objective: To study the stress distribution of abutment dentin of mandibular complete overdenture based on post core abutment(COBPA). Methods: 3 D FEM was employed to investigate the stress distribution of abutment dentin of mandibular COBPA and natural abutment(NA) on standard model, the data were compared. Results: In the same loading condition, stress concentration was observed at the root end area of dentin in both COBPA and NA. When post core was applied decreased stress distribution area and increased stress value were found aroud tooth neck, decreased stress concentration was found at root end. Conclusion: In COBPA and NA the stress may be transferred to the root end along the axis. Apart from retention, post core can transfer and buffer the stress, change the way of stress transfer, and may result in cervical fracture.

Objective: To enable an artificial mandible substitute to be mostly suitable for mandibular reconstructon in individual patients. Methods: Use rapid prototypinlg and surface imitating as the primary technology for individualized design and manufacturing of the artificial mandible substitute. Results: An individualized artificial mandible substitute was designed and prepared. Conclusion: Rapid prototyping is feasible in individualized bone substitute preparation.

Objective: To enable an artificial mandible substitute to be with individualized shape in the individual patient. Methods: Rapid prototyping and surface imitating were used as the primary technology in the individualized design and manufacturing of the artificial mandible substitute. Results: The shape and size of the manufactured artificial mandibe were almost the same to those of the original natural one. Conclusion: Rapid prototyping may be used in individualized bone substitute preparation.

Objective:To investigate the stress distribution of the edentulous maxilla with unilateral maxillary defect after implant rehabilitation under occlusal loads.Methods:Three dimensional finite element model of the edentulous maxilla with unilateral maxillary defect was build.The stress distribution of the edentulous maxilla under occlusal loads with computer simulated implant rehabilitation was investigated.Results:Regardless of load manner,the stress of the bone around 1 were high when just healthy side implanted,but the stress reduced after implantantion in health side combined with the implantation in zygoma in defect side.Conclusion:Implantation in health side combined with that in zygoma in defect side can reduce the stress of the bone around the implant.

Objective To solve some problem in present cervical spinal disc.MethodsAfter analyzing the function of cervical spinal disc, 2 kinds of materials were chosen to design and fabricate the double-layer cervical spinal disc prosthetic. CAD and ANSYS technologies were used to optimize 4 kinds of the new prosthetic structure.Results and ConclusionThe materials if the prosthetic is proper, and the double-layer column structure of the new prosthetic shows some excellence characteristics,including maximum stress of nucleus and annulus properly, simple structure and can be facilitated and exactly graft.

Focusing on the poor mechanical strength of porous bioceramics bone scaffold, and taking into account of the good mechanical properties of biodegradable magnesium alloy, we proposed a novel method to fabricate magnesium alloy/bioceramics composite bone scaffold with stereolithography double channels. Firstly, a scaffold structure without mutually connected double channels was designed. Then, an optimized bioceramics scaffold was fabricated according to stereolithography and gel-casing. Molten AZ31 magnesium alloy was perfused into the secondary channel of scaffold by low-pressure casting, and magnesium alloy/bioceramics composite bone scaffold was obtained when magnesium alloy was solidified. The compression test showed that the strength of bioceramics scaffold with only one channel and without magnesium alloy was (9.76 ± 0.64) MPa, while the strength of magnesium alloy/bioceramics composite scaffold with double channels was (17.25 ± 0.88) MPa. It can be concluded that the magnesium alloy/bioceramics composite is obviously able to improve the scaffold strength.
Alloys ; Biomechanical Phenomena ; Bone and Bones ; Ceramics ; Humans ; Magnesium ; Materials Testing ; Porosity ; Tissue Scaffolds

Objective Due to the problem of individual matching, exclusivity and loose with pure mechanical fixation for artificial hemi-knee joints made by traditional method, a new manufacturing process based on rapid prototyping technique and custom-made concept is presented.MethodsRapid prototyping was processed to rapidly and accurately shape the prototype of an artificial implant almost with the same shape as the hemi-knee joint of the patient, and the process based on Titanium alloy centrifugal casting technology and biomaterial sintering molding technology was used to fabricate the artificial hemi-knee joint and bioactive proximal tibia artificial bone, respectively.Results and ConclusionThe custom-made knee joint prosthesis has been fabricated and put into clinical use successfully. In comparison with the traditional implants, this system can realize the well matching movement between the artificial hemi-knee joint and its opposite. Meanwhile,the design of functional holes and tibial nails realizes the combination of biological fixation with mechanical fixation for the artificial implant,and the use of bioactive artificial bone promotes bone growth and minimizes the exclusive reaction.

BACKGROUND:With significantly individual differences in the anatomy of the knee joint, traditional total knee replacement is difficult to accurately predict the position of locating limb alignment, size of the prosthesis and osteotomy amount of patients during operation. OBJECTIVE:To investigate the clinical effect of total knee replacement based on the assistance of medical image reconstruction, computer-aided design technology and 3D-printing personalized surgical navigation template. METHODS:Medical image data of patients were col ected using CT or magnetic resonance scanning equipment. The three-dimensional reconstruction of the bone was conducted by two-dimensional medical image processing technology. The navigation template was designed by computer-aided design technology. The personalized surgical navigation templates were produced by 3D printing technology, and the clinical total knee replacement was conducted. The postoperative results were evaluated using imageology. RESULTS AND CONCLUSION:Arigin 3D Pro (Arigin Medical Co., Ltd.) can accurately reconstruct a three-dimensional model of the lower limb bones. The three-dimensional design software Arigin Surgical Templating by their independent research and development can precisely pinpoint related lower limb axis, including limb alignment, rotation axis of the femur and osteotomy reference point. The personalized navigation template we researched and produced for knee surgery fitted tightly with femoral condyle and tibial plateau bone anatomy during operation, without significant movement. The deviation of patients’ limb alignment was less than 3° after total knee replacement.

BACKGROUND:In recent years, many manufacturing techniques have been recently developed for soft tissue engineering scaffolds. Especialy additive manufacturing with a unique material accumulated forming principle can be feasible and reliable to manufacture the highly precise scaffolds with gradient structures and multi-materials for large soft tissue defect repairing.
OBJECTIVE:To summarize scaffolds manufacturing technologies in the soft tissue engineering applications developed in recent years and to predict the direction of development.
METHODS: A retrieval was performed for the literature about the manufacturing methods of soft tissue scaffolds using key words of “additive manufacturing, microfabrication, vascular tissue engineering, muscle tissue engineering, cartilage tissue engineering, stereolithography, 3D printing, biodegradable hydrogel” in English and Chinese, which were published between January 2010 and September 2013 in PubMed Database and China National Knowledge Infrastructure (CNKI) Database.
RESULTS AND CONCLUSION:For large soft tissue defects repairing, structure design of the scaffolds has been shifted from a simple planar structure to a more complex three-dimensional structure, and integration of scaffold structure, materials and cels, and growth factors during the manufacturing procedure can be used to obtain the resolution of vascularization. Additive manufacturings become one of the most promising approaches for the ideal soft tissue scaffolds with gradient and complex structure and multi-materials. In particular, the hydrogel/cellcomposite scaffolds fabrication, a hot but promising approach to develop the soft tissue engineering wil be made progress by the accurate principles and processes of the hydrogel additive manufacturing combined with the introduction of living cels and growth factors.

Purpose　To study the main points of the diagnosis and differential diagnosis of the lymphadenitis in CSD. Methods　Expression of CD45, CD3 and CD68 were evaluated immunohistochemically (S-P method). Results　Five cases of microabscess in early stage and 21 cases of microabscess-granuloma were found. The histologic features were the formation of microabscess and granuloma. The early microabscess in the lymphnodes were surounded by B lymphocytes (CD20+) and macrophages (CD68+). The typial microabscess granuloma were surrounded by epitheloid cells (CD68+) and CD3 positive T lymphocytes. Conclusion　The main characteristic of the lymphadenitis of cat scratch disease is the formation of granuloma with microabscess. The immumohistochemical markers are useful to distinguish the proliferative cell types. This lesion may result from bacterial infection which induces the cell immune reaction.