Effect of rhBMP-2 Immobilized Anorganic Bovine Bone Matrix on Bone Regeneration

Dentin, Dentin Graft, and Bone Graft: Microscopic and Spectroscopic Analysis

BACKGROUND

The use of the human dentin matrix could serve as an alternative to autologous, allogenic, and xenogeneic bone grafts. Since 1967, when the osteoinductive characteristics of autogenous demineralized dentin matrix were revealed, autologous tooth grafts have been advocated. The tooth is very similar to the bone and contains many growth factors. The purpose of the present study is to evaluate the similarities and differences between the three samples (dentin, demineralized dentin, and alveolar cortical bone) with the aim of demonstrating that the demineralized dentin can be considered in regenerative surgery as an alternative to the autologous bone.

METHODS

This in vitro study analyzed the biochemical characterizations of 11 dentin granules (Group A), 11 demineralized using the Tooth Transformer (Group B), and dentin granules and 11 cortical bone granules (Group C) using scanning electron microscopy (SEM) and energy dispersive spectroscopy (EDS) to evaluate mineral content. Atomic percentages of C (carbon), O (oxygen), Ca (calcium), and P (phosphorus) were individually analyzed and compared by the statistical t-test.

RESULTS

The significant p-value (p < 0.05) between group A and group C indicated that these two groups were not significantly similar, while the non-significant result (p > 0.05) obtained between group B and group C indicated that these two groups are similar.

CONCLUSIONS

The findings support that the hypothesis that the demineralization process can lead to the dentin being remarkably similar to the natural bone in terms of their surface chemical composition. The demineralized dentin can therefore be considered an alternative to the autologous bone in regenerative surgery.

Effectiveness of Apigenin, Resveratrol, and Curcumin as Adjuvant Nutraceuticals for Calvarial Bone Defect Healing: An In Vitro and Histological Study on Rats

Bone healing is a major clinical issue, especially in bone defects of critical dimensions. Some studies have reported in vivo positive effects on bone healing by some bioactive compounds, such as the phenolic derivatives found in vegetables and plants, such as resveratrol, curcumin, and apigenin. The aim of this work was (1) to analyze in vitro in human dental pulp stem cells the effects of these three natural compounds on the gene expression of related genes downstream to RUNX2 and SMAD5, key factor transcriptions associated with osteoblast differentiation, in order to better understand the positive effects that can occur in vivo in bone healing, and (2) to evaluate in vivo the effects on bone healing of critical-size defects in the calvaria in rats of these three nutraceuticals tested in parallel and for the first time administered by the gastric route. Upregulation of the RUNX2, SMAD5, COLL1, COLL4, and COLL5 genes in the presence of apigenin, curcumin, and resveratrol was detected. In vivo, apigenin induced more consistent significant bone healing in critical-size defects in rat calvaria compared to the other study groups. The study findings encourage a possible therapeutic supplementation with nutraceuticals during the bone regeneration process.

[Advantages and disadvantages of bone graft materials activated by BMP-2 and constructs carrying its gene]

In the review gene constructs and proteins used to impart osteoinductive properties to bone graft materials are compared. On the basis of clinical and experimental data the experience and prospects of their application in maxillofacial surgery and dentistry are described. Information about complications associated with the use of bone morphogenetic protein-2 (BMP-2) and vectors carrying its gene is provided.

Innovative Concepts and Recent Breakthrough for Engineered Graft and Constructs for Bone Regeneration: A Literature Systematic Review

Background: For decades, regenerative medicine and dentistry have been improved with new therapies and innovative clinical protocols. The aim of the present investigation was to evaluate through a critical review the recent innovations in the field of bone regeneration with a focus on the healing potentials and clinical protocols of bone substitutes combined with engineered constructs, growth factors and photobiomodulation applications. Methods: A Boolean systematic search was conducted by PubMed/Medline, PubMed/Central, Web of Science and Google scholar databases according to the PRISMA guidelines. Results: After the initial screening, a total of 304 papers were considered eligible for the qualitative synthesis. The articles included were categorized according to the main topics: alloplastic bone substitutes, autologous teeth derived substitutes, xenografts, platelet-derived concentrates, laser therapy, microbiota and bone metabolism and mesenchymal cells construct. Conclusions: The effectiveness of the present investigation showed that the use of biocompatible and bio-resorbable bone substitutes are related to the high-predictability of the bone regeneration protocols, while the oral microbiota and systemic health of the patient produce a clinical advantage for the long-term success of the regeneration procedures and implant-supported restorations. The use of growth factors is able to reduce the co-morbidity of the regenerative procedure ameliorating the post-operative healing phase. The LLLT is an adjuvant protocol to improve the soft and hard tissues response for bone regeneration treatment protocols.

Osteoinductive Moldable and Curable Bone Substitutes Based on Collagen, BMP-2 and Highly Porous Polylactide Granules, or a Mix of HAP/β-TCP

In dentistry, maxillofacial surgery, traumatology, and orthopedics, there is a need to use osteoplastic materials that have not only osteoinductive and osteoconductive properties but are also convenient for use. In the study, compositions based on collagen hydrogel were developed. Polylactide granules (PLA) or a traditional bone graft, a mixture of hydroxyapatite and β-tricalcium phosphate (HAP/β-TCP), were used for gel filling to improve mechanical osteoconductive properties of compositions. The mechanical tests showed that collagen hydrogels filled with 12 wt% highly porous PLA granules (elastic modulus 373 ± 55 kPa) or 35 wt% HAP/β-TCP granules (elastic modulus 451 ± 32 kPa) had optimal manipulative properties. All composite components were cytocompatible. The cell’s viability was above 90%, and the components’ structure facilitated the cell’s surface adhesion. The bone morphogenetic protein-2 (BMP-2) provided osteoinductive composition properties. It was impregnated directly into the collagen hydrogel with the addition of fibronectin or inside porous PLA granules. The implantation of a collagen hydrogel with BMP-2 and PLA granules into a critical-size calvarial defect in rats led to the formation of the most significant volume of bone tissue: 61 ± 15%. It was almost 2.5 times more than in the groups where a collagen-fibronectin hydrogel with a mixture of HAP/β-TCP (25 ± 7%) or a fibronectin-free composition with porous PLA granules impregnated with BMP-2 (23 ± 8%) were used. Subcutaneous implantation of the compositions also showed their high biocompatibility and osteogenic potential in the absence of a bone environment. Thus, the collagen-fibronectin hydrogel with BMP-2 and PLA granules has optimal biocompatibility, osteogenic, and manipulative properties.

Healing of Experimental Periodontal Defects Following Treatment with Fibroblast Growth Factor-2 and Deproteinized Bovine Bone Mineral

The aim of this study was to investigate the effects of fibroblast growth factor (FGF)-2 used in combination with deproteinized bovine bone mineral (DBBM) on the healing of experimental periodontal defects. Periodontal defects created in rats were treated by FGF-2, DBBM, FGF-2 + DBBM, or left unfilled. Microcomputed tomography, histological, and immunohistochemical examinations were used to evaluate healing. In vitro cell viability/proliferation on DBBM with/without FGF-2 was assessed by WST-1. Cell behavior was analyzed using scanning electron and confocal laser scanning microscopy. Osteogenic differentiation was evaluated by staining with alkaline phosphatase and alizarin red. Bone volume fraction was significantly greater in FGF-2 and FGF-2 + DBBM groups than in other groups at 2 and 4 weeks postoperatively. In histological assessment, newly formed bone in FGF-2 and FGF-2 + DBBM groups appeared to be greater than other groups. Significantly greater levels of proliferating cell nuclear antigen-, vascular endothelial growth factor-, and osterix-positive cells were observed in FGF-2 and FGF-2 + DBBM groups compared to Unfilled group. In vitro, addition of FGF-2 to DBBM promoted cell viability/proliferation, attachment/spreading, and osteogenic differentiation. The combination therapy using FGF-2 and DBBM was similarly effective as FGF-2 alone in the healing of experimental periodontal defects. In certain bone defect configurations, the combined use of FGF-2 and DBBM may enhance healing via promotion of cell proliferation, angiogenesis, and osteogenic differentiation.

Maxillary Sinus Augmentation With Calcium Phosphate Double-Coated Anorganic Bovine Bone: Comparative Multicenter Randomized Clinical Trial With Histological and Radiographic Evaluation

PURPOSE

The purpose of this study was to evaluate the clinical, histological and radiographic outcomes of the calcium phosphate double-coated anorganic bovine bone (InduCera; Oscotec Inc., Seongnam, Gyeonggi, Republic of Korea) compared with that of anorganic bovine bone (Bio-Oss; Geistlich Biomaterials, Wolhusen, Switzerland) in maxillary sinus augmentation, prospectively.

PATIENTS AND METHODS

Twenty-eight sinuses in 25 patients (3 bilateral) with vertical alveolar bone height from 2 to 5 mm were included in this study. The maxillary sinus was augmented with InduCera or Bio-Oss, followed by a healing period of 6 months. Trephine cores were obtained for histomorphometric evaluation with the implant placement. Cone-beam computed tomography (CBCT) scans were taken at 1 week and 6 months after sinus augmentation.

RESULTS

The graft sites were healed without any notable complications in both groups. In histomorphometric analysis, the area of the newly formed bone was measured as 21.37 ± 8.87% for InduCera and 23.02 ± 5.88% for Bio-Oss, with no significant differences. Radiographically, no statistically significant differences were calculated between the groups in bone height at baseline, the height of bone augmentation, the final alveolar bone height (alveolar bone height + augmented height) after 6 months in panoramic radiograph. There were also no significant differences in the shrinkage rate of the grafted area volume in CBCT.

CONCLUSION

Although calcium phosphate double-coated anorganic bovine bone showed no additional effect compared with anorganic bovine bone from a histological and radiographical point of view, it could be used as the bone graft material in maxillary sinus augmentation.

[Safety and efficacy of BMP-2 and BMP-7 use in dentistry]

The article deals with bone morphogenetic proteins BMP-2 and BMP-7 with high osteoinductive potential. The materials containing these proteins are considered. Their safety and efficacy for regeneration of maxillofacial bone defects are evaluated. The prospects of bone tissue regeneration technologies development based on the use of bone morphogenetic proteins are described.

Guided bone regeneration using beta-tricalcium phosphate with and without fibronectin-An experimental study in rats

OBJECTIVE

This histomorphometric study compared bone regeneration potential of beta-tricalcium phosphate with fibronectin (β-TCP-Fn) in critical-sized calvarial defects (CSDs) in rats to assess whether fibronectin (Fn) improved new bone formation.

MATERIAL AND METHODS

Critical-sized calvarial defects were created in 30 adult male Sprague Dawley rats, which were divided into four groups according to the time of euthanasia (6 or 8 weeks of healing) and type of filling (β-TCP-Fn/6 weeks, β-TCP/6 weeks, β-TCP-Fn/8 weeks and β-TCP/8 weeks). The primary variables related to new bone formation were augmented area (AA) and gained tissue (GT; sum of mineralized bone matrix [MBM] and bone substitute [BS]). Secondary variables were the diameter of the defect, MBM, non-mineralized tissue (NMT) and BS.

RESULTS

A total of 29 rats and 58 histological samples were evaluated, 28 (48.3%) samples obtained at 6 weeks and 30 (51.7%) at 8 weeks, homogeneously distributed between right and left sides. Thirteen (22.4%) were treated with β-TCP-Fn, 16 (27.6%) with β-TCP and 29 (50%) were controls. At 8 weeks, histomorphometric analysis showed significant differences in AA using β-TCP and β-TCP-Fn versus controls (p = 0.001 and p = 0.005, respectively). Bone turnover expressed as % within the target area was slightly higher but not statistically significant in the β-TCP-Fn than in β-TCP (MBM) at 6 weeks versus 8 weeks (p = 0.067 and p = 0.335, respectively). Finally, the total GT area in mm² was higher using β-TCP-Fn as compared to β-TCP (p = 0.044).

CONCLUSIONS

β-TCP-Fn was slightly but non-significantly more effective than β-TCP without Fn for improving the volume of regenerated bone in CSDs of rats, possibly allowing a more efficient bone remodelling process. This effect however should continue being investigated.

Restoration of bone defects using modified heterogeneous deproteinized bone seeded with bone marrow mesenchymal stem cells

The aim of the present study was to investigate the effect of modified heterogeneous deproteinized bone combined with bone marrow mesenchymal stem cells (BMSCs) in the restoration of a validated bone defect model. BMSCs were identified by flow cytometry and multilineage differentiation assay. The structural features of the modified heterogeneous deproteinized bone scaffold and biocompatibility between BMSCs and the scaffold were confirmed by scanning electron microscope (SEM) detection. The cytotoxicity of the modified heterogeneous deproteinized bone scaffolds were detected by 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenytetrazolium bromide (MTT) assay. SEM detection proved that modified heterogeneous deproteinized bone scaffold had no negative impact on the proliferation of BMSCs. MTT assay results demonstrated that the scaffold had no apparent cytotoxicity. Biomechanical detection showed that the stiffness and ultimate loading of tibias in the scaffold + BMSCs group were significantly higher than those of the scaffold alone group (P < 0.05) and the control group (P < 0.01). Histological analyses confirmed that the greatest quantity of new bone was generated in the scaffold + BMSCs group, when compared with all other groups, at 8 weeks' post-operation. The bone mineral density (BMD) in the scaffold + BMSC group was significantly higher than that of the scaffold alone group (P < 0.05) and the control group (P < 0.01). Fluorometric analyses confirmed the presence of BMSCs at high concentration within the bone defect areas in the scaffold + BMSCs group at 4 weeks after transplantation. These findings suggest that the modified heterogeneous deproteinized bone scaffold seeded with BMSCs can effectively enhance the restoration of bone defects.

Development and characterization of heparin-immobilized polycaprolactone nanofibrous scaffolds for tissue engineering using gamma-irradiation

Polycaprolactone (PCL) has been considered a useful material for orthopedic devices and osseous implants because of its biocompatibility and bone-forming activity.

Systematical Evaluation of Mechanically Strong 3D Printed Diluted magnesium Doping Wollastonite Scaffolds on Osteogenic Capacity in Rabbit Calvarial Defects

Wollastonite (CaSiO3; CSi) ceramic is a promising bioactive material for bone defect repair due to slightly fast degradation of its porous constructs in vivo. In our previous strategy some key features of CSi ceramic have been significantly improved by dilute magnesium doping for regulating mechanical properties and biodegradation. Here we demonstrate that 6 ~ 14% of Ca substituted by Mg in CSi (CSi-Mgx, x = 6, 10, 14) can enhance the mechanical strength (>40 MPa) but not compromise biological performances of the 3D printed porous scaffolds with open porosity of 60‒63%. The in vitro cell culture tests in vitro indicated that the dilute Mg doping into CSi was beneficial for ALP activity and high expression of osteogenic marker genes of MC3T3-E1 cells in the scaffolds. A good bone tissue regeneration response and elastoplastic response in mechanical strength in vivo were determined after implantation in rabbit calvarial defects for 6‒12 weeks. Particularly, the CSi-Mg10 and CSi-Mg14 scaffolds could enhance new bone regeneration with a significant increase of newly formed bone tissue (18 ~ 22%) compared to the pure CSi (~14%) at 12 weeks post-implantation. It is reasonable to consider that, therefore, such CSi-Mgx scaffolds possessing excellent strength and reasonable degradability are promising for bone reconstruction in thin-wall bone defects.

Bone regenerative effect of recombinant human bone morphogenetic protein-2 after cyst enucleation

Background

The aim of this study is to quantitatively evaluate the effect of rhBMP-2 for repair of bone defects after cyst enucleation using the osteogenesis index (OI).

Methods

Under general anesthesia, 10 patients (12 lesions) underwent oral or maxillofacial surgery for cyst enucleation. Postoperatively, 12 lesions were divided into two groups: group A (six lesions) was treated with absorbable collagen sponge (ACS) in combination with rhBMP-2, and group B (six lesions) was treated with ACS alone. After 3 months, cone-beam computed tomographic scans were obtained to measure changes in the volume of the lesions. We then calculated the OI of each group at two different Hounsfield units to determine any statistically significant difference between these two groups (Mann–Whitney U test).

Results

As tested at the level of new bone, the mean OI was 72.37 % in group A and 55.08 % in group B —a statistically significant difference (p = 0.041). As tested at the level of mature bone, the mean OI was 27.47 % in group A and 18.88 % in group B, but the difference was not statistically significant (p = 0.394).

Conclusions

The application of rhBMP-2 after maxillofacial cyst enucleation accelerated new bone formation in the bone defects. Thus, the use of rhBMP-2 in combination with ACS may be considered an alternative to conventional bone grafting in some patients with postoperative bone defects.

Electronic supplementary material

The online version of this article (doi:10.1186/s40902-016-0070-4) contains supplementary material, which is available to authorized users.

Systematic investigation of β-dicalcium silicate-based bone cements in vitro and in vivo in comparison with clinically applied calcium phosphate cement and Bio-Oss®

Herein we systematically investigated the biological performance of a β-dicalcium silicate (β-C₂S)-based bone cement in comparison with the clinically used calcium phosphate cement (CPC) and Bio-Oss®.

Sequential delivery of BMP-7 and IGF-I to enhance the osteoinductive property of deproteinized bovine bone

Calcium phosphate coated deproteinized bovine bone with sequential delivery of BMP-7 and IGF-I has osteoinductive property to promote bone regeneration.