This study is a preliminary investigation exploring the mechanical properties of three-dimensional (3D)-printed personalized mesh titanium alloy prostheses and the feasibility of repairing hemi-mandibular defects. The ANSYS 14.0 software and selective laser melting (SLM) were used to produce personalized mesh titanium alloy scaffolds. Scaffolds printed using different parameters underwent fatigue property tests and scanning electron microscopy (SEM) of the fracture points. Models of hemi-mandibular defects (encompassing the temporomandibular joint) were created using beagle dogs. Freeze-dried allogeneic mandibles or 3D-printed personalized mesh titanium alloy prostheses were used for repair. Gross observation, computed tomography (CT), SEM, and histological examinations were used to compare the two repair methods. The prostheses with filament diameters of 0.5 and 0.7 mm could withstand 14,000 times and >600,000 cycles of alternating stresses, respectively. The truss-structure scaffold with a large aperture and large aperture ratio could withstand roughly 250,000 cycles of alternating forces. The allogeneic mandible graft required intraoperative shaping, while the 3D-printed mesh titanium alloy prostheses were personalized and did not require intraoperative shaping. The articular disc on the non-operated sides experienced degenerative changes. No liver and kidney toxicity was observed in the two groups of animals. The 3D-printed mesh titanium alloy prostheses could effectively restore the shape of the mandibular defect region and reconstruct the temporomandibular joint.

OBJECTIVE: To evaluate the effects of concentrated growth factor (CGF), combined with a mixture of iliac cancellous and composite bone materials, on the repair of extensive mandibular defects.
METHODS: This clinical trial involved patients with mandibular defects caused by large cystic lesions. The test group comprised 16 patients who underwent CGF combined with iliac cancellous bone and composite bone materials to repair extensive mandibular defects, whereas the control group comprised eight patients who underwent vascularised free fibula grafts for mandibular segmental defects. Postoperative exudatum was collected from patients on the 1st, 2nd, 3rd, and 4th days postoperatively, and osteogenic factor, including alkaline phosphatase (ALP), osteocalcin (BGP), and procollagen type I N-terminal propeptide (PINP), and inflammatory cytokines were performed. Additionally, regular cone beam computed tomography (CBCT) scans were conducted before and after surgery.
RESULTS: On postoperative days 1-4, the expression levels of ALP, BGP, and PINP were higher in the test group, while those of IL-1α, IL-1β, IL-6, IL-8, and TNF-α, which were identified as co-differentially expressing inflammatory cytokines, were all down-regulated in the exudatum of the test group. Regular CBCT radiological scans revealed a significant osteogenic effect in the test group.
CONCLUSIONS: The use of CGF combined with iliac cancellous bone and composite bone materials to repair extensive mandibular jaw defects facilitates bone formation and reductions in inflammation in the defect area in the short term, which deserves further research in clinical practice.

Objective:To investigate the application of free fibular flap based on digital technology in mandibular defects. Method:Eight cases of mandibular defects underwent virtual surgery and guide plate design before operation. The mandibular osteotomy guide plate, fibula plastic guide plate and mandibular reconstruction model were prepared by rapid prototyping technology. The individualized reconstruction titanium plates were prefabricated on the mandibular reconstruction model. Based on the guide plates and the individualized reconstruction titanium plates, the mandibular defects were repaired accurately. At the same time, CT angiography was used to observe the variation of peroneal artery. For patients with soft tissue defects, the superficial position of the point going out muscle of perforator vessels was located, and the skin flaps were designed to repair the soft tissue defect. Result:The free fibular flaps survived in all patients. The guide plates were successfully implanted, the position of the individualized reconstruction titanium plates were accurate, and the occlussions were well recovered. Preoperative CT angiography was carried out without complication in all patients, the desired anatomy was adequately demonstrated in all patients. The superficial position of the point going out muscle of perforator vessels during operation were basically in accordance with those detected by CT angiography. Conclusion:The free fibular flaps based on digital technology can successfully repair mandibular defects with good aesthetic and functional results.
目的：探讨基于数字化技术的游离腓骨肌皮瓣在下颌骨缺损中的应用价值。 方法：8例拟行游离腓骨肌皮瓣修复手术的患者，术前行虚拟手术及导板设计，利用快速成型技术制备下颌骨截骨导板、腓骨塑形导板以及下颌骨修复后模型，在下颌骨修复后模型上预制个体化重建钛板，术中根据导板和个体化重建钛板，完成对下颌骨缺损的精确修复。同时通过术前下肢CT血管造影观察腓动脉有无变异，对合并软组织缺损的患者，定位穿支血管出肌点的体表位置，以其为中心设计皮瓣，完成软组织缺损的修复。 结果：8例患者术后移植游离腓骨肌皮瓣均成活，导板术中就位顺利，个体化重建钛板位置准确，患者咬合关系恢复良好。术前CT血管造影检查顺利，CT血管造影可以准确显示腓动脉的解剖位置，定位穿支血管出肌点的体表位置与术中所见完全吻合。 结论：基于数字化技术的游离腓骨肌皮瓣能够成功修复下颌骨缺损，获得良好的美观和功能效果。.

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.

Rehabilitation of gunshot injuries that require combined reconstruction of bone and soft tissue poses a considerable challenge. We describe three cases of rehabilitation for mandibular defects and deformities caused by gunshot injuries. After debridement, three kinds of internal distractors were used. The bony transport discs were distracted about 10-22mm, and the new bone formed well in the distracted gaps. There was no evidence of infection during the consolidation period or follow up. Aesthetic appearance was also pleasing after treatment. Internal distraction osteogenesis after debridement might be a practical way of synchronously reconstructing bony and soft tissue after mandibular gunshot injuries.

Mandibles are the largest and strongest bone in the human face and are often severely compromised by mandibular defects, compromising the quality of life of patients. Mandibular defects may result from trauma, inflammatory disease and benign or malignant tumours. The reconstruction of mandibular defect has been a research hotspot in oral and maxillofacial surgery. Although the principles and techniques of mandibular reconstruction have made great progress in recent years, the development of biomedical materials is still facing technical bottleneck, and new materials directly affect technological breakthroughs in this field. This paper reviews the current status of research and application of various biomaterials in mandibular defects and systematically elaborates different allogeneic biomaterial-based approaches. It is expected that various biomaterials, in combination with new technologies such as digital navigation and 3D printing, could be tuned to build new types of scaffold with more precise structure and components, addressing needs of surgery and post-reconstruction. With the illustration and systematization of different solutions, aims to inspire the development of reconstruction biomaterials.

The novel synthetic peptide P17-BMP-2 could promote cell attachment and enhance osteogenic capability. A composite, comprising nano-hydroxyapatite, collagen and poly(L-lactide) (nHAC/PLLA), was an efficient scaffold for carrier of P17-BMP-2. Our aim was to investigate whether nHAC/PLLA/P17-BMP-2 accelerates the osteogenesis as a reliable method for mandibular defect healing in this study. The repair capability was assessed by the gross observation, X-ray test and histological observation in four animal experiment groups at 2 week and 4 week after surgery: Group A (control), Group B (nHAC/PLLA treatment), Group C (nHAC/PLLA with 2 mg/g P17-BMP-2 treatment) and Group D (nHAC/PLLA with 10 mg/g P17-BMP-2 treatment). The Lane-Sandhu X-ray scores of the four groups were compared among four groups as well. The results showed that the composites containing the highest content of P17- BMP-2 performed best. Therefore, the nHAC/PLLA with P17-BMP-2 composite can accelerate the osteogenesis for mandibular defect healing and could be an ideal biological material as a bone graft material option for clinical applications.

Ameloblastomas are slowly growing, locally invasive tumors with high recurrence rate and more common in the mandible, if not treated they can grow to enormous size. Radical resection is the only predictable form of treatment for ameloblastomas. However, mandibular resection can lead to dysfunctions in appearance, speech, mastication, and deglutition, which severely impair the patients\' quality of life. The reconstruction of extensive bone defects in the maxillofacial area is still challenging. To meet the demands of functional reconstruction, minimizing the negative influence of mandibular malformation, and disability on patients, the individualized systematic treatment plans highlight denture prosthodontics and require much consideration of multidisciplinary cooperation, with such related fields as maxillofacial surgery, oral implantology, prosthodontics, and radiology taken into account. In this report, we will present a case of reconstructing the mandibular segmental defect after the resection of a rarely giant ameloblastoma. In the case, we took the restoration of the missing teeth and the rehabilitation of the masticatory function as well as restoring bony continuities and facial appearance into consideration, communicated well with prosthodontists and implantologists before surgery, making the individualized systematic treatment plan more effective and efficient.