Coralline Hydroxyapatite Research Articles

Bone marrow mesenchymal stem cell sheets with high expression of hBD3 and CTGF promote periodontal regeneration

The multi-bacterial environment of the oral cavity makes it hard for periodontal regeneration. As a class of antimicrobial peptide, beta defensin has been found to show broad-spectrum antibacterial ability. In addition, connective tissue growth factor (CTGF) is demonstrated to play a great role in multi-physiological events such as angiogenesis, wound healing and, more importantly, fibrogenesis. In this study, human β defensin 3 (hBD3) and CTGF were co-transfected into bone marrow derived mesenchymal stem cells (BMSCs) for preparing cell sheets. The transfection efficiency was detected through fluorescence of eGFP and western blot assay. Our results showed that the hBD3 and CTGF proteins were highly and stably expressed in the BMSCs after transfection. The results of RT-PCR and induced differentiation indicated that hBD3 promoted osteogenic differentiation of BMSCs, while CTGF significantly increased fibrogenic differentiation even in the presence of hBD3. The BMSCs acquired stronger capacity in terms of promoting M2 polarization of RAW 264.7 macrophages fulfilled by the transfection and secretion of hBD3 and CTGF. To further evaluate the periodontal remodeling performance of cell sheets, a coralline hydroxyapatite (CHA)-chitosan based hydrogel-human tooth system was designed to simulate the natural periodontal environment. The results showed that dense extracellular matrix, oriented fiber arrangement, and abundant collagen deposition appeared in the area of BMSCs sheets after subcutaneous transplantation. Altogether, our data showed that the lentivirus transfected BMSCs sheets had a promising application prospect for periodontal repair.

Coralline Hydroxyapatite Coated with a Layer Biomimetic Calcium Phosphate Containing BMP-2 Induces Dose-Related Ectopic Bone Formation in Wistar Rats

In order to evaluate loading methods and the dose dependency of bone morphogenetic protein 2 (BMP-2) in ectopic bone formation, an osteoinductive material consisting of commercially available coralline hydroxyapatite (CHA) was coated with a layer of biomimetic calcium phosphate (BioCaP) containing BMP-2 in different ways. Eight groups—each containing samples of 0.25 g CHA—were formed and coated with, respectively, BioCaP with internally incorporated BMP-2 in concentrations of 1, 5, 10, 20, 40 and 60 µg per sample, and the two control groups with BioCaP only and BioCaP with 20 µg of adsorbed BMP-2 per sample. The samples were implanted subcutaneously in 27 male Wistar rats. The histological results show that there is no bone formation in the group in which no BMP-2 was included. All samples with BioCaP containing BMP-2 show bone formation. The group with 20 µg of adsorbed BMP-2 per sample shows the least bone formation. Coating-incorporated BMP-2 is more efficient in inducing bone formation than adsorbed BMP-2. The group with 5 µg of coating-incorporated BMP-2 per sample shows the most bone formation. Increasing the amount of coating-incorporated BMP-2 up to 60 µg does not improve ectopic bone formation.

Case Series: Use of Coralline Hydroxyapatite Graft In Faciomaxillary Surgery

Bone grafting represents an important solution for defects in maxillofacial and orthopaedic surgeries. Ideal properties of a bone graft allow proper integration, enabling cosmetic appeal and mechanical functionality. Whilst current autograft, allograft and xenograft applications do exist and are regularly used clinically, they are associated with numerous solutions, such as availability, disease transmission and donor site morbidity. Synthetic and naturally sourced solutions can avoid these issues, whilst maintaining the ideal bone integrative properties of their autograft counterparts. This case series aims to identify the effectiveness of a natural bone graft substitute, coralline hydroxyapatite, in maxillofacial applications, and demonstrate that coralline hydroxyapatite encourages bone ingrowth for dental defects.

Mandibular bone regeneration with autologous adipose-derived mesenchymal stem cells and coralline hydroxyapatite: experimental study in rats

The purpose of this paper was to investigate the bone regeneration effect of autologous adipose tissue mesenchymal stem cells (ATMSC) in a small animal model. Twelve Wistar rats were given bilateral critical-size defects in the mandible. The defects were filled with coralline hydroxyapatite alone or combined with autologous undifferentiated ATMSC obtained from the dorsal fat pad. Studies were conducted at three and six weeks. Descriptive histology and histomorphometry revealed a significant (p < 0.05) increased bone regeneration values in the cell-treated defects at both three and six weeks. ATMSC promoted the formation of new bone in the central areas of the defects and in the scaffold micropores, both in a higher state of maturation. Autologous undifferentiated ATMSC enhanced bony healing of mandibular critical-size defects in rats when implanted with a coralline hydroxyapatite scaffold.

Coralline Hydroxyapatite Bone Graft in Non-Contained Defects: Case Report

Coralline Hydroxyapatite Bone Graft in Non-Contained Defects: Case Report

Preparation of Coralline Hydroxyapatite Implant with Recombinant Human Bone Morphogenetic Protein-2-Loaded Chitosan Nanospheres and Its Osteogenic Efficacy.

ObjectiveSpinal fusion is one of the most common surgical interventions for spine reconstruction. Despite the efforts to promote osteogenesis after spinal fusion, osteogenesis after spinal fusion remains a clinical challenge and new methods are still needed. The bone morphogenetic protein‐2 (BMP‐2) is a widely reported factor that can facilitate the osteogenesis in spinal fusion. In previous research, we found that the delivery of chitosan nanospheres could promote the effects of BMP‐2 on osteogenic activity. The coralline hydroxyapatite (CHA) is one of the most frequently used implants in bone fusion. However, up to now no study has focused on the osteogenic efficacy of the CHA composite with recombinant human BMP‐2 (rhBMP‐2)‐loaded chitosan nanospheres. This study aimed to investigate the effects of the CHA implant with rhBMP‐2‐loaded chitosan nanospheres on osteogenesis in spinal fusion.MethodsThe rhBMP‐2‐loaded microspheres and CHA composite (rhBMP‐2 microspheres/CHA) were prepared and were used for implantation of the rats. All SD rats were divided into four groups: the rhBMP‐2 microspheres/CHA composite group (containing 0.5 mg rhBMP‐2), the rhBMP‐2‐loaded CHA (rhBMP‐2/CHA) composite group (containing 0.5 mg rhBMP‐2), the blank CHA group, and the negative control group. The microsphere morphology was scanned and analyzed using a scanning electron microscope. Micro‐computed tomography examination and three‐dimensional reconstruction were performed 4 weeks after the surgery. Hematoxylin and eosin staining was conducted for histological analysis. Both alkaline phosphatase (ALP) and calcium content were measured.ResultsThe rhBMP‐2‐loaded CHA (rhBMP‐2/CHA) composite was successfully prepared. Spherical regularity and a smooth and unwrinkled surface of the spheres were observed in all chitosan (CS)/rhBMP‐2 microspheres. No side effects, infections, or abnormal behaviors were found in the animals. After 4 weeks of surgery, obvious new bone formation and bone fusion could be observed around the implant in both the rhBMP‐2 microspheres/CHA composite group and the rhBMP‐2/CHA composite group. No ectopic osteogenesis was found in the vertebral canal or other muscle tissues. After 4 weeks of implantation, in both the rhBMP‐2 microspheres/CHA composite group and the rhBMP‐2/CHA composite group, osteoid tissues could be found, and bone cells, bone marrow, and trabecular bone turned into mature sclerotin, obvious bone tissue formation could be also seen. Both ALP activity and calcium content in the rhBMP‐2 microspheres/CHA composite group (6.52 ± 0.50 kat/g and 17.54 ± 2.49 μg/mg) were significantly higher than in all other groups.ConclusionThe composite with rhBMP‐2‐loaded CS nanospheres could enhance osteogenic efficacy and increase the ALP activity and calcium content. These results might provide a novel method for osteogenesis in spinal fusion and offer new insight into the role of BMP‐2 in osteogenesis.

A New Self-Healing Hydrogel Containing hucMSC-Derived Exosomes Promotes Bone Regeneration.

BackgroundFractures are a medical disease with a high incidence, and about 5–10% of patients need bone transplantation to fill the defect. In this study, we aimed to synthesize a new type of coralline hydroxyapatite (CHA)/silk fibroin (SF)/glycol chitosan (GCS)/difunctionalized polyethylene glycol (DF-PEG) self-healing hydrogel and to evaluate the therapeutic effects of this novel self-healing hydrogel as a human umbilical cord mesenchymal stem cells (hucMSC)-derived exosome carrier on bone defects in SD rat.MethodsHucMSCs were isolated from fetal umbilical cord tissue and characterized by surface antigen analysis and pluripotent differentiation in vitro. The cell supernatant after ultracentrifugation was collected to isolate exosomes, which were characterized by transmission electron microscopy and western blot analysis. In vitro cell induction experiments were performed to observe the effects of hucMSC-derived exosomes on the biological behavior of mouse osteoblast progenitor cells (mOPCs) and human umbilical vein endothelial cells (HUVECs). The CHA/SF/GCS/DF-PEG hydrogels were prepared using DF-PEG as the gel factor and then structural and physical properties were characterized. HucMSCs-derived exosomes were added to the hydrogel and their effects were evaluated in SD rats with induced femoral condyle defect. These effects were analyzed by X-ray and micro-CT imaging and H&E, Masson and immunohistochemistry staining.ResultsHucMSC-derived exosomes can promote osteogenic differentiation of mOPCs and promote the proliferation and migration of HUVECs. The CHA/SF/GCS/DF-PEG hydrogel has a high self-healing capacity, perfect surface morphology and the precipitated CHA crystals have a small size and low crystallinity similar to natural bone minerals. The MTT results showed that the hydrogel was non-toxic and have a good biocompatibility. The in vivo studies have shown that the hydrogel containing exosomes could effectively promote healing of rat bone defect. The histological analysis revealed more new bone tissue and morphogenetic protein 2 (BMP-2) in the hydrogel-exosome group. In addition, the hydrogel-exosome group had the highest microvessel density.ConclusionA self-healing CHA/SF/GCS/DF-PEG hydrogel was successfully prepared. The hydrogel has excellent comprehensive properties and is expected to become a new type of bone graft material. This hydrogel has the effect of promoting bone repair, which is more significant after the addition of hucMSC-derived exosomes.

Artificial bone scaffolds of coral imitation prepared by selective laser sintering

Coralline hydroxyapatite (CHA) has been used in clinical for over 20 years. However, coral is an endanger species and has been banned from mining. In addition, coral artificial bone has slow biodegradation of the defects, hindering the growth of new bone. In order to explore the natural coral artificial bone substitute materials, this work proposed using Selective Laser Sintering (SLS) to fabricate natural calcium carbonate/biopolymer composite imitation coral porous structures, and then the surface of the 3D printing product was transformed into a hydroxyapatite thin layer by hydrothermal conversion reaction. The mechanical properties and porosity were optimized by adjusting the SLS processing parameters including laser power, scanning speed and layer thickness. In the composites with the PLLA of 15 wt%, the SLS processing parameters with the laser power of 15 W, laser scanning speed of 1500 mm/s and single layer thickness of 0.08 mm result in the better mechanical properties. After hydrothermal conversion, the products were confirmed to be a mixture of hydroxyapatite (HA) and calcium carbonate by X-ray diffraction (XRD), Fourier transform infrared spectroscopy (FTIR) and energy dispersive X-ray spectroscopy (EDX). The TGA results revealed that increasing the reaction temperature or prolonging the reaction time can increase the degree of hydrothermal reaction and thus promote the transformation of calcium carbonate into hydroxyapatite. The results of cytotoxicity assay and Life/Dead staining showed that the scaffold is not toxic to L929 cells. This work has the materials system innovation and focuses on the study of the effects of the SLS and hydrothermal processes on the mechanical performance and the degree of hydroxylation. Then, the preparation process of imitation coral artificial bone preparation was optimized. it is concluded that the imitation coral artificial bone is a nontoxic biomaterial; however, further study on its osteogenic capacity should be warranted in the future.

A Clinical Study of Early Intervention with Coralline Hydroxyapatite on Fresh Extraction Sockets.

To clinically, histologically and radiologically evaluate the effects of early intervention on fresh extraction sockets, 30 patients were selected and assigned evenly into group A (blood clot) and group B (coralline hydroxyapatite). All participants underwent clinical examination. Oral plaster casts and panoramic radiographs were undertaken before tooth extraction and at 3-4 months after socket grafting. A 6-8 mm sample of longitudinal bone core was obtained using a 2 mm diameter trephine 3-4 month's post-operatively. Group A had a greater decrease in interdental papilla height, which was about 2-3 times more than that of group B (P >0.001). The buccal-lingual alveolar ridge width also absorbed more in group A (P >0.001). Radiological findings were similar. Group B had less new bone formation (P >0.001), and the residual rate was a little high. There was no statistical difference between the two groups in terms of new bone formation rating grade. Clinical, histological and radiological tissue differences were observed between sockets with and without biomaterial grafts 3-4 months after surgery. This indicates that early intervention of extraction sockets is clinically advantageous.

Mandibular Augmentation With a New Sandwich Osteotomy: A Morphologic Study.

Facial asymmetry is one of common complaints in plastic and craniofacial surgery in Orient. Hemimandibular dysplasia has considered to be the key role in facial asymmetry. Despite of the undergrow of mandibular length and height, the lackness of mandibular thickness contributes to the asymmetry. The aim of this study was to describe the therapeutic efficiency of mandibular augmentation with a new sandwich osteotomy with interpositional natural coral and coralline hydroxyapatite (CHA). Nine goats were randomly divided into 3 groups and observed at 6, 12, and 18 months after surgery. All goats received splitting of bilateral mandibular outer cortex and interpositional grafting with natural coral and CHA, respectively (sandwich osteotomy). Data were evaluated and statistically analyzed by t-test. All goats were observed at 3 different time points. The computed tomography images show that the area of operation was healed and the thickness of the mandible was increased in 3 time points. In the 3 groups, mandibular thickness and volume were significantly different compared with those before operation (P < 0.05). The volume of CHA group improved better than coral group (P < 0.05). This study provides a promising alternative method for mandibular augmentation with a sandwich osteotomy and interpositional grafting with natural coral and CHA. The thickness and volume of mandible had been effectively increased in follow-ups.

Mechanical testing of antimicrobial biocomposite coating on metallic medical implants as drug delivery system.

Post-operative infection often occurs following orthopedic and dental implant placement requiring systemically administered antibiotics. However, this does not provide long-term protection. Over the last few decades, alternative methods involving slow drug delivery systems based on biodegradable poly-lactic acid and antibiotic loaded hydroxyapatite microspheres were developed to prevent post-operative infection. In this study, thermally anodised and untreated Ti6Al4V discs were coated with Poly-Lactic Acid (PLA) containing Gentamicin (Gm) antibiotic-loaded coralline Hydroxyapatite (HAp) are investigated. Following chemical characterization, mechanical properties of the coated samples were measured using nanoindentation and scratch tests to determine the elastic modulus, hardness and bonding adhesion between film and substrate. It was found that PLA biocomposite multilayered films were around 400nm thick and the influence and effect of the substrate were clearly observed during the nanoindentation studies with heavier loads. Scratch tests of PLA coated samples conducted at ~160nm depth showed the minimal difference in the measured friction between Gm and non Gm containing films. It is also observed that the hardness values of PLA film coated anodised samples ranged from 0.45 to 1.9GPa (dependent on the applied loads) against untreated coated samples which ranged from 0.28 to 0.8GPa.

Construction of vascularized tissue-engineered bone with polylysine-modified coral hydroxyapatite and a double cell-sheet complex to repair a large radius bone defect in rabbits

In this study, the potential of vascularized tissue-engineered bone constructed by a double cell-sheet (DCS) complex and polylysine (PLL)-modified coralline hydroxyapatite (CHA) to repair large radius bone defects was investigated in rabbits. Firstly, the DCS complex was obtained after rabbit adipose-derived mesenchymal stem cell (ADSC) culture was induced. Secondly, PLL-CHA composite scaffolds with different concentrations of PLL were prepared by the soaking and vacuum freeze-drying methods, and then the scaffolds were characterized by X-ray diffraction (XRD), Fourier transform infrared (FTIR) spectroscopy, compression performance testing and cytocompatibility evaluation. Thirdly, DCS-PLL-CHA vascularized tissue-engineered bone was constructed in vitro and transplanted into a large radius bone defect model in rabbits. Finally, the potential of the DCS-PLL-CHA vascularized tissue-engineered bone to repair the large bone defect was evaluated through general observations, laser speckle imaging, scanning electron microscopy (SEM), histological staining, radiography observations and RT-PCR. The in vitro experimental results showed that the DCS complex provided a very large cell reserve, which carried a large number of osteoblasts and vascular endothelial cells that were induced in vitro. When the DCS complex was combined with the PLL-CHA scaffold in vitro, the effects of PLL on cell adhesion, proliferation and differentiation led to a situation similar to the chemotaxis of the body, making the combined complex more conducive to graft cellularization than the DCS complex alone. The in vivo experiments showed blood supply on the surface of the callus in each group, and the amount of blood perfusion on the surface of the defect area was almost equal among the groups. At 12 weeks, the surface of the DCS-PLL-CHA group was completely wrapped by bone tissue and osteoids, the cortical bone image was basically continuous, and the medullary cavity was mainly perforated. A large amount of well-arranged lamellar bone was formed, a small amount of undegraded CHA exhibited a linear pattern, and a large amount of bone filling could be seen in the pores. At 12 weeks, the expression levels of BGLAP, SPP1 and VEGF were similar in each group, but PECAM1 expression was higher in the DCS-PLL-CHA group than in the autogenous bone group and CHA group. The results showed that PLL could effectively promote the adhesion, proliferation and differentiation of ADSCs and that DCS-PLL-CHA vascularized tissue-engineered bone has potential for bone regeneration and bone reconstruction and can be used to repair large bone defects. Statement of Significance1. PLL-CHA composite scaffolds with different concentrations of PLL were prepared by the soaking and vacuum freeze-drying methods.2. The vascularized tissue-engineered bone was constructed by the double cell sheet (DCS) complex combined with PLL-CHA scaffolds.3. The DCS-PLL-CHA vascularized tissue-engineered bone has potential for bone regeneration and bone reconstruction and can be used to repair large bone defects.

A Step-by-Step Procedure for Bone Regeneration Using Calcium Phosphate Scaffolds: From Site Preparation to Graft Placement.

Hydroxyapatite (HA) is the main mineral component of bone and teeth. HA is often used as a bone substitute and especially in its granular form it is osteoconductive and osseointegrating as shown by many investigations in animals and humans. HA granules are used for filling bone defects, but they have poor handling qualities and retention at the surgical site, leading to graft voids between the granules and bone tissue and resulting in mechanical instability. Furthermore HA implantation is not constantly followed by favorable results, especially when it is carried out for augmentation of the alveolar ridge. This article offers a protocol for bone reconstruction and predictable implant treatment outcomes. We provide a step-by-step description of both the recipient site and composite graft preparations using coralline HA granules (CHAG) and homologous fibrin glue (HFG). In the present study, 20 randomly selected patients (12 women and 8 men) underwent bone regeneration using CHAG-HFG before a dental implant procedure. Radiographic imaging, physical examination, and histological analysis were performed during a 2-year period. Biopsies were obtained at second-stage surgery before implant insertion using a 2.8-mm trephine bur. A morphological study of 20 bioptic human specimens was performed. Our results demonstrate that this surgical protocol for the preparation of the recipient site associated with a mixture of coralline HA granules with homologous fibrin glue provides reliable bone regeneration, thus reducing failures and minimizing risks of postoperative morbidity.

Enhanced biocompatibility and improved osteogenesis of coralline hydroxyapatite modified by bone morphogenetic protein 2 incorporated into a biomimetic coating

Objectives(1) To determine whether the biocompatibility of coralline hydroxyapatite (CHA) granules could be improved by using an octacalcium phosphate (OCP) coating layer, and/or functionalized with bone morphogenetic protein 2 (BMP-2), and (2) to investigate if BMP-2 incorporated into this coating is able to enhance its osteoinductive efficiency, in comparison to its surface-adsorbed delivery mode. MethodsCHA granules (0.25 g per sample) bearing a coating-incorporated depot of BMP-2 (20 μg/sample) together with the controls (CHA bearing an adsorbed depot of BMP-2; CHA granules with an OCP coating without BMP-2; pure CHA granules) were implanted subcutaneously in rats (n = 6 animals per group). Five weeks later, the implants were retrieved for histomorphometric analysis to quantify the volume of newly generated bone, bone marrow, fibrous tissue and foreign body giant cells (FBGCs). The osteoinductive efficiency of BMP-2 and the rates of CHA degradation were also determined. ResultsThe group with an OCP coating-incorporated depot of BMP-2 showed the highest volume and quality or bone, and the highest osteoinductive efficacy. OCP coating was able to reduce inflammatory responses (improve biocompatibility), and also simple adsorption of BMP-2 to CHA achieved this. ConclusionsThe biocompatibility of CHA granules (reduction of inflammation) was significantly improved by coating with a layer of OCP. Pure surface adsorption of BMP-2 to CHA also reduced inflammation. Incorporation of BMP-2 into the OCP coatings was associated with the highest volume and quality of bone, and the highest biocompatibility degree of the CHA granules. Clinical significanceHigher osteoinductivity and improved biocompatibility of CHA can be obtained when a layer of BMP-2 functionalized OCP is deposited on the surfaces of CHA granules.

Ultrasound evaluation in recombinant human bonemorphogenic protein-2(rhBMP-2) artificial bone angiogenesis

Objective To evaluate the application value of ultrasound in vascularization of different artificial bones. Methods A total of 15 New Zealand rabbits were utilized for model establishment of classic segmental bone defect in bilateral radius. Recombinant human bonemorphogenic protein-2(rhBMP-2) coralline hydroxyapatite(CHA) and CHA were implanted into left and right limbs. Each CHA was divided into 4 equal parts which were examined with conventional ultrasonography and contrast-enhanced ultrasonography(CEUS) on 3 d, 7 d, 11 d, 15 d, 30 d and 45 d respectively. CEUS quantitative was performed by time-intensity curve(TIC), which parameters including the basic intensity(BI), peak intensity (PI), increased signal intensity (ΔSI) and time to peak (TTP). Then the results were analyzed and compared to pathology. Results Within the same duration, the vascularization degree in rhBMP-2 group was stronger than that in the ordinary group with advanced vascularization time. Positive correlation was detected between ΔSI and time of both groups (r=0.938, 0.890; P=0.000), and negative correlation was found between BI/PI or TTP and time (BI/PI: r=-0.798, -0.899; P=0.000; TTP=r-0.874, -0.868; P=0.000). No statistical significance was observed among four observation points of both CHA, which indicated no obvious difference in vascularization degree of each observation point. Conclusions The structure of bone graft can be clearly displayed by conventional ultrasound, and CEUS is able to show the early blood perfusion in two CHA grafts and to accurately evaluate the difference of CHA microvascular growth before and after rhBMP-2 application. The combination of these two techniques is a promising approach of evaluating bone graft vascularization in clinical practice. Key words: Ultrasonography; Bone transplantation; RhBMP-2; Coralline hydroxyapatite; Vascularization

Osteogenesis of dextran sulfate/recombinant human bone morphogenetic protein-2/chitosan nano microspheres combined with coralline hydroxyapatite in repair of large segmental bone defects

Objective To investigate the osteogenic ability of dextran sulfate/recombinant human bone morphogenetic protein-2/chitosan (DS/rhBMP2/CS) nano microspheres combined with coralline hydroxyapatite (CHA) in repair of segmental bone defects. Methods DS/rhBMP2/CS microspheres prepared by ionic crosslinking method were adsorbed into CHA by lyophilization. Seventy-two New Zealand rabbits were randomly divided into 3 equal groups after they had been made into models of bone defect at the right radius. The defects in the 3 groups were implanted respectively with CHA, rhBMP2/CHA and DS/rhBMP2/CS/CHA. Another 18 animals served as a blank control group. Blood and bone samples were obtained at 4, 8 and 12 weeks after implantation. The serum BGP was detected, and the bone grafts were scanned by micro-CT for calculation of volume ratio of the new bone. Hematoxylin and eosin (HE) staining was performed after bonedecalcification. Results All the 72 animals recovered well without any infection or graft exposure. Gross observation at postoperative 12 weeks showed that the DS/rhBMP2/CS/CHA group was the best in the quality, quantity and strength of the new bone, as well as in the healing of bone defects. The serum levels of bone gamma-carboxyglutamic-acid-containing protein at all time points in the DS/rhBMP2/CS/CHA group were significantly higher than those in the CHA and rhBMP2/CHA groups (P<0.05). Micro-CT scanning demonstrated obvious progress in bone formation, cortical bone and marrow cavity at all time points in the DS/rhBMP2/CS/CHA group which showed significantly faster bone reconstruction synchronized with material degradation and significantly higher volume ratio of the new bone than the other 2 groups (P<0.05). Histological examinations showed better morphology of mature cortical bone and new marrow cavity at all time points in the DS/rhBMP2/CS/CHA group than in the other 2 groups. Conclusion Since DS/rhBMP2/CS/CHA possesses a better mechanism of sustained-releasing rhBMP2 to induce bone formation because of its reticular and hole-hole-connected structure, it may perform better in repairing segmental bone defects than simple CHA or rhBMP2/CHA. Key words: Chitosan; Hydroxyapatite; Glucans; Recombinant human morphogenetic protein-2; Bone defect

Radiological evaluation of dextran sulfate/recombinant human bone morphogenetic protein 2/chitosan composite microspheres combined with coral hydroxyapatite artificial bone in repairing large segmental bone defects

To evaluate the osteogenic effect of dextran sulfate/recombinant human bone morphogenetic protein 2/chitosan (DS/rhBMP-2/CS) combined with coralline hydroxyapatite (CHA) in repairing large segmental bone defects by radiographic feature. Fifty-seven 24-week-old male New Zealand rabbits were prepared for establishing right radius bone defect model of 20 mm in length. In which 54 rabbits were randomly divided into 3 groups ( n=18), and the CHA, DS/rhBMP-2/CS/CHA, and rhBMP-2/CHA artificial bone grafts were implanted into the bone defect in groups A, B, and C respectively; the remaining 3 rabbits were implanted nothing as blank control group. After operation, the gross condition of the animals was observed; at 4, 8, and 12 weeks after operation, X-ray film observation, Micro-CT scanning, and three-dimensional reconstruction were performed to obtain the volume of the new bone. The experimental animals recovered well and were in normal condition. X-ray observation showed that the bone healing in group B was better than that in groups A and C at each time point. At each time point after operation, the X-ray scores of group B were significantly higher than that of group A and group C ( P<0.05); the scores of group C at 8 and 12 weeks after operation were significantly higher than that of group B ( P<0.05). Micro-CT scanning and three-dimensional reconstruction observation showed that at each time point after operation in group A, the bone defect area had less bone formation and poor osteogenesis; in group B, there were many new bone tissues in bone defect area, and the bone remodeling was well, and gradually closed to normal bone morphology at 12 weeks; in group C, there were many new bone tissues in bone defect area, but the bone formation was general. The new bone volume of group B was significantly higher than that of group A and group C ( P<0.05) at each time point after operation, and the score of group C was higher than that of group A at 8 weeks after operation ( P<0.05). The osteogenic effect of DS/rhBMP-2/CS/CHA sustained-release artificial bone is much better than that of single CHA and rhBMP-2/CHA, which can provide a new idea for treating bone defect by using bone tissue engineering in the future.

Antibiotic Containing Poly Lactic Acid/Hydroxyapatite Biocomposite Coatings for Dental Implant Applications

The biodegradable and biocompatible antibiotic containing thin film composites are very appropriate biomaterials as coating materials for dental implants because of their adjustable drug loading and release rates for the prevention of implant related infections. Coralline hydroxyapatite (HAp) was loaded with gentamicin antibiotics and combined with a biodegradable polylactic acid (PLA) to form thin film composites. PLA-HAp, PLA-Gentamicin (GM) and PLA-HAp-GM composites were produced, and their dissolution studies were carried out in phosphate buffered saline under SINK conditions. It was observed that the coatings could be efficiently applied to titanium dental implants and the drug release rates can be efficiently controlled.

The healing of alveolar bone defects with novel bio-implants composed of Ad-BMP9-transfected rDFCs and CHA scaffolds

Cells, scaffolds, and growth factors play important roles in bone regeneration. Bone morphogenetic protein 9 (BMP9), a member of BMP family, could facilitate osteogenesis by regulating growth factors and promoting angiogenesis. Similar to other stem cells, rat dental follicle stem cells (rDFCs), the precursor cells of cementoblasts, osteoblasts and periodontal ligament cells, can self-renew and exhibit multipotential capacity. Coralline hydroxyapatite (CHA) has good biocompatibility and conductivity required for bone tissue engineering. Here, we reported that BMP9 could enhance the osteogenic differentiation of rDFCs in cell culture. Moreover, our results suggested that BMP9 acted through the Smad1/5/8 signaling pathway. We also produced a novel scaffold that encompasses bio-degradable CHA seeded with recombinant adenoviruses expressing BMP9-transfected rDFCs (Ad-BMP9-transfected rDFCs). With this implant, we achieved more alveolar bone regeneration in the alveolar bone defect compared to blank group, CHA group and rDFCs group. Our results provided a novel bio-implants composed of Ad-BMP9-transfected rDFCs and CHA scaffolds and its mechanism is regarding the activation of Smad1/5/8 signaling pathway in BMP9-induced rDFCs osteogenesis.

Clinical Application of Ceramics in Anterior Cervical Discectomy and Fusion: A Review and Update.

Study Design:Narrative review.Objectives:Anterior cervical discectomy and fusion (ACDF) is a reliable procedure, commonly used for cervical degenerative disc disease. For interbody fusions, autograft was the gold standard for decades; however, limited availability and donor site morbidities have led to a constant search for new materials. Clinically, it has been shown that calcium phosphate ceramics, including hydroxyapatite (HA) and tricalcium phosphate (TCP), are effective as osteoconductive materials and bone grafts. In this review, we present the current findings regarding the use of ceramics in ACDF.Methods:A review of the relevant literature examining the clinical use of ceramics in anterior cervical discectomy and fusion procedures was conducted using PubMed, OVID and Cochrane.Result:HA, coralline HA, sandwiched HA, TCP, and biphasic calcium phosphate ceramics were used in combination with osteoinductive materials such as bone marrow aspirate and various cages composed of poly-ether-ether-ketone (PEEK), fiber carbon, and titanium. Stand-alone ceramic spacers have been associated with fracture and cracks. Metallic cages such as titanium endure the risk of subsidence and migration. PEEK cages in combination with ceramics were shown to be a suitable substitute for autograft.Conclusion:None of the discussed options has demonstrated clear superiority over others, although direct comparisons are often difficult due to discrepancies in data collection and study methodologies. Future randomized clinical trials are warranted before definitive conclusions can be drawn.