BACKGROUND Critically sized bone defects represent a significant challenge to orthopaedic surgeons worldwide.These defects generally result from severe trauma or resection of a whole large tumour.Autologous bone graft...BACKGROUND Critically sized bone defects represent a significant challenge to orthopaedic surgeons worldwide.These defects generally result from severe trauma or resection of a whole large tumour.Autologous bone grafts are the current gold standard for the reconstruction of such defects.However,due to increased patient morbidity and the need for a second operative site,other lines of treatment should be introduced.To find alternative unconventional therapies to manage such defects,bone tissue engineering using a combination of suitable bioactive factors,cells,and biocompatible scaffolds offers a promising new approach for bone regeneration.AIM To evaluate the healing capacity of platelet-rich fibrin(PRF)membranes seeded with allogeneic mesenchymal bone marrow-derived stem cells(BMSCs)on critically sized mandibular defects in a rat model.METHODS Sixty-three Sprague Dawley rats were subjected to bilateral bone defects of critical size in the mandibles created by a 5-mm diameter trephine bur.Rats were allocated to three equal groups of 21 rats each.Group I bone defects were irrigated with normal saline and designed as negative controls.Defects of group II were grafted with PRF membranes and served as positive controls,while defects of group III were grafted with PRF membranes seeded with allogeneic BMSCs.Seven rats from each group were killed at 1,2 and 4 wk.The mandibles were dissected and prepared for routine haematoxylin and eosin(HE)staining,Masson's trichrome staining and CD68 immunohistochemical staining.RESULTS Four weeks postoperatively,the percentage area of newly formed bone was significantly higher in group III(0.88±0.02)than in groups I(0.02±0.00)and II(0.60±0.02).The amount of granulation tissue formation was lower in group III(0.12±0.02)than in groups I(0.20±0.02)and II(0.40±0.02).The number of inflammatory cells was lower in group III(0.29±0.03)than in groups I(4.82±0.08)and II(3.09±0.07).CONCLUSION Bone regenerative quality of critically sized mandibular bone defects in rats was better promoted by PRF membranes seeded with BMSCs than with PRF membranes alone.展开更多
Mandibular defect occurs more frequently in recent years,and clinical repair operations via bone transplantation are difficult to be further improved due to some intrinsic flaws.Tissue engineering,which is a hot resea...Mandibular defect occurs more frequently in recent years,and clinical repair operations via bone transplantation are difficult to be further improved due to some intrinsic flaws.Tissue engineering,which is a hot research field of biomedical engineering,provides a new direction for mandibular defect repair.As the basis and key part of tissue engineering,scaffolds have been widely and deeply studied in regards to the basic theory,as well as the principle of biomaterial,structure,design,and fabrication method.However,little research is targeted at tissue regeneration for clinic repair operations.Since mandibular bone has a special structure,rather than uniform and regular structure in existing studies,a methodology based on tissue engineering is proposed for mandibular defect repair in this paper.Key steps regarding scaffold digital design,such as external shape design and internal microstructure design directly based on triangular meshes are discussed in detail.By analyzing the theoretical model and the measured data from the test parts fabricated by rapid prototyping,the feasibility and effectiveness of the proposed methodology are properly verified.More works about mechanical and biological improvements need to be done to promote its clinical application in future.展开更多
Objective To study feasibility and value of repair of oral mandibular defects with rib composite flap pedicled with internal thoracic vessels in basic level hospitals. Methods The clinical materials in 13 cases uith m...Objective To study feasibility and value of repair of oral mandibular defects with rib composite flap pedicled with internal thoracic vessels in basic level hospitals. Methods The clinical materials in 13 cases uith mandibular defects which were repaired with rib compos-展开更多
Experiments on maxillofacial bone tissue engineering showed the promising result;however, its healing mechanisms and effectiveness had not been fully understood. The aim of this study is to compare the bone healing me...Experiments on maxillofacial bone tissue engineering showed the promising result;however, its healing mechanisms and effectiveness had not been fully understood. The aim of this study is to compare the bone healing mechanism and osteogenic capacity between bovine bone mineral loaded with hAMSC and autogenous bone graft in the reconstruction of critical size mandibular bone defect. Critical size defects were made at the mandible of 45 New Zealand white rabbits reconstructed with BBM-hAMSC, BBM alone, and ABG, respectively. At the end of first, second, and twelfth weeks, five rabbits from each experimental week were sacrificed for histology and immunohistochemistry staining. Expressions of vascular endothelial growth factor (VEGF), bone mor-phogenic proteins-2 (BMP2), Runx2 and the amount of angiogenesis were analyzed in the first and second week groups, while expressions of Runx2, osteocalcin, collagen type-I fibres, trabecular area and bone incorporation were analyzed in the twelfth week groups. The result showed that expressions of VEGF, BMP2 and Runx2 as well as the amount of angiogenesis were higher in ABG compared with BBM-hAMSC group in the first and second weeks of healing. The result of twelfth week of healing showed that expressions of Runx2 and osteocalcin as well as the thickness of collagen type-I fibres were significantly higher in BBM-hAMSC compared to ABG group, while there was no statistically difference in trabecular area and bone incorporation between BBM-hAMSC and ABG group. This study concluded that early healing activities were higher in auto-genous bone graft than in BBM-hAMSC, while osteogenic activities in the late stage of healing were higher in BBM-hAMSC compared to autogenous bone graft. It was also concluded that the osteo-genic capacity of BBM-hAMSC was comparable to autogenous bone graft in the reconstruction of critical size defect in the mandible.展开更多
To discuss the feasibility of the application of porous Mg-Sr alloy combined with Mg-Sr alloy membrane in the repair of mandibular defects in dogs.The second and third mandibular premolars on both sides were extracted...To discuss the feasibility of the application of porous Mg-Sr alloy combined with Mg-Sr alloy membrane in the repair of mandibular defects in dogs.The second and third mandibular premolars on both sides were extracted from six dogs.The model of mandible buccal fenestration bone defects were prepared after the sockets healed.Twelve bone defects were randomly divided into groups A and B,then Mg-Sr alloy was implanted in bone defects of group A and covered by Mg-Sr alloy membrane while Mg-Sr alloy was implanted in bone defects of group B and covered by mineralized collagen membrane.Bone defects observed on cone beam computed tomographic images and comparing the gray value of the two groups after 4,8 and 12 weeks.After 12 weeks,the healing of bone defects were evaluated by gross observation,X-ray microscopes and histological observation of hard tissue.Bone defects in each group were repaired.At 8 and 12 weeks,the gray value of group A was higher than that of group B(P<0.05).At 12 weeks,the bone volume fraction of group A was higher than that of group B(P<0.05).The newly woven bone in group A is thick and arranged staggered,which was better than that of group B.Porous Mg-Sr alloy combined with Mg-Sr alloy membrane could further promote the repair of mandibular defects,and obtain good osteogenic effect.展开更多
Background:Three-dimensional(3D)printed tissue engineered bone was used to repair the bone tissue defects in the oral and maxillofacial(OMF)region of experimental dogs.Material and methods:Canine bone marrow stromal c...Background:Three-dimensional(3D)printed tissue engineered bone was used to repair the bone tissue defects in the oral and maxillofacial(OMF)region of experimental dogs.Material and methods:Canine bone marrow stromal cells(BMSCs)were obtained from 9 male Beagle dogs and in vitro cultured for osteogenic differentiation.The OMF region was scanned for 3D printed surgical guide plate and mold by ProJet1200 high-precision printer using implant materials followed sintering at 1250℃.The tissue engineered bones was co-cultured with BASCs for 2 or 8 d.The cell scaffold composite was placed in the defects and fixed in 9 dogs in 3 groups.Postoperative CT and/or micro-CT scans were performed to observe the osteogenesis and material degradation.Results:BMSCs were cultured with osteogenic differentiation in the second generation(P2).The nanoporous hydroxyapatite implant was made using the 3D printing mold with the white porous structure and the hard texture.BMSCs with osteogenic induction were densely covered with the surface of the material after co-culture and ECM was secreted to form calcium-like crystal nodules.The effect of the tissue engineered bone on the in vivo osteogenesis ability was no significant difference between 2 d and 8 d of the compositing time.Conclusions:The tissue-engineered bone was constructed by 3D printing mold and hightemperature sintering to produce nanoporous hydroxyapatite scaffolds,which repair in situ bone defects in experimental dogs.The time of compositing for tissue engineered bone was reduced from 8 d to 2 d without the in vivo effect.展开更多
This study aimed to propose a novel biomimetic design strategy of an oral implant and to numerically examine its biomechanical effect according to clinical interests.The designed implant conceptually mimicked the morp...This study aimed to propose a novel biomimetic design strategy of an oral implant and to numerically examine its biomechanical effect according to clinical interests.The designed implant conceptually mimicked the morphology and elastic modulus of the mandibular bone.Basing on a CT-image-based patient-specific reconstruction of the tumor-excised mandible,the biomechanical effects of the implants with three materials(PEEK/n-HA/CF,PEEK/HA and Ti6Al4V),two surgical conditions(removed and retained muscles),and two postoperative stages(early and late)were fully investigated by a static finite element analysis.Moreover,according to clinical interests(e.g.failure and stability of the implant and rivets),maximum von Mises stresses and strains of the implant and rivets,maximum implant-bone gap in the early postoperative stage,and maximum von Mises stress of the mandible were mainly analyzed.The results showed that the implant composed of Ti6Al4V material was suitable for the current design strategy with respect to the other two PEEK-based materials.Although the implants in the muscle-retained surgical condition had relative greater indices compared to the muscle-removed surgical condition,the index difference between the two conditions was slight.The biomechanical indices indicating the failure and loosening risks of implant and rivets were much reduced in the late postoperative stage with respect to the early postoperative stage due to the osteointegration at the implant-bone interface.Generally,the proposed novel design strategy could be useful to guide the design of the oral implant addressing different implant materials and surgical conditions,and further made proper suggestion to clinicians and patients.展开更多
Ameloblastoma is the most frequent odontogenic tumor of the jaw. If not treated, ameloblastoma can gain an enormous size and cause severe facial disfigurement and functional impairment. Here we report two patients aff...Ameloblastoma is the most frequent odontogenic tumor of the jaw. If not treated, ameloblastoma can gain an enormous size and cause severe facial disfigurement and functional impairment. Here we report two patients afflicted with extensive mandibular ameloblastoma (sized in 23 cm × 18 cm × 17 cm and 15 cm × 12 cm × 10 cm, respectively). Both the patients received the same sequential treatment including radical tumor resection, simultaneous reconstruction with fibula free flap graft, vertical distraction osteogenesis on the fibula graft, placement of endosseous dental implants, and final pros-thodontic rehabilitation. It took about 15 months to finish the entire course of treatment. And after the four-year follow-up, neither soft tissue related, nor hard tissue related problems were observed. Satisfactory facial symmetry, chewing and speech functions of the patients were restored. So this sequential treatment for extensive mandibular ameloblastoma can obtain an excellent effect by the shortest time and the lowest economical cost. Furthermore, the series also can be used to reconstruct giant mandibular defects caused by different reasons.展开更多
文摘BACKGROUND Critically sized bone defects represent a significant challenge to orthopaedic surgeons worldwide.These defects generally result from severe trauma or resection of a whole large tumour.Autologous bone grafts are the current gold standard for the reconstruction of such defects.However,due to increased patient morbidity and the need for a second operative site,other lines of treatment should be introduced.To find alternative unconventional therapies to manage such defects,bone tissue engineering using a combination of suitable bioactive factors,cells,and biocompatible scaffolds offers a promising new approach for bone regeneration.AIM To evaluate the healing capacity of platelet-rich fibrin(PRF)membranes seeded with allogeneic mesenchymal bone marrow-derived stem cells(BMSCs)on critically sized mandibular defects in a rat model.METHODS Sixty-three Sprague Dawley rats were subjected to bilateral bone defects of critical size in the mandibles created by a 5-mm diameter trephine bur.Rats were allocated to three equal groups of 21 rats each.Group I bone defects were irrigated with normal saline and designed as negative controls.Defects of group II were grafted with PRF membranes and served as positive controls,while defects of group III were grafted with PRF membranes seeded with allogeneic BMSCs.Seven rats from each group were killed at 1,2 and 4 wk.The mandibles were dissected and prepared for routine haematoxylin and eosin(HE)staining,Masson's trichrome staining and CD68 immunohistochemical staining.RESULTS Four weeks postoperatively,the percentage area of newly formed bone was significantly higher in group III(0.88±0.02)than in groups I(0.02±0.00)and II(0.60±0.02).The amount of granulation tissue formation was lower in group III(0.12±0.02)than in groups I(0.20±0.02)and II(0.40±0.02).The number of inflammatory cells was lower in group III(0.29±0.03)than in groups I(4.82±0.08)and II(3.09±0.07).CONCLUSION Bone regenerative quality of critically sized mandibular bone defects in rats was better promoted by PRF membranes seeded with BMSCs than with PRF membranes alone.
基金Project supported by the National Natural Science Foundation of China (No. 50905164)the Zhejiang Provincial Natural Science Foundation of China (No. Y2090835)
文摘Mandibular defect occurs more frequently in recent years,and clinical repair operations via bone transplantation are difficult to be further improved due to some intrinsic flaws.Tissue engineering,which is a hot research field of biomedical engineering,provides a new direction for mandibular defect repair.As the basis and key part of tissue engineering,scaffolds have been widely and deeply studied in regards to the basic theory,as well as the principle of biomaterial,structure,design,and fabrication method.However,little research is targeted at tissue regeneration for clinic repair operations.Since mandibular bone has a special structure,rather than uniform and regular structure in existing studies,a methodology based on tissue engineering is proposed for mandibular defect repair in this paper.Key steps regarding scaffold digital design,such as external shape design and internal microstructure design directly based on triangular meshes are discussed in detail.By analyzing the theoretical model and the measured data from the test parts fabricated by rapid prototyping,the feasibility and effectiveness of the proposed methodology are properly verified.More works about mechanical and biological improvements need to be done to promote its clinical application in future.
文摘Objective To study feasibility and value of repair of oral mandibular defects with rib composite flap pedicled with internal thoracic vessels in basic level hospitals. Methods The clinical materials in 13 cases uith mandibular defects which were repaired with rib compos-
文摘Experiments on maxillofacial bone tissue engineering showed the promising result;however, its healing mechanisms and effectiveness had not been fully understood. The aim of this study is to compare the bone healing mechanism and osteogenic capacity between bovine bone mineral loaded with hAMSC and autogenous bone graft in the reconstruction of critical size mandibular bone defect. Critical size defects were made at the mandible of 45 New Zealand white rabbits reconstructed with BBM-hAMSC, BBM alone, and ABG, respectively. At the end of first, second, and twelfth weeks, five rabbits from each experimental week were sacrificed for histology and immunohistochemistry staining. Expressions of vascular endothelial growth factor (VEGF), bone mor-phogenic proteins-2 (BMP2), Runx2 and the amount of angiogenesis were analyzed in the first and second week groups, while expressions of Runx2, osteocalcin, collagen type-I fibres, trabecular area and bone incorporation were analyzed in the twelfth week groups. The result showed that expressions of VEGF, BMP2 and Runx2 as well as the amount of angiogenesis were higher in ABG compared with BBM-hAMSC group in the first and second weeks of healing. The result of twelfth week of healing showed that expressions of Runx2 and osteocalcin as well as the thickness of collagen type-I fibres were significantly higher in BBM-hAMSC compared to ABG group, while there was no statistically difference in trabecular area and bone incorporation between BBM-hAMSC and ABG group. This study concluded that early healing activities were higher in auto-genous bone graft than in BBM-hAMSC, while osteogenic activities in the late stage of healing were higher in BBM-hAMSC compared to autogenous bone graft. It was also concluded that the osteo-genic capacity of BBM-hAMSC was comparable to autogenous bone graft in the reconstruction of critical size defect in the mandible.
基金supported by Science and Technology Fund of Liaoning Province(20180530071).
文摘To discuss the feasibility of the application of porous Mg-Sr alloy combined with Mg-Sr alloy membrane in the repair of mandibular defects in dogs.The second and third mandibular premolars on both sides were extracted from six dogs.The model of mandible buccal fenestration bone defects were prepared after the sockets healed.Twelve bone defects were randomly divided into groups A and B,then Mg-Sr alloy was implanted in bone defects of group A and covered by Mg-Sr alloy membrane while Mg-Sr alloy was implanted in bone defects of group B and covered by mineralized collagen membrane.Bone defects observed on cone beam computed tomographic images and comparing the gray value of the two groups after 4,8 and 12 weeks.After 12 weeks,the healing of bone defects were evaluated by gross observation,X-ray microscopes and histological observation of hard tissue.Bone defects in each group were repaired.At 8 and 12 weeks,the gray value of group A was higher than that of group B(P<0.05).At 12 weeks,the bone volume fraction of group A was higher than that of group B(P<0.05).The newly woven bone in group A is thick and arranged staggered,which was better than that of group B.Porous Mg-Sr alloy combined with Mg-Sr alloy membrane could further promote the repair of mandibular defects,and obtain good osteogenic effect.
基金The study was approved by the Animal Experimental Enthical Review From Of Southwest Medical University.Informed consent was obtained。
文摘Background:Three-dimensional(3D)printed tissue engineered bone was used to repair the bone tissue defects in the oral and maxillofacial(OMF)region of experimental dogs.Material and methods:Canine bone marrow stromal cells(BMSCs)were obtained from 9 male Beagle dogs and in vitro cultured for osteogenic differentiation.The OMF region was scanned for 3D printed surgical guide plate and mold by ProJet1200 high-precision printer using implant materials followed sintering at 1250℃.The tissue engineered bones was co-cultured with BASCs for 2 or 8 d.The cell scaffold composite was placed in the defects and fixed in 9 dogs in 3 groups.Postoperative CT and/or micro-CT scans were performed to observe the osteogenesis and material degradation.Results:BMSCs were cultured with osteogenic differentiation in the second generation(P2).The nanoporous hydroxyapatite implant was made using the 3D printing mold with the white porous structure and the hard texture.BMSCs with osteogenic induction were densely covered with the surface of the material after co-culture and ECM was secreted to form calcium-like crystal nodules.The effect of the tissue engineered bone on the in vivo osteogenesis ability was no significant difference between 2 d and 8 d of the compositing time.Conclusions:The tissue-engineered bone was constructed by 3D printing mold and hightemperature sintering to produce nanoporous hydroxyapatite scaffolds,which repair in situ bone defects in experimental dogs.The time of compositing for tissue engineered bone was reduced from 8 d to 2 d without the in vivo effect.
基金This work is partially supported by the National Nature Science Foundation of China(32171307,11972118,11772093)ARC(DP200103492,DP200101970).
文摘This study aimed to propose a novel biomimetic design strategy of an oral implant and to numerically examine its biomechanical effect according to clinical interests.The designed implant conceptually mimicked the morphology and elastic modulus of the mandibular bone.Basing on a CT-image-based patient-specific reconstruction of the tumor-excised mandible,the biomechanical effects of the implants with three materials(PEEK/n-HA/CF,PEEK/HA and Ti6Al4V),two surgical conditions(removed and retained muscles),and two postoperative stages(early and late)were fully investigated by a static finite element analysis.Moreover,according to clinical interests(e.g.failure and stability of the implant and rivets),maximum von Mises stresses and strains of the implant and rivets,maximum implant-bone gap in the early postoperative stage,and maximum von Mises stress of the mandible were mainly analyzed.The results showed that the implant composed of Ti6Al4V material was suitable for the current design strategy with respect to the other two PEEK-based materials.Although the implants in the muscle-retained surgical condition had relative greater indices compared to the muscle-removed surgical condition,the index difference between the two conditions was slight.The biomechanical indices indicating the failure and loosening risks of implant and rivets were much reduced in the late postoperative stage with respect to the early postoperative stage due to the osteointegration at the implant-bone interface.Generally,the proposed novel design strategy could be useful to guide the design of the oral implant addressing different implant materials and surgical conditions,and further made proper suggestion to clinicians and patients.
文摘Ameloblastoma is the most frequent odontogenic tumor of the jaw. If not treated, ameloblastoma can gain an enormous size and cause severe facial disfigurement and functional impairment. Here we report two patients afflicted with extensive mandibular ameloblastoma (sized in 23 cm × 18 cm × 17 cm and 15 cm × 12 cm × 10 cm, respectively). Both the patients received the same sequential treatment including radical tumor resection, simultaneous reconstruction with fibula free flap graft, vertical distraction osteogenesis on the fibula graft, placement of endosseous dental implants, and final pros-thodontic rehabilitation. It took about 15 months to finish the entire course of treatment. And after the four-year follow-up, neither soft tissue related, nor hard tissue related problems were observed. Satisfactory facial symmetry, chewing and speech functions of the patients were restored. So this sequential treatment for extensive mandibular ameloblastoma can obtain an excellent effect by the shortest time and the lowest economical cost. Furthermore, the series also can be used to reconstruct giant mandibular defects caused by different reasons.
