scholarly journals CAMM Techniques for the Prediction of the Mechanical Properties of Tendons and Ligaments Nanostructures

2005 ◽  
Vol 5 ◽  
pp. 564-570
Author(s):  
Simone Vesentini ◽  
Franco M. Montevecchi ◽  
Alberto Redaelli

Theoretical prediction of the mechanical properties of soft tissues usually relies on a top-down approach; that is analysis is gradually refined to observe smaller structures and properties until technical limits are reached. Computer-Assisted Molecular Modeling (CAMM) allows for the reversal of this approach and the performance of bottom-up modeling instead. The wealth of available sequences and structures provides an enormous database for computational efforts to predict structures, simulate docking and folding processes, simulate molecular interactions, and understand them in quantitative energetic terms. Tendons and ligaments can be considered an ideal arena due to their well defined and highly organized architecture which involves not only the main structural constituent, the collagen molecule, but also other important molecular “actors” such as proteoglycans and glycosaminoglycans. In this ideal arena each structure is well organized and recognizable, and using the molecular modeling tool it is possible to evaluate their mutual interactions and to characterize their mechanical function. Knowledge of these relationships can be useful in understanding connective tissue performance as a result of the cooperation and mutual interaction between different biological structures at the nanoscale.

Symmetry ◽  
2021 ◽  
Vol 13 (7) ◽  
pp. 1126
Author(s):  
Giovanna Iezzi ◽  
Francesca Di Lillo ◽  
Michele Furlani ◽  
Marco Degidi ◽  
Adriano Piattelli ◽  
...  

Symmetric and well-organized connective tissues around the longitudinal implant axis were hypothesized to decrease early bone resorption by reducing inflammatory cell infiltration. Previous studies that referred to the connective tissue around implant and abutments were based on two-dimensional investigations; however, only advanced three-dimensional characterizations could evidence the organization of connective tissue microarchitecture in the attempt of finding new strategies to reduce inflammatory cell infiltration. We retrieved three implants with a cone morse implant–abutment connection from patients; they were investigated by high-resolution X-ray phase-contrast microtomography, cross-linking the obtained information with histologic results. We observed transverse and longitudinal orientated collagen bundles intertwining with each other. In the longitudinal planes, it was observed that the closer the fiber bundles were to the implant, the more symmetric and regular their course was. The transverse bundles of collagen fibers were observed as semicircular, intersecting in the lamina propria of the mucosa and ending in the oral epithelium. No collagen fibers were found radial to the implant surface. This intertwining three-dimensional pattern seems to favor the stabilization of the soft tissues around the implants, preventing inflammatory cell apical migration and, consequently, preventing bone resorption and implant failure. This fact, according to the authors’ best knowledge, has never been reported in the literature and might be due to the physical forces acting on fibroblasts and on the collagen produced by the fibroblasts themselves, in areas close to the implant and to the symmetric geometry of the implant itself.


1999 ◽  
Vol 9 (3) ◽  
pp. 259-266 ◽  
Author(s):  
OLIVIER CHAVANON ◽  
CATHERINE BARBE ◽  
JOCELYNE TROCCAZ ◽  
LIONEL CARRAT ◽  
CHRISTOPHE RIBUOT ◽  
...  

Author(s):  
Donna M. Ebenstein

Nanoindentation is becoming an increasingly popular tool in the biomaterials field due to its ability to measure local mechanical properties in small, irregularly-shaped or heterogeneous samples.1 Although this technique was readily adapted to the study of mineralized tissues, the application of nanoindentation to compliant, hydrated biomaterials such as soft tissues and hydrogels has led to many challenges.1 Three key concerns associated with nanoindentation of compliant, hydrated materials are inaccurate surface detection, errors due to adhesion forces, and fluid interactions with the tip.1–4


Author(s):  
David E. Alexander ◽  
Kenneth L. Ratzlaff ◽  
Ricardo J. Roggero ◽  
Jennifer S.-Y. Hsieh

2008 ◽  
Vol 396-398 ◽  
pp. 7-10 ◽  
Author(s):  
Ana Maria Minarelli Gaspar ◽  
Sybele Saska ◽  
R. García Carrodeguas ◽  
A.H. De Aza ◽  
P. Pena ◽  
...  

The biological response following subcutaneous and bone implantation of β-wollastonite(β-W)-doped α-tricalcium phosphate bioceramics in rats was evaluated. Tested materials were: tricalcium phosphate (TCP), consisting of a mixture of α- and β-polymorphs; TCP doped with 5 wt. % of β-W (TCP5W), composed of α-TCP as only crystalline phase; and TCP doped with 15 wt. % of β-W (TCP15), containing crystalline α-TCP and β-W. Cylinders of 2x1 mm were implanted in tibiae and backs of adult male Rattus norvegicus, Holtzman rats. After 7, 30 and 120 days, animals were sacrificed and the tissue blocks containing the implants were excised, fixed and processed for histological examination. TCP, TCP5W and TCP15W implants were biocompatible but neither bioactive nor biodegradable in rat subcutaneous tissue. They were not osteoinductive in connective tissue either. However, in rat bone tissue β-W-doped α-TCP implants (TCP5W and TCP15W) were bioactive, biodegradable and osteoconductive. The rates of biodegradation and new bone formation observed for TCP5W and TCP15W implants in rat bone tissue were greater than for non-doped TCP.


2021 ◽  
Vol 26 (2) ◽  
pp. 150-157
Author(s):  
R. R. Farkhshatova ◽  
L. P. Gerasimova ◽  
I. T. Yunusov

Relevance. It is currently relevant to study and compare the effectiveness of the autologous connective tissue grafts and the combination of collagen-based and autologous platelet-rich plasma in the surgical treatment of Miller Class I gingival recessions.Materials and methods. We examined and treated 48 (20 male (41.67%) and 28 female (58.33%)) patients aged from 25 to 40 years with Miller Class I gingival recessions. All gingival recessions were treated surgically using a modified twolayer tunnel technique. The patients were divided into two groups according to the graft type. Group I (24 patients (50%) had a connective tissue graft from the hard palate. Group II (24 patients (50%) used the combination of the autologous platelet-rich plasma and 3D collagen matrix Fibromatrix for the regeneration of oral soft tissues. We removed the sutures on the 14th day. The patients were followed up on the 7th and 14th days and in 1.3 months.Results. 48 Miller Class I gingival recessions were treated between 2018 and 2020. The depth of gingival recessions averaged 3.5 ± 1.13 mm before treatment. The level of the attached keratinized gingiva regarding the cementoenamel junction significantly (p < 0.001) improved in both groups after the surgery. The width and thickness of the keratinized gingiva best increased in group II. The mean effectiveness of gingival recession treatment was 84% in study group I and 96% – in study group II. Pain syndrome, fibrinous plaque and soft tissue edema were insignificant in group II.Conclusion. The combination of the autologous platelet-rich plasma and Fibromatrix, collagen 3D matrix, for the regeneration of the oral soft tissues is a more effective technique for the treatment of Miller Class I gingival recessions. This technique has several advantages. It is minimally invasive, less painful, soft tissue postoperative swelling is less and the received volume of the attached keratinized gums is larger than with a connective tissue graft. 


2021 ◽  
Author(s):  
SAGAR PATIL ◽  
MICHAEL OLAYA ◽  
PRATHAMESH DESHPANDE ◽  
MARIANNA MAIARÙ ◽  
GREGORY ODEGARD

This article details the molecular modeling of full and off-stoichiometry models of the DGEBF/DETDA epoxy system using Molecular Dynamics to predict the mechanical properties as a function of the crosslinking density. The Reactive Interface Force Field (IFF-R) is implemented in this work to simulate mechanical deformation. The “fix bond/react” command in LAMMPS is used to simulate crosslinking between epoxy monomers. The results show that the predicted mass density, volumetric shrinkage, and bulk modulus have a strong dependence on the stoichiometry of the epoxy.


2013 ◽  
Vol 20 (4) ◽  
pp. 343-350 ◽  
Author(s):  
Pandian Amuthakkannan ◽  
Vairavan Manikandan ◽  
Jebbas Thangaiah Winowlin Jappes ◽  
Marimuthu Uthayakumar

AbstractMechanical properties of fiber reinforcement that can be obtained by the introduction of basalt fibers in jute fiber-reinforced polyester composites have been analyzed experimentally. Basalt/jute fiber-reinforced hybrid polymer composites were fabricated with a varying fiber percentage by using compression molding techniques. The fabricated composite plates were subjected to mechanical testing to estimate tensile strength, flexural strength and impact strength of the composites. The effect of fiber content on basalt/jute fiber in the composites has been studied. Addition of jute fiber into basalt fiber composite makes it a cost-effective one. Incorporation of basalt fiber into the composites was at approximately 10%, 20%, up to 90%, and the jute fiber percentage was reduced from 90%, 80%, to 10% correspondingly. Mechanical properties were investigated as per ASTM standards. Tensile and flexural strengths were tested by using a computer-assisted universal testing machine, and impact strength by using an Izod impact tester. It has been observed that the addition of jute fiber to the basalt fiber polyester composites enhanced the mechanical properties. Water absorption of hybrid composites was also analyzed and was found to be proportional to fiber percentage.


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