochemical study was performed using rabbit anti-human SATB2 monoclonal antibody. Results: In the regenerate filling the defect in the bone tissue of the lower jaw of rats, there was an increase in SATB2 expression under conditions of electrical stimulation; filling the defect with a synthetic bone graft material; simultaneous filling the defect with a synthetic bone graft material and electrical stimulation. The most pronounced expression of SATB2 was observed under conditions of simultaneous filling the defect with a synthetic bone graft material and electrical stimulation; minimally expressed - in conditions of filling the defect with a synthetic bone graft material; moderately expressed - under conditions of electrical stimulation. In the regenerate, in cases of all treatment methods, SATB2 was expressed by immune cells, fibroblastic differon cells, osteoblasts, and in case of electrical stimulation, also by adipocytes, vascular pericytes and endothelial cells, epidermis. Conclusions: The activation of SATB2 expression identified by the authors is one of the mechanisms for stimulating reparative osteogenesis under the conditions of electrical stimulation; filling the defect with a synthetic bone graft material; simultaneous filling the defect with a synthetic bone graft material and electrical stimulation.

Outcome of Multilevel Anterior Cervical Discectomy and Fusion without Plating

Background: Multilevel anterior cervical discectomy and fusion (ACDF) procedure had traditionally been associated with plating, however, the increase in cost and complications associated with plating led us to investigate results of multilevel ACDF with polyether ether ketone (PEEK) cages without plating and study complication and fusion rates.
 Objective: To evaluate the clinical and radiological outcome of patients underwent multilevel Anterior Cervical Discectomy and Fusion (ACDF) using polyether ether ketone (PEEK) cage with no plating.
 Patients and Methods: Sixty patients underwent multilevel Anterior Cervical Discectomy and Fusion (ACDF), Surgical approach, using Polyether Ether Ketone (PEEK) cages with synthetic bone graft material with no plating. Their mean age was 48 year. All patients were evaluated clinically and radiologically for a mean time of one year. Assessment done comparing early and late post-operative cervical spinal x-rays for cage subsidence and migration. Improvement in axial neck and radicular pain were assessed using the Visual Analogue Score (VAS). Statistical analysis was performed using the Statistical Package for Social Sciences (SPSS), A p value of ≤ 0.05 was considered statistically significant.
 Results: Sixty patients underwent Anterior Cervical Discectomy with Fusion (ACDF) through Cloward approach. F:M ratio was 1:1. Two levels were operated in 75% of patients, while in 25% three levels were operated. The majority 85% underwent operation at C5-6 level, least operated levels were C3-C4 and C6-C7 36.7% and 66.7% underwent operation at C4-C5 level. None underwent operation at C2-C3 level. There was significant improvement in axial neck pain with VAS decreasing from 6 to 2, radicular pain improved from 7 to 2. Only one patient (1.7%) showed radiological subsidence of 3 mm after 6 months of operation with no further progression, cage slippage was observed in 2 patients (3.3%) by 1 mm in both cases but no radiological progression. All patients (100%) showed good fusion.
 Conclusion: Multilevel ACDF with PEEK cages without plating showed to be safe option and provided good fusion rates and clinical outcome in our patients.

Outcome of Multilevel Anterior Cervical Discectomy and Fusion without Plating

Background: Multilevel anterior cervical discectomy and fusion (ACDF) procedure had traditionally been associated with plating, however, the increase in cost and complications associated with plating led us to investigate results of multilevel ACDF with polyether ether ketone (PEEK) cages without plating and study complication and fusion rates. Objective: To evaluate the clinical and radiological outcome of patients underwent multilevel Anterior Cervical Discectomy and Fusion (ACDF) using polyether ether ketone (PEEK) cage with no plating. Patients and Methods: Sixty patients underwent multilevel Anterior Cervical Discectomy and Fusion (ACDF), Surgical approach, using Polyether Ether Ketone (PEEK) cages with synthetic bone graft material with no plating. Their mean age was 48 year. All patients were evaluated clinically and radiologically for a mean time of one year. Assessment done comparing early and late post-operative cervical spinal x-rays for cage subsidence and migration. Improvement in axial neck and radicular pain were assessed using the Visual Analogue Score (VAS). Statistical analysis was performed using the Statistical Package for Social Sciences (SPSS), A p value of ≤ 0.05 was considered statistically significant. Results: Sixty patients underwent Anterior Cervical Discectomy with Fusion (ACDF) through Cloward approach. F:M ratio was 1:1. Two levels were operated in 75% of patients, while in 25% three levels were operated. The majority 85% underwent operation at C5-6 level, least operated levels were C3-C4 and C6-C7 36.7% and 66.7% underwent operation at C4-C5 level. None underwent operation at C2-C3 level. There was significant improvement in axial neck pain with VAS decreasing from 6 to 2, radicular pain improved from 7 to 2. Only one patient (1.7%) showed radiological subsidence of 3 mm after 6 months of operation with no further progression, cage slippage was observed in 2 patients (3.3%) by 1 mm in both cases but no radiological progression. All patients (100%) showed good fusion. Conclusion: Multilevel ACDF with PEEK cages without plating showed to be safe option and provided good fusion rates and clinical outcome in our patients. Keywords: Cervical spondylosis, Multilevel ACDF, ACDF without plating, Subsidence, Migrati on.

Polymethylmethacrylate-hydroxyapatite antibacterial and antifungal activity against oral bacteria: An in vitro study

ObjectiveReconstruction of alveolar bone defects resulting from aging, trauma, ablative surgery or pathology, remains a significant clinical challenge. The objective of this study was to investigate the antibacterial and antifungal activities of mixed polymethylmethacrylate-hydroxyapatite (PMMA-HA) against oral microorganisms. Our findings could provide valuable insights into the prospective application of PMMA-HA as a synthetic bone graft material to manage alveolar bone defects via tissue engineering. MethodsHA powder was obtained from the Center for Ceramics in Indonesia and PMMA granules were obtained from HiMedia Laboratories; these were prepared in 20:80, 30:70, and 40:60 ratios. The antibacterial diffusion method was then performed against Staphylococcusaureus, Aggregatibacter actinomycetemcomitans, Porphyromonas gingivalis, and Fusobacterium nucleatum, while the antifungal diffusion method was used to test against Candida albicans. Standardized protocols were used for microbial culturing and inhibition zones were measured with digital calipers. Statistical analyses included one-way ANOVA and Kruskal–Wallis tests, supplemented by post-hoc Tukey HSD tests. ResultsA PMMA-HA scaffold with a 20:80 ratio demonstrated the highest antibacterial activity against S. aureus, A. actinomycetemcomitans, P. gingivalis, and F. nucleatum. This was followed by the 30:70 and 40:60 ratios in terms of antibacterial activity. Statistical significance was achieved with p < 0.05 in comparison to controls. However, none of the PMMA-HA ratios showed antifungal activity against C. albicans. ConclusionPMMA-HA scaffolds have significant activity against bacteria, but not against fungi.

Synthetic Calcium-Phosphate Materials for Bone Grafting.

Synthetic bone grafting materials play a significant role in various medical applications involving bone regeneration and repair. Their ability to mimic the properties of natural bone and promote the healing process has contributed to their growing relevance. While calcium-phosphates and their composites with various polymers and biopolymers are widely used in clinical and experimental research, the diverse range of available polymer-based materials poses challenges in selecting the most suitable grafts for successful bone repair. This review aims to address the fundamental issues of bone biology and regeneration while providing a clear perspective on the principles guiding the development of synthetic materials. In this study, we delve into the basic principles underlying the creation of synthetic bone composites and explore the mechanisms of formation for biologically important complexes and structures associated with the various constituent parts of these materials. Additionally, we offer comprehensive information on the application of biologically active substances to enhance the properties and bioactivity of synthetic bone grafting materials. By presenting these insights, our review enables a deeper understanding of the regeneration processes facilitated by the application of synthetic bone composites.

Long-term results comparison after anterior cervical discectomy with BGS-7 spacer (NOVOMAX®-C) and allograft spacer: A prospective observational study.

Introduction: In an anterior cervical discectomy and fusion (ACDF), various types of graft materials including autograft, allograft, and synthetic graft have been used to achieve adequate spinal fusion. Allograft spacer is mainly used in cervical fusion, especially in the anterior approach. The synthetic bone graft material BGS-7(CaO-SiO2-P2O5-B2O3, bioactive Glass-Ceramics) can bind with surrounding bone tissue by forming a hydroxyapatite layer bone bridge, leading to faster graft osseointegration. This study was conducted to compare long-term clinical outcome of BGS-7 spacer and allograft spacer for anterior cervical discectomy and fusion surgery. Materials and Methods: From September 2014 to December 2016, Consecutive anterior cervical discectomy and fusion surgeries using a BGS-7 spacer (N = 18) and Allograft spacer (N = 26) were compared for postoperative clinical outcomes. Radiologic assessments were performed, and Instrumental failure, including breakage, cage migration, subsidence were observed and Fusion status were analyzed. Finite element analysis was performed for simulating mechanical stress between the vertebral body and implant. Clinical outcomes were evaluated using neck VAS, NDI, and JOA on the patient's final follow-up visits. Results: Among the 44 patients who underwent an anterior cervical discectomy and fusion surgery using the BGS-7 spacer and Allograft spacer, there were 30 men and 14 women. The average age at the operation was 47.69 ± 10.49 in allograft spacer and 51.67 ± 11.03 in BGS-7 spacer. The mean follow-up period was 89.18 ± 5.44months. Twenty three (88.46%) patients in allograft spacer and 20(100%) patients in BGS-7 spacer were demonstrated radiologic evidence of interbody fusion in last OPD, which accounts for fusion grade 4 or 5. Peak stresses were 343.85MPa in allograft spacer, and 132.55MPa in BGS-7 spacer. Long-term clinical outcomes including neck VAS, NDI, and JOA didn't show statistical differences between the two groups. There were no adverse events related to the BGS-7 spacer.10.3389/fbioe.2023.110046. Conclusion: The BGS-7 spacer demonstrated reliability as a spacer in anterior cervical discectomy and fusionF surgery without instrumental failure. Early stabilization with a bony bridge formation was observed at the intermediate follow-up period, and the long-term clinical outcome was favorable at more than 60months after surgery without any adverse events. Thus, the BGS-7 spacer is a safe and effective alternative to the allograft spacer in anterior cervical discectomy and fusion surgery.

Novel Synthetic Carbonate Apatite as a Bone Substitute in Implant Treatments: Case Reports.

Bone graft materials are often used in implant treatment to optimize functional and esthetic outcomes. The requirements for bone grafting materials are the ability to maintain space for bone regeneration to occur and the capability of being resorbed by osteoclasts and replaced with new bone tissue occurring in passive chemolysis and bone remodeling. Carbonate apatite (CO3Ap) granules (Cytrans Granules, GC) are a chemically synthetic bone graft material similar to autogenous bone minerals and more biocompatible than allografts and xenografts. The aim of this report is to evaluate the efficacy of CO3Ap granules in implant treatments when used alone or in combination with autogenous bone. The clinical findings and the radiographic and histologic assessments in three cases of immediate implant placement and lateral and vertical guided bone regeneration are reported. Despite the short-term follow-ups, histologic findings showed that CO3Ap granules were efficiently resorbed and replaced bone in clinical use. Furthermore, the clinical findings showed that CO3Ap granules maintained their morphology around the implant. This limited short-term case report suggests that this bone substitute is effective. However, further clinical studies and long-term reports of this new biomaterial are needed.

Lithium doped biphasic calcium phosphate: Structural analysis and osteo/odontogenic potential in vitro.

Biphasic calcium phosphate (BCP) is generally considered a good synthetic bone graft material with osteoinductive potential. Lithium ions are trace elements that play a role in the bone-remodeling process. This study aimed to investigate the effects of lithium ions on the phase, crystal structure, and biological responses of lithium doped BCPs and to identify improvements in their osteogenic properties. Lithium-doped BCP powders with different doping levels (0, 5, 10, and 20 at%) were synthesized via the co-precipitation method. We found that the four types of lithium-doped BCP powders showed different phase compositions of hydroxyapatite and β-tricalcium phosphate. In addition, lithium ions favored entering the β-tricalcium phosphate structure at the Ca (4) sites and calcium vacancy sites [VCa(4)] up to 10 at%. This substitution improves the crystal stabilization by filling the vacancies with Ca2+ and Li+ in all Ca sites. However, when the concentration of Li ions was higher than 10 at%, lithium-induced crystal instability resulted in the burst release of lithium ions, and the osteogenic behavior of human dental pulp stem cells did not improve further. Although lithium ions regulate osteogenic properties, it is important to determine the optimal amount of lithium in BCPs. In this study, the most effective lithium doping level in BCP was approximately 10 at% to improve its biological properties and facilitate medical applications.

Safety and Efficacy of a New Moldable and Compression Resistant Matrix Carrier with Recombinant Human Bone Morphogenetic Protein-2 in the Rabbit Bone Defect Model.

To conduct an animal experimental study to evaluate the safety and efficacy of the compression-resistant matrix (CRM) carrier for recombinant human bone morphogenetic protein-2 (rhBMP-2) in osteogenesis. New moldable CRM carrier, and with rhBMP-2 (new CRM carrier with rhBMP-2) were prepared as the experimental groups. Pre-existing synthetic bone graft material was prepared as a control graft group. A total of 24 rabbits were included in the study. Defects were made and grafts were performed, and radiographic and histopathologic findings were evaluated to assess fusion. In the computed tomographic scan, new bone formation was superior in 16.0%, 39.3%, 64.7%, and 81.1% of the total defect volume at 4, 8, 12, and 16 weeks in the new CRM carrier with rhBMP-2 group. In the new CRM carrier group, new bone formation was observed in 10.6%, 26.3%, 53.1%, and 71.4%, respectively. In the control graft group, new bone formation was observed in 10.1%, 26.6%, 53.4%, and 72.1%, respectively. On histopathologic evaluation, new CRM carrier with rhBMP-2 group showed better new bone formation compared with those of other groups. The new moldable CRM carrier and the CRM carrier with rhBMP-2 showed preclinical safety and efficacy in new bone formation. In particular, the CRM carrier with rhBMP-2 was considered to be an effective bone graft material for bone fusion.

Transforming the Degradation Rate of β-tricalcium Phosphate Bone Replacement Using 3-Dimensional Printing.

β-Tricalcium phosphate (β-TCP) is one of the most common synthetic bone grafting materials utilized in craniofacial reconstruction; however, it is limited by a slow degradation rate. The aim of this study was to leverage 3-dimensional (3D) printing in an effort to accelerate the degradation kinetics of β-TCP. Twenty-two 1-month-old New Zealand white rabbits underwent creation of calvarial and alveolar defects, repaired with 3D-printed β-TCP scaffolds coated with 1000 μM of osteogenic agent dipyridamole. Rabbits were euthanized after 2, 6, and 18 months after surgical intervention. Bone regeneration, scaffold degradation, and bone mechanical properties were quantified. Histological analysis confirmed the generation of vascularized and organized bone. Microcomputed tomography analysis from 2 to 18 months demonstrated decreased scaffold volume within calvarial (23.6% ± 2.5%, 5.1% ± 2.2%; P < 0.001) and alveolar (21.5% ± 2.2%, 0.2% ± 1.9%; P < 0.001) defects, with degradation rates of 54.6%/year and 90.5%/year, respectively. Scaffold-inducted bone generation within the defect was volumetrically similar to native bone in the calvarium (55.7% ± 6.9% vs 46.7% ± 6.8%; P = 0.064) and alveolus (31.4% ± 7.1% vs 33.8% ± 3.7%; P = 0.337). Mechanical properties between regenerated and native bone were similar. Our study demonstrates an improved degradation profile and replacement of absorbed β-TCP with vascularized, organized bone through 3D printing and addition of an osteogenic agent. This novel additive manufacturing and tissue engineering protocol has implications to the future of craniofacial skeletal reconstruction as a safe and efficacious bone tissue engineering method.

Transforming the Degradation Rate of β-tricalcium Phosphate Bone Replacement Using 3D Printers

Statement of the problemCraniofacial injuries often require resection of necrotic hard tissue. For large bone defects, autogenous bone grafting is ideal, but as is the case with all grafting procedures, is subject to limitations on quantity. Synthetic biomaterial driven three-dimensional (3D) printing technology of solid-free form fabrication (SFF) offers an alternative engineered healing approach. This research hypothesizes that a bioactive calcium-phosphate scaffold may successfully regenerate craniofacial bony defects in vivo, and that this newly formed bone will have mechanical properties similar to native bone as healing time elapses in vivo. The aim of this study was to leverage 3D printing of β-tricalcium phosphate (β-TCP), a common synthetic bone grafting material, to accelerate degradation kinetics of β-TCP while allowing for optimal bone regeneration/remodeling and bone mechanical properties. Materials and methodsTwenty-two 1-month-old New Zealand White rabbits underwent creation of calvarial and alveolar defects, repaired with 3D-printed β-TCP scaffolds coated with 1,000 μM of osteogenic agent dipyridamole. Rabbits were euthanized after 2, 6, and 18 months post-surgical intervention. Bone regeneration, scaffold degradation, and bone mechanical properties were quantified. ResultsHistology analysis confirmed the generation of vascularized and organized bone. Micro CT analysis from 2 to 18 months, demonstrated decreased scaffold volume within calvarial (23.6% ±2.5%, 5.1%±2.2%; P < .001) and alveolar (21.5%±2.2%, 0.2%±1.9%; P < .001) defects, with degradation rates 54.6%/year and 90.5%/year, respectively. Scaffold-inducted bone generation within the defect was volumetrically similar to native bone in the calvarium (55.7%±6.9% vs. 46.7%±6.8%; P = .064) and alveolus (31.4%±7.1% vs. 33.8%±3.7%; P = .337). Mechanical properties between regenerated and native bone were similar. Outcomes and conclusionThis study demonstrates an improved degradation profile and replacement of absorbed β-TCP with vascularized, organized bone through 3D printing, and the addition of an osteogenic agent. This novel additive manufacturing and tissue-engineering protocol has implications for the future of craniofacial skeletal reconstruction as a safe and efficacious bone tissue-engineering method.

Hydroxyapatite cages with aligned pores for bone grafting – Seeding of human osteoblast-like cells in vitro and their response in dynamic culture mode

Hydroxyapatite (HA) is a highly regarded synthetic bone graft material. Porous HA ceramics blocks are used to substitute harvested natural bone grafts. Being similar to bone mineral, HA material integrates with the host bone through surface osteointegration and slowly resorb along with the natural bone remodeling process. The blocks in use currently have random and tortuous pore structures. The present work explores the usefulness of cage-like HA ceramic design with end-to-end open pores, with the help of in vitro cell culture methods. Such a structure, on implantation, will take up the blood factors and cells and host the bone remodeling process inside the bulk of the cage, leading to early healing. In the study, HA samples with aligned through-pores were prepared and explored in vitro, with a focus on how the pores host the cells inside and to what level the cells maintain their activity. Human osteoblast-like cells (HOS) were used, at different seeding and culturing approaches. Cell seeding was done through (i) conventional large volume cell suspension, (ii) a confined mini chamber with a limited volume of cell suspension, and (iii) placing a concentrated drop of cell suspension directly on top of the scaffold. The third approach gave the best cell adhesion and proliferation, and hence used for further explorations. A dynamic culture system was designed in-house by bifurcating the cell culture wells using vertical inserts, holding the samples horizontally with their ends open to both sides, and making the media flow across using a rocker platform. The HOS cell adhesion, viability and proliferation were tested in the HA cages, in static and dynamic culture conditions, with conventional porous ceramics as the control. The cell infiltration was deeper and the cell viability over a period of 7 days was significantly higher in dynamic culture conditions in the test samples.

Ionic substituted hydroxyapatite for bone regeneration applications: A review

Biological apatites are characterised by various ionic substitutions within the HAp lattice that are crucial for bone metabolism. The introduction of key role elements within synthetic calcium phosphates (CaP), mainly hydroxyapatite (HAp), can increase osteogenesis and enhance bone regeneration process. The lattice structure of HAp enables cationic and anionic substitutions leading to the enhanced biological performance of synthetic bone graft materials. This review summarises recent and relevant studies on cationic and anionic substitutions in the HAp lattice that are commonly found in the human body. Furthermore, co-substituted HAp obtained from synthetic and biological precursors, along with their influence on the bone regeneration process, has been discussed. Finally, future perspectives for the use of substituted HAp have been presented.

A Prospective, Multi-Center, Double-Blind, Randomized Study to Evaluate the Efficacy and Safety of the Synthetic Bone Graft Material DBM Gel with rhBMP-2 versus DBM Gel Used during the TLIF Procedure in Patients with Lumbar Disc Disease.

ObjectiveThis study is to evaluate the efficacy and safety of demineralized bone matrix (DBM) gel versus DBM gel with recombinant human bone morphogenetic protein-2 (rhBMP-2) used in transforaminal lumbar interbody fusion (TLIF). MethodsThis study was designed as a prospective, multi-center, double-blind method, randomized study. All randomized subjects underwent TLIF with DBM gel with rhBMP-2 group (40 patients) as an experimental group or DBM gel group (36 patients) as a control group. Post-operative observations were performed at 12, 24, and 48 weeks. The spinal fusion rate on computed tomography scans and X-rays films, Visual analog scale pain scores, Oswestry disability index and SF-36 quality of life (QOL) scores were used for the efficacy evaluation. The incidence rate of adverse device effects (ADEs) and serious adverse device effects (SADEs) were used for safety evaluation. ResultsThe spinal fusion rate at 12 weeks for the DBM gel with rhBMP-2 group was higher with 73.68% compared to 58.82% for the DBM gel group. The 24 and 48 weeks were 72.22% and 82.86% for the DBM gel with rhBMP-2 group and 78.79% and 78.13%, respectively, for the DBM gel group. However, there were no significant differences between two groups in the spinal fusion rate at 12, 24, and 48 weeks post-treatment (p=0.1817, p=0.5272, p=0.6247). There was no significant difference between the two groups in the incidence rate of ADEs (p=0.3836). For ADEs in the experimental group, ‘Pyrexia’ (5.00%) was the most common ADE, followed by ‘Hypesthesia’, ‘Paresthesia’, ‘Transient peripheral paralysis’, ‘Spondylitis’ and ‘Insomnia’ (2.50%, respectively). ADEs reported in control group included ‘Pyrexia’, ‘Chest discomfort’, ‘Pain’, ‘Osteoarthritis’, ‘Nephropathy toxic’, ‘Neurogenic bladder’, ‘Liver function analyses’ and ‘Urticaria’ (2.86%, respectively). There was no significant difference between the two groups in the incidence rate of SADEs (p=0.6594). For SADE in the experimental group, ‘‘Pyrexia’ and ‘Spondylitis’ were 2.50%. SADE reported in the control group included 'Chest discomfort’, ‘Osteoarthritis’ and ‘Neurogenic bladder’. All SADEs described above were resolved after medical treatment. ConclusionThis study demonstrated that the spinal fusion rates of DBM gel group and DBM gel with rhBMP-2 group were not significantly different. But, this study provides knowledge regarding the earlier postoperative effect of rhBMP-2 containing DBM gel and also supports the idea that the longer term follow-up results are essential to confirm the safety and effectiveness.

Clinical Safety Assessment of Autologous Freeze-Drying Platelet-Rich Plasma for Bone Regeneration in Maxillary Sinus Floor Augmentation: A Pilot Study.

The purpose of this clinical study is to evaluate the safety and preliminary efficacy of autologous freeze-drying platelet-rich plasma (FD-PRP) on bone regeneration in maxillary sinus floor augmentation as a preliminary pilot study. Five patients that required sinus floor augmentation to facilitate the placement of dental implants participated in this clinical study. The PRP was prepared from the autologous peripheral blood and was lyophilized and stored at −20 °C for 4 weeks before surgery. At surgery, triple-concentrated FD-PRP (x3FD-PRP) mixed with synthetic bone grafting materials was rehydrated following the transplantation into the sinus floor. The primary outcome was a safety verification of x3FD-PRP, evaluated in terms of the clinical course and consecutive blood tests. The secondary outcome was clinical efficacy focused on bone regeneration in sinus floor augmentation evaluated by radiographic examination and implant stability. There were no adverse events, such as systemic complications, excessive inflammatory reactions, severe infection, or local site healing complications, besides those on the usual course associated with surgery. Vertical augmented height was maintained, and the initial stability of implants was achieved post-operatively in 6 months. The results obtained in this study suggest that x3FD-PRP can be used safely for bone engineering in clinical practice. Further studies are required to draw a conclusion concerning the efficacy of x3FD-PRP since this was a pilot study with a single arm and a small sample size.