scholarly journals Microarchitecture of titanium cylinders obtained by additive manufacturing does not influence osseointegration in the sheep

2021 ◽  
Vol 8 (4) ◽  
Author(s):  
Louis Rony ◽  
Eric Aguado ◽  
Bruno Verlee ◽  
Florence Pascaretti-Grizon ◽  
Daniel Chappard
Keyword(s):  
Additive Manufacturing ◽  
Bone Cells ◽  
Porous Metal ◽  
Mechanical Resistance ◽  
Metallic Foams ◽  
Trabecular Microarchitecture ◽  
Natural Bone ◽  
The Core ◽  
Large Bone ◽  
Large Bone Defects

Abstract Large bone defects are a challenge for orthopedic surgery. Natural (bone grafts) and synthetic biomaterials have been proposed but several problems arise such as biomechanical resistance or viral/bacterial safety. The use of metallic foams could be a solution to improve mechanical resistance and promote osseointegration of large porous metal devices. Titanium cylinders have been prepared by additive manufacturing (3D printing/rapid prototyping) with a geometric or trabecular microarchitecture. They were implanted in the femoral condyles of aged ewes; the animals were left in stabling for 90 and 270 days. A double calcein labeling was done before sacrifice; bones were analyzed by histomorphometry. Neither bone volume, bone/titanium interface nor mineralization rate were influenced by the cylinder’s microarchitecture; the morphometric parameters did not significantly increase over time. Bone anchoring occurred on the margins of the cylinders and some trabeculae extended in the core of the cylinders but the amount of bone inside the cylinders remained low. The rigid titanium cylinders preserved bone cells from strains in the core of the cylinders. Additive manufacturing is an interesting tool to prepare 3D metallic scaffolds, but microarchitecture does not seem as crucial as expected and anchoring seems limited to the first millimeters of the graft.

scholarly journals Vascularization of Nanohydroxyapatite/Collagen/Poly(L-lactic acid) Composites by Implanting Intramuscularly In Vivo

2014 ◽  
Vol 2014 ◽  
pp. 1-5 ◽  
Author(s):  
Hai Wang ◽  
Xiao Chang ◽  
Guixing Qiu ◽  
Fuzhai Cui ◽  
Xisheng Weng ◽  
...  
Keyword(s):  
Lactic Acid ◽  
Orthopaedic Surgery ◽  
Bone Substitutes ◽  
Bone Defects ◽  
Large Defect ◽  
Natural Bone ◽  
Composition And Structure ◽  
Large Bone ◽  
Large Bone Defects

It still remains a major challenge to repair large bone defects in the orthopaedic surgery. In previous studies, a nanohydroxyapatite/collagen/poly(L-lactic acid) (nHAC/PLA) composite, similar to natural bone in both composition and structure, has been prepared. It could repair small sized bone defects, but they were restricted to repair a large defect due to the lack of oxygen and nutrition supply for cell survival without vascularization. The aim of the present study was to investigate whether nHAC/PLA composites could be vascularized in vivo. Composites were implanted intramuscularly in the groins of rabbits for 2, 6, or 10 weeks (n=5×3). After removing, the macroscopic results showed that there were lots of rich blood supply tissues embracing the composites, and the volumes of tissue were increasing as time goes on. In microscopic views, blood vessels and vascular sprouts could be observed, and microvessel density (MVD) of the composites trended to increase over time. It suggested that nHAC/PLA composites could be well vascularized by implanting in vivo. In the future, it would be possible to generate vascular pedicle bone substitutes with nHAC/PLA composites for grafting.

scholarly journals Factors related to large bone defects of bipolar lesions and a high number of instability episodes with anterior glenohumeral instability

2021 ◽  
Vol 16 (1) ◽  
Author(s):  
Noboru Matsumura ◽  
Kazuya Kaneda ◽  
Satoshi Oki ◽  
Hiroo Kimura ◽  
Taku Suzuki ◽  
...  
Keyword(s):  
Humeral Head ◽  
Glenohumeral Joint ◽  
Three Dimensional ◽  
Clinical Results ◽  
Bone Defects ◽  
Symptom Duration ◽  
Glenohumeral Instability ◽  
Explanatory Variables ◽  
Large Bone ◽  
Large Bone Defects

Abstract Background Significant bone defects are associated with poor clinical results after surgical stabilization in cases of glenohumeral instability. Although multiple factors are thought to adversely affect enlargement of bipolar bone loss and increased shoulder instability, these factors have not been sufficiently evaluated. The purpose of this study was to identify the factors related to greater bone defects and a higher number of instability episodes in patients with glenohumeral instability. Methods A total of 120 consecutive patients with symptomatic unilateral instability of the glenohumeral joint were retrospectively reviewed. Three-dimensional surface-rendered/registered models of bilateral glenoids and proximal humeri from computed tomography data were matched by software, and the volumes of bone defects identified in the glenoid and humeral head were assessed. After relationships between objective variables and explanatory variables were evaluated using bivariate analyses, factors related to large bone defects in the glenoid and humeral head and a high number of total instability episodes and self-irreducible dislocations greater than the respective 75th percentiles were evaluated using logistic regression analyses with significant variables on bivariate analyses. Results Larger humeral head defects (P < .001) and a higher number of total instability episodes (P = .032) were found to be factors related to large glenoid defects. On the other hand, male sex (P = .014), larger glenoid defects (P = .015), and larger number of self-irreducible dislocations (P = .027) were related to large humeral head bone defects. An increased number of total instability episodes was related to longer symptom duration (P = .001) and larger glenoid defects (P = .002), and an increased number of self-irreducible dislocations was related to larger humeral head defects (P = .007). Conclusions Whereas this study showed that bipolar lesions affect the amount of bone defects reciprocally, factors related to greater bone defects differed between the glenoid and the humeral head. Glenoid defects were related to the number of total instability episodes, whereas humeral head defects were related to the number of self-irreducible dislocations.

scholarly journals 3D Printed Masks for Powders and Viruses Safety Protection Using Food Grade Polymers: Empirical Tests

Polymers ◽  
2021 ◽  
Vol 13 (4) ◽  
pp. 617
Author(s):  
Ruben Foresti ◽  
Benedetta Ghezzi ◽  
Matteo Vettori ◽  
Lorenzo Bergonzi ◽  
Silvia Attolino ◽  
...  
Keyword(s):  
Surface Roughness ◽  
Additive Manufacturing ◽  
Material Selection ◽  
Mechanical Resistance ◽  
Biological Safety ◽  
Fused Deposition ◽  
Industrial Grade ◽  
Safety Protection ◽  
3D Printed ◽  
Manufacturing Technologies

The production of 3D printed safety protection devices (SPD) requires particular attention to the material selection and to the evaluation of mechanical resistance, biological safety and surface roughness related to the accumulation of bacteria and viruses. We explored the possibility to adopt additive manufacturing technologies for the production of respirator masks, responding to the sudden demand of SPDs caused by the emergency scenario of the pandemic spread of SARS-COV-2. In this study, we developed different prototypes of masks, exclusively applying basic additive manufacturing technologies like fused deposition modeling (FDM) and droplet-based precision extrusion deposition (db-PED) to common food packaging materials. We analyzed the resulting mechanical characteristics, biological safety (cell adhesion and viability), surface roughness and resistance to dissolution, before and after the cleaning and disinfection phases. We showed that masks 3D printed with home-grade printing equipment have similar performances compared to the industrial-grade ones, and furthermore we obtained a perfect face fit by customizing their shape. Finally, we developed novel approaches to the additive manufacturing post-processing phases essential to assure human safety in the production of 3D printed custom medical devices.

Permeability and strength of a porous metal structure fabricated by additive manufacturing

2015 ◽  
Vol 219 ◽  
pp. 10-16 ◽  
Author(s):  
Tatsuaki Furumoto ◽  
Ayato Koizumi ◽  
Mohd Rizal Alkahari ◽  
Rui Anayama ◽  
Akira Hosokawa ◽  
...  
Keyword(s):  
Additive Manufacturing ◽  
Porous Metal ◽  
Metal Structure

scholarly journals Tissue engineered vascularized periosteal flap enriched with MSC/EPCs for the treatment of large bone defects in rats

2017 ◽  
Vol 39 (4) ◽  
pp. 907-917 ◽  
Author(s):  
Christoph Nau ◽  
Dirk Henrich ◽  
Caroline Seebach ◽  
Katrin Schröder ◽  
John H. Barker ◽  
...  
Keyword(s):  
Bone Defects ◽  
Periosteal Flap ◽  
Large Bone ◽  
Large Bone Defects

Reconstruction of Large Bone Defects Using induced membrane Technique of Masquelet

2021 ◽  
Vol 0 (0) ◽  
pp. 0-0
Author(s):  
Mohammed soliman ◽  
Yousif Khira ◽  
.mohamed Elzoheiry ◽  
ahmad abdelwahab
Keyword(s):  
Bone Defects ◽  
Induced Membrane ◽  
Membrane Technique ◽  
Induced Membrane Technique ◽  
Large Bone ◽  
Large Bone Defects

Composite Scaffolds for Large Bone Defects

2019 ◽  
pp. 250-257
Author(s):  
Evangelos Daskalakis ◽  
Enes Aslan ◽  
Fengyuan Liu ◽  
Glen Cooper ◽  
Andrew Weightman ◽  
...  
Keyword(s):  
Bone Defects ◽  
Composite Scaffolds ◽  
Large Bone ◽  
Large Bone Defects
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