Hard Tissue Reconstruction Research Articles

Outcomes of Immediate Allograft Reconstruction of Long-Span Defects of the Inferior Alveolar Nerve

Contemporary management of ablative jaw defects includes not only hard and soft tissue reconstruction, but also restoration of neurosensory function. The goal of this study was to determine the outcomes of immediate reconstruction of long-span defects (≥50mm) of the inferior alveolar nerve (IAN) after ablative mandibular resection using allogeneic nerve grafts. A retrospective cohort study of patients who underwent immediate reconstruction of IAN gaps of at least 50mm with allogeneic nerve graft (AxoGen Avance, Alachua, FL) at a single academic medical center by a single surgeon (M.M.) from September 2013 to March 2015 was completed. Demographic and clinical data were collected for each patient and analyzed using clinical neurosensory testing and were reported using the Medical Research Council Scale (MRCS) for functional sensory recovery. In addition, patient subjective perception of neurosensory recovery was recorded using a visual analog scale (VAS). Subjective (VAS) and objective (MRCS) measurements of functional sensory recovery were recorded and compared across the study population. In addition, examined demographic and clinical data included patient age, gender, pathology, length of nerve allograft, and follow-up period. Of 12 with nerve repairs, 7 patients met the inclusion criteria. The average age was 34.7years (range, 18 to 61yr) and 71.4% were men. All IAN defects resulted from resection of mandibular pathology (6 benign lesions, 1 malignant lesion). Six of the 7 IAN defects were reconstructed with a 70-mm nerve allograft, and 1 nerve defect was reconstructed with a 50-mm graft. Mean follow-up time was 17.7months (range, 10 to 27.5months). Mean VAS score reported was 3.7 (range, 0 to 7). In addition, 85.7% of patients displayed return of some superficial pain and tactile sensation without over-response (S3), with 14.3% displaying good stimulation localization (S3+). The patient who displayed S3+ recovery underwent reconstruction with the 50-mm graft. Only 1 of the 7 patients had no neurosensory recovery (S0). Immediate reconstruction of the IAN with allogeneic nerve grafting of long-span defects (≥5cm) is a viable and predictable option to achieve useful functional sensory recovery.

Oral and maxillofacial bone reconstruction

Event Abstract Back to Event Oral and maxillofacial bone reconstruction John Jansen1, Jeroen Van Den Beucken1 and Sander Leeuwenburgh1 1 Radboudumc - Dentistry, Biomaterials, Netherlands Hard tissue reconstruction in the oral and maxillofacial region due to trauma, tumor surgery or congenital deformities remains a challenge for reconstructive surgeons. The current preferred treatment includes the use of vascularized bone grafts, such as pedicle grafts or microvascular free grafts. This even extends to the use of computer-assisted modeling to preoperatively design the tumor resection and contour the microvascular free flap reconstruction by using a customized template. However, the current techniques have inherent disadvantages of donor site morbidity, risk of infection or non-acceptance of the flap as well as a prolonged healing and waiting time before dental rehabilitation can begin. Bone regeneration is a well-organized but complex physiological process, in which different cell types and their activated signaling pathways are involved. In bone regeneration and remodeling processes, mesenchymal stem cells (MSCs) have a crucial role, during which their differentiation is regulated by specific signaling molecules (growth factors/cytokines and hormones) and their activated intracellular networks. Especially the utilization of this molecular machinery seems crucial to consider prior to developing bone substitute materials and cell-based constructs for bone regeneration. Regenerative medicine is using the principles of “”tissue engineering”” and holds the promise for custom-tailored constructs with the potential to regenerate tissue in the host without significant donor-site morbidity and size limitation. This lecture aims to provide an overview of the current possibilities to optimize bone regeneration for cranio-facial reconstruction. First, the function and structure of bone will be discussed as well as the interaction between its main constituents with a specific focus on the mechanisms of bone mineralization. Second, the osteogenic potential of MSCs to become a key cellular resource for such regeneration and remodeling processes and the role of the scaffold material as such or as carrier for biofactors or stem cells will be addressed (Figure 1). Third, attention will be given to the main bio-inspired strategies to mineralize synthetic bone-substituting biomaterials. Figure 1. Cellular concept to explain the osteogenicity of a scaffold surfaces: Step 1: Blood cells penetrate into damaged body tissue (monocytes differentiate into macrophages), Step 2: Blood clot is formed on the scaffold surface (including blood cells and fibrin fibers), Step 3: Platelets and macrophages are activated and secrete growth factors and cytokines, which attract osteoprogenitor cells. The adhesion and activation of platelets and macrophages is controlled by the osteogenicc properties of the used scaffold material. This work was supported by the Dutch Technology Foundation, Smartmix and the Royal Netherlands Academy of Science.; This work is also an AFIRM II project and was supported by the Army, Navy, NIH, Air Force, VA and Health Affairs to support the AFIRM II effort, under Award No. W81XWH-14-2-0004. The U.S.Army Medical Research Acquisition Activity, 820 Chandler Street, Fort Detrick MD 21702-5014 is the awarding and administering acquisition office. Opinions, interpretations and recommendations are those of the author and are not necessarily endorsed by the Department of Defense. Keywords: Bone Regeneration, Regenerative Medicine, Surface modification, bioactive interface Conference: 10th World Biomaterials Congress, Montréal, Canada, 17 May - 22 May, 2016. Presentation Type: New Frontier Oral Topic: Biomaterials in constructing tissue substitutes Citation: Jansen J, Van Den Beucken J and Leeuwenburgh S (2016). Oral and maxillofacial bone reconstruction. Front. Bioeng. Biotechnol. Conference Abstract: 10th World Biomaterials Congress. doi: 10.3389/conf.FBIOE.2016.01.00278 Copyright: The abstracts in this collection have not been subject to any Frontiers peer review or checks, and are not endorsed by Frontiers. They are made available through the Frontiers publishing platform as a service to conference organizers and presenters. The copyright in the individual abstracts is owned by the author of each abstract or his/her employer unless otherwise stated. Each abstract, as well as the collection of abstracts, are published under a Creative Commons CC-BY 4.0 (attribution) licence (https://creativecommons.org/licenses/by/4.0/) and may thus be reproduced, translated, adapted and be the subject of derivative works provided the authors and Frontiers are attributed. For Frontiers’ terms and conditions please see https://www.frontiersin.org/legal/terms-and-conditions. Received: 28 Mar 2016; Published Online: 30 Mar 2016. Login Required This action requires you to be registered with Frontiers and logged in. To register or login click here. Abstract Info Abstract The Authors in Frontiers John Jansen Jeroen Van Den Beucken Sander Leeuwenburgh Google John Jansen Jeroen Van Den Beucken Sander Leeuwenburgh Google Scholar John Jansen Jeroen Van Den Beucken Sander Leeuwenburgh PubMed John Jansen Jeroen Van Den Beucken Sander Leeuwenburgh Related Article in Frontiers Google Scholar PubMed Abstract Close Back to top Javascript is disabled. 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경조직과 연조직의 증강을 통한 상악전치부 임플란트 수복: 증례보고

With the development of treatment of hard and soft tissue around the implants, the implant restoration is increasingly used in the maxillary anterior region which is very important aesthetically. However, the aesthetic reconstruction of the maxillary anterior region is still challenged. Three following conditions should be fully satisfied for aesthetic prosthesis restoration; reconstruction of hard tissue, soft tissue and harmonic prosthesis. In this case report, hard and soft tissue augmentations were performed at atrophied maxillary incisor. Additionally, customized impression coping and provisional restoration were used to make the final restoration.

Fibula Free Flap for Mandibular Reconstruction using Simulation Surgery in Bisphosphonate related Osteonecrosis of the Jaw

Purpose Bisphophonate-related osteonecrosis of the jaw (BRONJ) is an emerging problem. Extensive osteonecrosis of the jaw needs free flap reconstruction. Free fibular flap is the most useful flap for maxilla-mandibular hard and soft tissue reconstruction. The advantages of fibular free flap are simultaneous soft and hard tissue reconstruction and placing implant in reconstructed mandible and maxilla. In this study, four consecutive BRONJ patients who underwent fibula free flap reconstruction using simulation surgery were reviewed. Materials and Methods Four BRONJ patients who underwent free fibula reconstruction between May 2006 and September 2014 were included in this study. Male to female ratio was 1:3 and average age was 67.3 years old (62-70). All patients need mandibular bone reconstruction. Three patients suffered from osteoporosis and one male patient had multiple myeloma. Postoperative flap survival, functional reconstruction, esthetic results, food taking were evaluated. Results Three osseous flaps and one osteocutaneous flap were used. All the fibular flaps were survived and patients were recovered without complications. Oro-cutaneous fistula was resolved after operation. All patients were satisfied with the esthetic results. Patients reported improved solid food intake after operation with partial denture. One fully edentulous patient had semi-fluid diet after operation. Conclusion Treatment of the BRONJ is difficult due to lack of standard protocol. Fibular free flap using simulation surgery is the workhorse flap for mandibular hard and soft tissue reconstruction, especially in stage III BRONJ patient. In this study, functional and esthetic results were successful in all patients. Normal diet was possible with partial dentures.

The regeneration and augmentation of bone with injectable osteogenic cell sheet in a rat critical fracture healing model

Limitations in the current treatment strategies make cases with compromised bone healing challenging clinical problems. Osteogenic cell sheets (OCSs), fabricated from rat bone marrow stromal cells (BMSCs), contain enriched osteoblasts and extracellular matrix. Here, we evaluated whether the minimally invasive percutaneous injection of OCSs without a scaffold could be used as a treatment to increase bone regeneration in a critical fracture healing model. Critical fracture healing model was created in the femora of 60 male Fischer 344 inbred rats using marrow ablation and periosteal removal. The rats were then randomly divided into two groups. Six hours after fracture, one group received an injection of OCSs (OCS group), while the second group was injected with phosphate-buffered saline (PBS) (control group). Fracture healing was evaluated using radiological, histological, micro-computed tomography (CT) and biomechanical analyses. The radiological and histological evaluations demonstrated enhanced bone regeneration in the OCS group compared with that in the control group. By 12 weeks, the hard callus had been remodelled via recorticalization in the OCS group. By contrast, no fracture union was found in the rats in the control group. Biomechanical testing revealed a significantly higher maximum bending load in the OCS group compared with that in the control group. The results of the present study demonstrate that the injection of entire OCSs can enhance bone regeneration and lead to bony union in a critical fracture healing model. Therefore, this procedure offers a minimally invasive technique to promote hard tissue reconstruction and, in particular, bone repair strategies for cases with compromised bone healing.

Response to letter to the editors "Re: Byung-Do Lee, Wan Lee, Kyung-Hwan Kwon, Moon-Ki Choi, Eun-Joo Choi and Jung-Hoon Yoon. Glandular odontogenic cyst mimicking ameloblastoma in a 78-year-old female: a case report. Imaging Science in Dentistry 2014; 44(3): 249-52.".

Response to letter to the editors "Re: Byung-Do Lee, Wan Lee, Kyung-Hwan Kwon, Moon-Ki Choi, Eun-Joo Choi and Jung-Hoon Yoon. Glandular odontogenic cyst mimicking ameloblastoma in a 78-year-old female: a case report. Imaging Science in Dentistry 2014; 44(3): 249-52.".

Utility of tricalcium phosphate and osteogenic matrix cell sheet constructs for bone defect reconstruction

To determine the effects of transplanting osteogenic matrix cell sheets and beta-tricalcium phosphate (TCP) constructs on bone formation in bone defects. Osteogenic matrix cell sheets were prepared from bone marrow stromal cells (BMSCs), and a porous TCP ceramic was used as a scaffold. Three experimental groups were prepared, comprised of TCP scaffolds (1) seeded with BMSCs; (2) wrapped with osteogenic matrix cell sheets; or (3) both. Constructs were implanted into a femoral defect model in rats and bone growth was evaluated by radiography, histology, biochemistry, and mechanical testing after 8 wk. In bone defects, constructs implanted with cell sheets showed callus formation with segmental or continuous bone formation at 8 wk, in contrast to TCP seeded with BMSCs, which resulted in bone non-union. Wrapping TCP constructs with osteogenic matrix cell sheets increased their osteogenic potential and resulting bone formation, compared with conventional bone tissue engineering TCP scaffolds seeded with BMSCs. The compressive stiffness (mean ± SD) values were 225.0 ± 95.7, 30.0 ± 11.5, and 26.3 ± 10.6 MPa for BMSC/TCP/Sheet constructs with continuous bone formation, BMSC/TCP/Sheet constructs with segmental bone formation, and BMSC/TCP constructs, respectively. The compressive stiffness of BMSC/TCP/Sheet constructs with continuous bone formation was significantly higher than those with segmental bone formation and BMSC/TCP constructs. This technique is an improvement over current methods, such as TCP substitution, and is useful for hard tissue reconstruction and inducing earlier bone union in defects.

Bioactive Co-Cr alloy for biomedical applications prepared by surface modification using self-assembled monolayers and poly-γ-glutamic acid.

Cobalt-chromium (Co-Cr) alloys are used in clinical practice for the hard tissue reconstruction because of their favorable biocompatibility and mechanical properties. However, their applications have been limited because of their poor bioactivity, making them poor at bone-bonding. In this study, the bioactivity of a Co-Cr alloy was evaluated following the immobilization of cross-linked poly-γ-glutamic acid (γ-PGA) onto its surface via the formation of 11-aminoundecylphosphonic acid self-assembled monolayers (SAMs). Results of X-ray photoelectron spectroscopy revealed the presence of a new P2p peak, which confirms SAMs formation. Furthermore, the surface became highly hydrophobic following the immobilization with γ-PGA. Subsequent treatment with CaCl2 at 0.5 M or more and soaking in a simulated body fluid led to the formation of a low crystalline apatite. The present results show that chemical modification can be used to induce the formation of an apatite layer on the surface of a Co-Cr alloy in simulated body fluid.

Mechanical properties of artificial materials for bone repair

Bone defect caused by injury, infection, tumor and congenital diseases is one of the most common diseases in clinical orthopaedics. Bone grafts are necessary when self-healing is not effective during the recovery. Preparation of ideal bone substitutes with good biocompatibility and biodegradability to repair bone defects has become the focus. So far artificial materials used in hard tissue repair and reconstruction most notably are metals and their alloys, then the ceramic materials and their composite materials. From the perspective of mechanical properties, metals have some advantages, but corrosion issue and stress shielding of metal have baffled scientists through the age and have been long searched for solution. The elastic modulus of ceramic is more close to the natural bone compared to metal while the improvement of brittleness has been always the emphasis for clinical use. Therefore, development of materials of proper mechanical properties without affecting biological compatibility has become a significant subject.

Carbon nanotube-reinforced hydroxyapatite composite and their interaction with human osteoblast in vitro.

As a bone mineral component, hydroxyapatite (HA) has been an attractive bioceramic for the reconstruction of hard tissues. However, its poor mechanical properties, including low fracture toughness and tensile strength, have been a substantial challenge to the application of HA for the replacement of load-bearing and/or large bone defects. In this study, HA is reinforced with high-purity and well-functionalized multiwalled carbon nanotubes (MWCNTs; >99 wt%) having an average diameter of 15 nm and length from 10 to 20 μm. The cellular response of these functionalized CNTs and its composites were examined in human osteoblast sarcoma cell lines. Calcium nitrate tetrahydrate (Ca(NO3)2·4H2O) and diammonium hydrogen phosphate ((NH4)2HPO4) were used to synthesize HA in situ. MWCNTs were functionalized by heating at 100°C in 3:1 ratio of sulfuric acid and nitric acid for 60 min with stirring and dispersed in sodium dodecyl benzene sulfonate by sonication. HA particles were produced in MWCNTs solution by adding Ca(NO3)2·4H2O and (NH4)2HPO4 under vigorously stirring conditions. The composite was dried and washed in distilled water followed by heat treatment at 250°C to obtain CNT-HA powder. Physiochemical characterization of the composite material was carried out using Fourier transform infrared spectroscopy, field-emission scanning electron microscopy, energy-dispersive X-ray spectrometer, and X-ray diffractometer. Furthermore, this study investigates the cytotoxic effects of functionalized-MWCNTs (f-MWCNTs) and its composites with HA in human osteoblast sarcoma cell lines. Human osteoblast cells were exposed with different concentrations of f-MWCNTs and its composite with HA. The interactions of f-MWCNT and MWCNT-HA composites were analyzed by 3-(4,5-dimethyl thiazol-2-yl)-2,5-diphenyl tetrazolium bromide assay. The results indicate no detrimental effect on survival or mitochondrial activity of the osteoblast cells. Cell viability decreased with an increase in CNT concentration indicating that MWCNTs and its composite can be cytotoxic at higher dosages. This result provides further evidence that the bionano interface can be developed for CNT-reinforced HA composites for load-bearing bone implants, drug delivery, and tissue engineering.

Synthesis and characterization of self-curing hydrophilic bone cements for protein delivery.

New formulations of acrylic bone cements for bone defect reparation, based on self-hardening methyl methacrylate (MMA)/methacrylic acid (MAA), with a high capacity for protein delivery, have been developed. The self-curing formulations were prepared by partial substitution of solid phase PMMA microparticles by newly obtained PMAA microspheres. The PMAA microspheres were prepared by inverse suspension polymerization of their monomer and were cross-linked with N,N'-methylene-bis-acrylamide (MBA) (10-15 wt %) to produce stable systems in contact with aqueous media. PMAA microspheres were loaded with hydrolyzed collagen (HC) as a model protein to simulate bone morphogenetic protein delivery useful for hard tissue reconstruction. Solid phase PMMA microparticles in the formulation were partially substituted by new PMAA-HC microspheres and were characterized to determine viability as an acrylic bone cement in minimally invasive surgery. The incorporation of PMAA-HC microspheres decreased peak temperature by 20°C, which minimized thermal necrotic risk after implantation. Mechanical compression tests revealed a behavior, under dry conditions, close to ISO 5833 standard requirements. However, a drastic drop in mechanical strength, ∼64%, was obtained after 15 days of immersion in simulated physiological conditions (37°C and pH 7.4) and was attributed to water absorption and a subsequent plasticizing effect. The increase in water uptake and retention enhanced the capability for controlled protein delivery. Finally, the biocompatibility of the cements was determined; some toxicity of the material during the first hours of culture incubation was observed. Later, toxicity was observed to decrease due to nonreacted monomer leaching, which ensured the low toxicity of the already polymerized phase.

Interaction of Carbon Nanotubes Reinforced Hydroxyapatite Composite with Bacillus subtilis, P. aeruginosa and C. albicans

Hydroxyapatite (HA), as a bone mineral component, has been an attractive bioceramic for the reconstruction of hard tissues. However, its poor mechanical properties, including low fracture toughness and tensile strength, have been a significant challenge to the application of HA for the replacement of load-bearing and/or large bone defects. Hydroxyapatite (HA) composite is reinforced with high purity and well-functionalized Multiwalled Carbon Naotubes (MWCNT>98 wt%) having an average diameter of 15 nm.The cellular response of f-MWCNT, MWCNT-HA composites were examined to model gram positive and gram negative Bacteria B. subtilis, P. aeruginosa and yeast C. albicans. Ca(NO3)2.4H2O and (NH4)2HPO4 were used to synthesize HA in situ. MWCNT were functionalized by heating at 1000C in 3:1 ratio of H2SO4 and HNO3 for 60 m with stirring and dispersed in Sodium Dodecyl Benzene Sulphonate (SDBS) by sonication. Hydroxy Apatite (HA) particles were produced in MWCNTs solution by adding Ca(NO3)2.4H2O and (NH4)2HPO4 under vigorously stirring conditions. The composite were dried and washed in distilled water followed by heat treatment at 2500C to obtain CNT-HA powder. Using FTIR, FESEM and EDS does physicochemical characterization of the composite material. The interaction of f-MWCNT and MWCNT-HA were tested on Bacillus subtilis, P. aeruginosa and C. albicans. The zone of inhibition and MIC studies were carried out with a concentration range from 62.5 – 1000 μg/ml. The test result shows no zone of inhibition and MIC > 1000 μg/ml on bacteria and yeast. This result provides further evidence that the bio-nano interface can be developed for Carbon Nanotubes reinforced Hydroxyapatite composites for load-bearing bone implants, drug delivery and diagnostic applications.

Study on Three-Dimensional Reconstruction of the Individualized Maxillofacial Soft and Hard Tissue

The three-dimensional modeling of the maxillofacial soft and hard tissue has a great significance for the study of facial growth and development, diagnosis and treatment of facial deformity, postoperative face prediction and treatment evaluation. The key technology of the maxillofacial soft and hard tissue reconstruction is described.

Adipose Stem Cells Used to Reconstruct 13 Cases With Cranio-Maxillofacial Hard-Tissue Defects

Although isolated reports of hard-tissue reconstruction in the cranio-maxillofacial skeleton exist, multipatient case series are lacking. This study aimed to review the experience with 13 consecutive cases of cranio-maxillofacial hard-tissue defects at four anatomically different sites, namely frontal sinus (3 cases), cranial bone (5 cases), mandible (3 cases), and nasal septum (2 cases). Autologous adipose tissue was harvested from the anterior abdominal wall, and adipose-derived stem cells were cultured, expanded, and then seeded onto resorbable scaffold materials for subsequent reimplantation into hard-tissue defects. The defects were reconstructed with either bioactive glass or β-tricalcium phosphate scaffolds seeded with adipose-derived stem cells (ASCs), and in some cases with the addition of recombinant human bone morphogenetic protein-2. Production and use of ASCs were done according to good manufacturing practice guidelines. Follow-up time ranged from 12 to 52 months. Successful integration of the construct to the surrounding skeleton was noted in 10 of the 13 cases. Two cranial defect cases in which nonrigid resorbable containment meshes were used sustained bone resorption to the point that they required the procedure to be redone. One septal perforation case failed outright at 1 year because of the postsurgical resumption of the patient's uncontrolled nasal picking habit.

Synthesis and Characterization of Carbon Nanotubes Reinforced Hydroxyapatite Composite

Hydroxy Apatite (HA), as a bone mineral component, has been an attractive bioceramic for the reconstruction of hard tissues. However, its poor mechanical properties, including low fracture toughness and tensile strength, have been a significant challenge to the application of HA for the replacement of load-bearing and/or large bone defects. 0.5 M Ca(NO 3 ) 2 .4H 2 O and 0.5 M (NH 4 ) 2 HPO 4 were used to synthesize HA in situ. Multiwalled Carbon Nanotubes were functionalized by heating at 100°C in 3:1 ratio of 20% H 2 SO 4 and 20% HNO 3 for 60 m with stirring. Functionalized MWCNTs were dispersed in Sodium Dodecyl Benzene Sulphonate (SDBS) (10g L −1 ) by sonication. Hydroxy Apatite (HA) particles were produced in MWCNTs solution by adding 0.5 M Ca(NO 3 ) 2 .4H 2 O and 0.5 M (NH 4 ) 2 HPO 4 under vigorously stirring conditions. The composite were dried at 60°C followed by washing in distilled water for 3 to 4 times. Heat treatment at 250°C was done for 30 min to obtain CNT-HA powder. Solution of Polyvinyl Alcohol (PVA) (10g L −1 ) was made by stirring correct quantities of polymer and distilled water at 90°C continuously for 2h. The MWCNT solution in SDBS and MWCNT-HA composite, which has been prepared in advance, was added to the PVA solution and sonicated for 2h in a sonic bath followed by subsequently casting, and controlled water evaporation. PVA/MWCNTs and PVA/MWCNTs/HA composite films were obtained by peeling off from the glass plate substrates and kept in a vacuum desiccator until analyzed. Using FTIR, FESEM, EDS and UTM perform physicochemical characterization of the composite material. FTIR shows the attachments of PO4 and CO3 groups on the composites, which has been further investigated by FESEM and EDS analysis. The EDS results confirmed the presence of the elements such as Ca, P and C in the respective samples. The FESEM confirms HA nanoparticles are densely decorated on MWCNTs. The UTM results shows that overall mechanical properties of the MWCNT-HA composites are significantly improved with increasing concentration of MWCNTs as compared to the PVA film. The organization of CNTs and HA implemented at the nanoscale can further be developed in the form of coatings, nanocomposites, and hybrid powders to enable potential applications in hard tissue reconstruction.

Bio‐inspired dicalcium phosphate anhydrate/poly(lactic acid) nanocomposite fibrous scaffolds for hard tissue regeneration: In situ synthesis and electrospinning

The fundamental building blocks of hierarchically structured bone tissue are mineralized collagen fibrils with calcium phosphate nanocrystals that are biologically "engineered" through biomineralization. In this study, we demonstrate an original invention of dicalcium phosphate anhydrate (DCPA)/poly(lactic acid) (PLA) composite nanofibers, which mimics the mineralized collagen fibrils via biomimetic in situ synthesis and electrospinning for hard tissue regenerative medicines. The interaction of the Ca(2+) ions and the carbonyl groups in the PLA provides nucleation sites for DCPA during the in situ synthesis process. This resulted in the improved dispersion of DCPA nanocrystallites in the intrananoporous PLA nanofibers through electrospinning, compared to the severely agglomerated clusters of DCPA nanoparticles fabricated by conventional mechanical blending/electrospinning methods. The addition of poly(ethylene glycol), as a copolymer source, generated more stable and efficient electrospun jets and aided in the electrospinability of the PLA nanofibers incorporating the nanocrystallites. It is expected that the uniformly distributed DCPA nanocrystallites and its unique nanocomposite fibrous topography will enhance the biological performance and the structural stability of the scaffolds used for hard tissue reconstruction and regeneration.

OP107: Reconstructive surgery in oral maxillofacial and head neck region

Surgery of oral cancer was unique so as to its important anatomical structure in head and neck region.The tissue and functional defect was along with radical surgery. Soft and hard tissue reconstruction was obligatory. Free flap reconstruction was prior in large and complex defect. From 1979 to 2011, 3530 soft free flaps included forearm flap, latissimus dorsi myocutaneous flap, pectoralis major myocutaneous flap (PMMF), anterial lateral thigh flap and lateral arm flap, etc. And almost 1200 hard free flaps consisted of fibular myocutaneous flap, iliac myocutaneous flap and scapula myocutaneous flap. The successful rate increased from 92% in 1980s to 98.5% nowadays, 96.8% in average. The forearm flap and fibular was the most common flap in soft and hard tissue reconstruction of the defects. Anterial lateral thigh flap provided us much more flexible choice for reconstruction of the different defects. The fibular flap coordinated with new technique of dental implant distracted (DID) was effective in simultaneous dental implant of patients in mandibular reconstruction.

Closure of Large Palatal Defect Using a Tongue Flap

The aim of this study is to report the effectiveness of a tongue flap for covering a large hard and soft tissue defect following cleft of the palate. A young patient diagnosed with acute lymphoblastic leukemia underwent a surgical reconstruction of the cleft palate by Le Fort I osteotomy and palatal closure utilizing a tongue flap. The flap provided sound and lasting closure after the surgery, and the patient successfully healed. Our goal is to present this unique case and highlight how postoperative results were good, safe, and predictable. We also hope to show that tongue transplantation as flap for hard and soft tissue reconstruction represents a valuable option in reconstruction, given the proper circumstances.

Osteogenesis of cryopreserved osteogenic matrix cell sheets

Cryopreservation of tissue engineered bone (TEB), whilst maintaining its osteogenic ability, is imperative for large-scale clinical application. We previously reported a novel cell transplantation method, in which bone-marrow-derived mesenchymal stem cells (BMSCs) were cultured to confluence and differentiated down the osteogenic lineage to form osteogenic matrix cell sheets (OMCS). OMCS have high alkaline phosphatase (ALP) activity and osteocalcin (OC) contents and can be easily used for producing TEB. The aim of the present study was to investigate whether TEB produced by cryopreserved OMCS maintains sufficient osteogenic potential in vivo. OMCS were prepared and divided into three groups according to storage period of cryopreservation (fresh (no cryopreservation), 4week and 12week cryopreservation groups). OMCS were cryopreserved by storage in freezing medium (Cell Banker 1®) at −80°C. Cryopreserved OMCSs were rapidly thawed at room temperature and wrapped around Hydroxyapatite (HA) scaffolds prior to implantation into subcutaneous sites in rats, to determine their in vivo bone-forming capability. The constructs were harvested 4weeks after transplantation and examined histologically and biochemically. Histological analysis of the constructs showed extensive bone formation in the HA pores with high ALP activity and OC content detected in the cryopreservation groups. The present study clearly indicates that cryopreserved/thawed OMCS are still capable of producing mineralized matrix on scaffolds, resulting in bone formation. This cryopreservation technique could be applied for hard tissue reconstruction to ease the cell preparation method prior to time of use.

English

early, although, surprisingly, it is not always necessary. Haemodynamic resuscitation, followed by thorough patient evaluation, is done to rule out concomitant injuries often associated with warfare injuries. They may go unnoticed when attention is directed primarily to an extensive facial injury 4–7 . After early resuscitation, careful history and physical examination and paraclinical diagnostics are necessary for correct management. Craniofacial computed tomography-scans with soft tissue and bone imaging in different views (axial, coronal and three dimensional) are the procedures of choice for diagnosis of facial injuries. Consultation with different specialists is often necessary for treatment. Surgical management of facial gunshot wounds is basically divided into three stages: (1) debridement, fracture stabilisation, and primary closure; (2) reconstruction of hard tissues, provided soft tissue coverage is adequate; and (3) rehabilitation of the oral vestibule, alveolar ridge, and secondary correction of residual deformities and dental implants 6,8 . Herein, we review and evaluate the current trends in the management of maxillofacial gunshot injuries. Discussion The authors have referenced some of their own studies in this review. These referenced studies have been conducted in accordance with the Declaration of Helsinki (1964) and the protocols of these studies have been approved by the relevant ethics committees related to the institution in which they were performed. All human subjects, in these referenced studies, gave informed consent to participate in these studies. Debridement