Autotransplantation of Teeth and the Reconstruction of Alveolar Bone Defects Using Artificial Bone: A Case Series

The aim of this study was to evaluate the outcome of autotransplantation or replantation of extracted teeth combining with reconstruction of alveolar bone defects in use of artificial bone grafting clinically and radiographically. This article presents a more useful and convenient method for repairing tooth and reconstruction of bone defecting with some interesting cases. Eleven patients (seven men and four women) in whom teeth with complete root formation were extracted and autotransplanted, the bone of receiving area was Insufficient. All transplanted teeth were stabilized with orthodontic wire and resin or 4-0 silk sutures;at the same time, artificial bone powder was filled. In 11 cases, the missing teeth were restored by autogenous teeth and the alveolar bone defect was restored by artificial bone, the improvement in the radiographic and clinical parameters strongly suggest that it may be a useful therapy to solve the problem of the missing teeth and alveolar bone insufficiency simultaneously. However, the risk of replacement root resorption remains.

ROLE OF TRANSFORMING GROWTH FACTOR β(TGF-β)IN REPAIRING OF BONE DEFECTS

TGF-β is a multifunctional cytokine that regulates many aspects of cellular function, including periosteal mesenchymal cell proliferation, differentiation. This experiment is to study its effects on bone defect repair. A rabbit radial bone defect model was used to evaluate the effect of TGF-β, which was extracted and purified from bovine blood platelets, on the healing of a large segmental osteoperiosteal defect. A 1. 5-centimeter segmental defect was created in the mid-upper part of the radial shaft of adult rabbits. The defect was filled with implant containing TGF-β that consisted of carrier and bovine TGF-β. Limbs served as controls received carrier alone. The defectswere examined radiographically and histologically at 4, 8,12 , 16 and 20 weeks after implantation. The results showed that in TGF-β implant group . the defect areas at 12 weeks post operation were bridged by uniform new bone and the cut ends of cortex could not be seen;while in control group, the defects remained clear. Only a small amount of new bone formed as a cap on the cut bone ends. In the experimental group, new lamellar and woven bone formed in continuity with the cut ends of the cortex. An early medullar canal appears to be forming and contained normal-appearancing marrow elements; while the control group displayed entirely fibrous tissue within the defect site. Remnants of the cancellous bone carrier were observed in the control specimen. These data demonstrate that exogenous TGF-β initiate osteogenesis and stimulate the bone defects repair in animal model.

Bone Regeneration Enhanced by Antigen-Extracted Xenogeneic Cancellous Bone Graft with rhBMP-2 in Rabbits Mandibular Defect Repair

The effects of large piece xenogeneic bone which was separated from healthy pigs as a scaffold on repair of mandibular defect was investigated and the applicability of antigen-extracted xenogeneic cancellous bone (AXCB) soaked with rhBMP-2 in bone defect repair was assessed. Mandibular defects were created in 48 New Zealand Rabbits, and then randomly divided into 4 groups, which was grafted in the mandibular defects with AXCB, AXCB soaked with rhBMP-2, autograft bone, or blank. Equal number of animals from each group was classified into three time points (4, 8, and 12 weeks) after operation for gross pathological observation, hematoxylin and eosin (H & E) staining, radiographic examination, and bone density measurement. H & E staining revealed that the area percentage of bone regeneration in the group of AXCB/rhBMP-2 graft was 27.72 ± 4.68, 53.90 ± 21.92, and 77.35 ± 9.83 when at 4, 8, and 12 weeks, which was better than that of auto bone graft, prompting that the group of AXCB/rhBMP-2 graft had commendable osteogenic effect. And comparing with the AXCB without rhBMP-2, of which the area percentage of bone regeneration was only 14.03 ± 5.02, 28.49 ± 11.35, and 53.90 ± 21.92, the osteogenic effect of AXCB/rhBMP-2 graft was demonstrated to be much better. In the group of AXCB/rhBMP-2 graft, the area percentage of bone regeneration increased, and the implanted materials were gradually degraded and replaced by autogenous bone regeneration over time. We concluded that antigen-extracted xenogeneic cancellous bone (AXCB) graft soaked with rhBMP-2 had shown excellent osteogenic effect in repair of bone defects, with good biocompability.

Biodegradable materials for bone defect repair

Compared with non-degradable materials,biodegradable biomaterials play an increasingly important role in the repairing of severe bone defects,and have attracted extensive attention from researchers.In the treatment of bone defects,scaffolds made of biodegradable materials can provide a crawling bridge for new bone tissue in the gap and a platform for cells and growth factors to play a physiological role,which will eventually be degraded and absorbed in the body and be replaced by the new bone tissue.Traditional biodegradable materials include polymers,ceramics and metals,which have been used in bone defect repairing for many years.Although these materials have more or fewer shortcomings,they are still the cornerstone of our development of a new generation of degradable materials.With the rapid development of modern science and technology,in the 21 st century,more and more kinds of new biodegradable materials emerge in endlessly,such as new intelligent micro-nano materials and cell-based products.At the same time,there are many new fabrication technologies of improving biodegradable materials,such as modular fabrication,3 D and 4 D printing,interface reinforcement and nanotechnology.This review will introduce various kinds of biodegradable materials commonly used in bone defect repairing,especially the newly emerging materials and their fabrication technology in recent years,and look forward to the future research direction,hoping to provide researchers in the field with some inspiration and reference.

One-Stage Repair and Reconstruction of Craniomaxillofacial Bone Defects

Objective: Severe craniomaxillofacial injuries and craniomaxillofacial tumors can lead to craniomaxillofacial bone defects and deformities. Seriously affect the patients’ appearance and quality of life. So one-stage repair and reconstruction of craniomaxillofacial bone defects is of great significance. The current study summarizes the clinical experience of one-stage repair and reconstruction of craniomaxillofacial bone defects. Material and Methods: Data in one-stage repair and reconstruction of?craniomaxillofacial bone defects performed on 13 patients were retrospectively analyzed out of 34 patients with?craniomaxillofacial injuries or tumors who received treatment at the outpatient department between January 2002 and March 2011. Surgical indications and approaches were explored after two typical cases were detected. Results: One-stage repair and reconstruction of bone defects was suitable for patients with craniomaxillofacial injuries and excised craniomaxillofacial benign tumors. Adjacent autogenous bones and artificial materials (such as titanium plates, titanium mesh, and so on) work well for the repair of the craniomaxillofacial bone frame and restoration of facial features. Conclusions: Surgical indications should be strictly selected in one-stage repair and reconstruction of craniomaxillofacial bone defects and deformities. Furthermore, the adoption of autogenous bones and artificial materials is a good choice in restoring the craniofacial features.

Role of transforming growth factor P and bone morphogenetic protein composite on repair of bone defects

Objective: To study the effect of transforming growth factor β/bone morphogenetic protein (TGFβ/BMP) composite on healing of large segmental bone defects and the interaction between TGF-β and BMP.Methods: A 1. 5-centimeter segmental defect was created in the mid-upper part of the radial shaft of adultrabbit. The defects were filled with implant of TGF-β/carrier, BMP/carrier and TGF-a/BMP/carrier, respectively. Purified bovine TGF-β 120 μg and BMP 12 mg were used in the composite. The defects were examined radiographically and histologically at 4, 8. 12 and 16 weeks post-operation (PO). Results: In groupof TGF-β/carrier, the defect areas were bridged at 4 weeks PO, with material of uniform radiodensity. Conices of the cut ends were obscured by the new bone. By 16 weeks PO, the defects were bridged by uniformnew bone and the cut ends of cortex could not be seen in all groups. In group of BMP/carrier, the defectswere filled with more irregular woven callus in comparison with the other two groups. The TGF-β/BMP--implanted defect sites in animals killed at 16 weeks PO showed histologically new larnellar and woven bone,formed in continuity with the cut ends of the cortex. The medullar cavity was recanalized and contained marrow elements with normal appearance. ConClUsion: These data demonstrate the synergistic action betweenTGF-β and BMP in the process of bone healing, and the better effect of TGF-β/BMP composite than that ofsingle TGF-β or BMP on bone repair.

Effect of low intensity pulsed ultrasound on repairing the periodontal bone of Beagle canines

Objective:To investigate the repairing effect of low intensity pulsed ultrasound(LIPUS)on the Beagle canines periodontal bone defect.Methods:A total of 12 Beagle dogs with periodontal bone defect model were randomly divided into control group,LIPUS group,guided tissue regeneration(GTR)group and LIPUS+GTR group,with three in each.After completion of the models,no other proceeding was performed in control group;LIPUS group adopt direct exposure to radiation line LIPUS processing 1 week after modeling;GTR group adopted treatment with GTR,following the CTR standard operation reference;LIPUS+GTR group was treated with LIPUS joint GTR.Temperature change before treatment and histopathological change of periodontal tissue after repair was observed.Results:There was no significant difference in temperature changes of periodontal tissue between groups(P>0.05).The amount and maturity of LIPUS+GTR group were superior to other groups;new cementum,dental periodontal bones of GTR group were superior to the control group but less than LIPUS group;new collagen and maturity of the control group is not high relatively.Conclusions:LIPUS can accelerate the calcium salt deposition and new bone maturation,thus it can serve as promoting periodontal tissue repair,and shortening the periodontal tissue repair time.

Structural bone allografts with intramedullary vascularized fibular autografts for the treatment of massive bone defects in extremities

Objective:To report the clinical outcome of repairing massive bone defects biologically in limbs by homeochronous using structural bone allografts with intramedullary vascularized fibular autografts. Methods: From January 2001 to December 2005, large bone defects in 19 patients (11 men and 8 women, aged 6 to 35 years) were repaired by structural bone allografts with intramedullary vascularized fibular autografts in the homeochronous period. The range of the length of bone defects was 11 to 25 cm (mean 17.6 cm), length of vascularized free fibular was 15 to 29 cm (mean 19.2 cm), length of massive bone allografts was 11 to 24 cm (mean 17.1 cm). Location of massive bone defects was in humerus(n=1), in femur(n=9) and in tibia(n=9), respectively. Results: After 9 to 69 months (mean 38.2 months) follow-up, wounds of donor and recipient sites were healed inⅠstage, monitoring-flaps were alive, eject reaction of massive bone allografts were slight, no complications in donor limbs. Fifteen patients had the evidence of radiographic union 3 to 6 months after surgery, 3 cases united 8 months later, and the remained one case of malignant synovioma in distal femur recurred and amputated the leg 2.5 months, postoperatively. Five patients had been removed internal fixation, complete bone unions were found one year postoperatively. None of massive bone allografts were absorbed or collapsed at last follow-up. Conclusion: The homeochronous usage of structural bone allograft with an intramedullary vascularized fibular autograft can biologically obtain a structure with the immediate mechanical strength of the allograft, a potential result of revascularization through the vascularized fibula, and accelerate bone union not only between fibular autograft and the host but also between massive bone allograft and the host.

Effect of beta-tricalcium phosphate/poly-1-lactide composites on radial bone defects of rabbit

Objective:To explore the effect ofβ-TCP/PLLA scaffold in repairing rabbit radial lone defects.Methods:Thirty New Zealand rabbits were divided intoβ-TCP/PLLA group(group A),pure PLLA group(group B)and contrast group(group C)randomly.The rabbits were sacrificed respectively after 4.8.12,24 weeks and the X-ray film was performed at the same time to evaluate the repair effect in different groups.Retiults:X-ray film showed there was uneven low density bone callus development in defect region after 4 weeks in group A.The defect region was filled with neonate osseous tissue completely during 12-24 weeks.X-ray score revealed that repair of bone defect results significantly better than group B and group C.Conclusions:Theβ-PCP/PLLA composite is capable of repairing radial lone lone defects.β-TCP/PLLA scaffold is significant because of rapid degradation ability,good histocompatihility and osteogenic action.

Preparation and characterization of hemihydrate calcium sulfate-calcium hydroxide composite bone repair materials

Objective:To prepare a bone repair material with certain mechanical strength and biological activity,this paper used calcium sulfate hemihydrate(CSH)powder compounded with calcium hydroxide(Ca(OH)2)powder to prepare a bone repair scaffold material for physicochemical property characterization and testing.Methods:The physical and chemical properties and characterization of the dried and cured bone repair materials were determined by Fourier infrared spectroscopy(FT-IR),X-ray diffraction(XRD),and scanning electron microscopy;Universal material testing machine to determine the mechanical and mechanical strength of composite materials.Results:XRD showed that the structure of the composite material phase at 5%concentration was calcium sulfate hemihydrate and calcium hydroxide after hydration.The FT-IR and XRD analyses were consistent.Scanning electron microscopy(SEM)results showed that calcium hydroxide was uniformly dispersed in the hemihydrate calcium sulfate material.0%,1%,5%,and 10%specimen groups had compressive strengths of 3.86±3.1,5.27±1.28,8.22±0.96,and 14.4±3.28 MPa.10%addition of calcium hydroxide significantly improved the mechanical strength of the composites,but also reduced the the porosity of the material.Conclusion:With the addition of calcium hydroxide,the CSH-Ca(OH)2 composite was improved in terms of mechanical material and is expected to be a new type of bone repair material.

A comparative study of autogenous, allograft and artificial bone substitutes on bone regeneration and immunotoxicity in rat femur defect model

Repair and reconstruction of large bone defect were often difficult,and bone substitute materials,including autogenous bone,allogenic bone and artificial bone,were common treatment strategies.The key to elucidate the clinical effect of these bone repair materials was to study their osteogenic capacity and immunotoxicological compatibility.In this paper,the mechanical properties,micro-CT imaging analysis,digital image analysis and histological slice analysis of the three bone grafts were investigated and compared after different time points of implantation in rat femur defect model.Autogenous bone and biphasic calcium phosphate particular artificial bone containing 61.4% HA and 38.6%β-tricalcium phosphate with 61.64%porosity and 0.8617±0.0068 g/cm^(3) den-sity(d≤2 mm)had similar and strong bone repair ability,but autogenous bone implant materials caused greater secondary damage to experimental animals;allogenic bone exhibited poor bone defect repair ability.At the early stage of implantation,the immunological indexes such as Immunoglobulin G,Immunoglobulin M concentration and CD4 cells'population of allogenic bone significantly increased in compared with those of autologous bone and artificial bone.Although the repair process of artificial bone was relatively inefficient than autologous bone graft,the low immunotoxicological indexes and acceptable therapeutic effects endowed it as an excellent alter-native material to solve the problems with insufficient source and secondary trauma of autogenous bone.

The Clinical Application of Human Bone Matrix Gelatin

This paper reports the results of 24 cases of bone defect resulting from bone tumor or tumor condition excision, and of posterior spinal fusion, treated by human bone matrix gelatin. The success rate of bone defect repair and spinal fusion is 91. 67 %. The results suggest that human bone matrix gelatin has. excellent osteoinductive effect and is ideal substitute for bone autografts.

Artificial periosteum in bone defect repair--A review

Periosteum is a thin membrane that encases the surfaces of most bones.It is composed of an outer fibrous layer contains longitudinally oriented cells and collagen fibers and an inner cambial layer that consists of multipotent mesenchymal stem cells（MSCs）and osteogenic progenitor cells.Periosteum has a function of regulating cell and collagen arrangement,which is important to the integrity,modelling and remodelling of bone,particularly during bone defect repair.Apart from autograft and allograft,artificial periosteum,or tissue-engineered periosteum mimicking native periosteum in structure or function,made up of small intestinal submucosa,acellular dermis,induced membrane,cell sheets,and polymeric scaffolds,and so on,has been developed to be used in bone defect repair.In this review,we classify the artificial periosteum into three approaches based on the material source,that is,native tissues,scaffoldfree cell sheets and scaffold-cell composites.Mechanisms,methods and efficacy of each approach are provided.Existing obstacles and enabling technologies for future directions are also discussed.

Repair of sciatic nerve defects using tissue engineered nerves

In this study, we constructed tissue-engineered nerves with acellular nerve allografts in Sprague-Dawley rats, which were prepared using chemical detergents-enzymatic digestion and mechanical methods, in combination with bone marrow mesenchymal stem cells of Wistar rats cultured in vitro, to repair 15 mm sciatic bone defects in Wistar rats. At postoperative 12 weeks, electrophysiological detection results showed that the conduction velocity of regenerated nerve after repair with tissue-engineered nerves was similar to that after autologous nerve grafting, and was higher than that after repair with acellular nerve allografts. Immunohistochemical staining revealed that motor endplates with acetylcholinesterase-positive nerve fibers were orderly arranged in the middle and superior parts of the gastrocnemius muscle; regenerated nerve tracts and sprouted branches were connected with motor endplates, as shown by acetylcholinesterase histochemistry combined with silver staining. The wet weight ratio of the tibialis anterior muscle at the affected contralateral hind limb was similar to the sciatic nerve after repair with autologous nerve grafts, and higher than that after repair with acellular nerve allografts. The hind limb motor function at the affected side was significantly improved, indicating that acellular nerve allografts combined with bone marrow mesenchymal stem cell bridging could promote functional recovery of rats with sciatic nerve defects.

Dual-response of multi-functional microsphere system to ultrasound and microenvironment for enhanced bone defect treatment

Using bone tissue engineering strategies to achieve bone defect repair is a promising modality.However,the repair process outcomes are often unsatisfactory.Here we properly designed a multi-functional microsphere system,which could deliver bioactive proteins under the dual response of ultrasound and microenvironment,release microenvironment-responsive products on demand,reverse bone injury microenvironment,regulate the immune microenvironment,and achieve excellent bone defect treatment outcomes.In particular,the MnO_(2) introduced into the poly(lactic-co-glycolic acid)(PLGA)microspheres during synthesis could consume the acid produced by the degradation of PLGA to protect bone morphogenetic protein-2(BMP-2).More importantly,MnO_(2) could consume reactive oxygen species(ROS)and produce Mn^(2+)and oxygen(O_(2)),further promoting the repair of bone defects while reversing the microenvironment.Moreover,the reversal of the bone injury microenvironment and the depletion of ROS promoted the polarization of M1 macrophages to M2 macrophages,and the immune microenvironment was regulated.Notably,the ultrasound(US)irradiation used during treatment also allowed the on-demand release of microenvironment-responsive products.The multi-functional microsphere system combines the effects of on-demand delivery,reversal of bone injury microenvironment,and regulation of the immune microenvironment,providing new horizons for the clinical application of protein delivery and bone defect repair.

Guided bone regeneration in long-bone defect with a bilayer mineralized collagen membrane

Bone regeneration for large,critical-sized bone defects remains a clinical challenge nowadays.Guided bone regeneration(GBR)is a promising technique for the repair of multiple bone defects,which is widely used in oral and maxillofacial bone defects but is still unsatisfied in the treatment of long bone defects.Here,we successfully fabricated a bilayer mineralized collagen/collagen(MC/Col)-GBR membrane with excellent osteoinductive and barrier function by coating the MC particles prepared via in situ biomimetic mineralization process on one side of a sheet-like pure collagen layer.The aim of the present study was to investigate the physicochemical properties and biological functions of the MC/Col film,and to further evaluate its bone regeneration efficiency in large bone defect repair.Fouriertransform infrared spectra and X-ray diffraction patterns confirmed the presence of both hydroxyapatite and collagen phase in the MC/Col film,as well as the chemical interaction between them.stereo microscope,scanning electron microscopy and atomic force microscope showed the uniform distribution of MC particles in the MC/Col film,resulting in a rougher surface compared to the pure Col film.The quantitative analysis of surface contact angle,light transmittance and tensile strength demonstrated that the MC/Col film have better hydrophilicity,mechanical properties,light-barrier properties,respectively.In vitro macrophage co-culture experiments showed that the MC/Col film can effectively inhibit macrophage proliferation and fusion,reducing fibrous capsule formation.In vivo bone repair assessment of a rabbit critical segmental radial defect proved that the MC/Col film performed better than other groups in promoting bone repair and regeneration due to their unique dual osteoinductive/barrier function.These findings provided evidence that MC/Col film has a great clinical potential for effective bone defect repair.

Methacrylated gelatin and platelet-rich plasma based hydrogels promote regeneration of critical-sized bone defects

Physiological repair of large-sized bone defects requires instructive scaffolds with appropriate mechanical properties,biocompatibility,biodegradability,vasculogenic ability and osteo-inductivity.The objective of this study was to fabricate in situ injectable hydrogels using platelet-rich plasma(PRP)-loaded gelatin methacrylate(GM)and employ them for the regeneration of large-sized bone defects.We performed various biological assays as well as assessed the mechanical properties of GM@PRP hydrogels alongside evaluating the release kinetics of growth factors(GFs)from hydrogels.The GM@PRP hydrogels manifested sufficient mechanical properties to support the filling of the tissue defects.For biofunction assay,the GM@PRP hydrogels significantly improved cell migration and angiogenesis.Especially,transcriptome RNA sequencing of human umbilical vein endothelial cells and bone marrow-derived stem cells were performed to delineate vascularization and biomineralization abilities of GM@PRP hydrogels.The GM@PRP hydrogels were subcutaneously implanted in rats for up to 4 weeks for preliminary biocompatibility followed by their transplantation into a tibial defect model for up to 8 weeks in rats.Tibial defects treated with GM@PRP hydrogels manifested significant bone regeneration as well as angiogenesis,biomineralization,and collagen deposition.Based on the biocompatibility and biological function of GM@PRP hydrogels,a new strategy is provided for the regenerative repair of large-size bone defects.

Transfect bone marrow stromal cells with pcDNA3.1-VEGF to construct tissue engineered bone in defect repair

Background We previously showed that nano-hydroxyapatite/carboxymethyl chitosan （n-Ha/CMCS） displayed excellent mechanical properties, good degradation rates and exceptional biocompatibility, with negligible toxicity. The aim of this study was to determine the effect of the same composite with vascular endothelial growth factor （VEGF）transfected bone marrow stromal cells （BMSCs） in a rabbit radial defect model.

Optimal regenerative repair of large segmental bone defect in a goat model with osteoinductive calcium phosphate bioceramic implants

So far,how to achieve the optimal regenerative repair of large load-bearing bone defects using artificial bone grafts is a huge challenge in clinic.In this study,a strategy of combining osteoinductive biphasic calcium phosphate(BCP)bioceramic scaffolds with intramedullary nail fixation for creating stable osteogenic microenvironment was applied to repair large segmental bone defects(3.0 cm in length)in goat femur model.The material characterization results showed that the BCP scaffold had the initial compressive strength of over 2.0 MPa,and total porosity of 84%.The cell culture experiments demonstrated that the scaffold had the excellent ability to promote the proliferation and osteogenic differentiation of rat bone marrow-derived mesenchymal stem cells(BMSCs).The in vivo results showed that the intramedullary nail fixation maintained the initial stability and structural integrity of the implants at early stage,promoting the osteogenic process both guided and induced by the BCP scaffolds.At 9 months postoperatively,good integration between the implants and host bone was observed,and a large amount of newborn bones formed,accompanying with the degradation of the material.At 18 months postoperatively,almost the complete new bone substitution in the defect area was achieved.The maximum bending strength of the repaired bone defects reached to the 100% of normal femur at 18 months post-surgery.Our results demonstrated the good potential of osteoinductive BCP bioceramics in the regenerative repair of large load-bearing bone defects.The current study could provide an effective method to treat the clinical large segmental bone defects.