Papers by Keyword: Soft Tissue

Abstract: In this study, a synthetic scaffold was prepared from polycaprolactone (PCL) and polyurethane (PU) blend, in a ratio of [2:1] [PCL: PU], using electrospinning technique. Electrospun scaffolds from native PCL and PU were also prepared for comparison, using the same polymer concentration 15% weight/ volume w/v. The detailed microstructure and other properties, like mechanical properties, porosity, and contact angle were investigated and compared between the three prepared scaffolds. Then, the survival, adhesion, proliferation and penetration of rat embryonic fibroblast (REF) cells were evaluated on these three prepared scaffolds after being in vitro cultured with these cells for 21 days, using scanning electron microscope (SEM) analysis and histological analysis. The results showed that, all the studied properties, including mechanical properties and contact angle were enhanced by combining PU with PCL in the [PCL: PU] scaffold. The average diameter of fiber and the average size of pore were suitable and proper for cell attachment, cell proliferation, and also the big average pore size in [PCL: PU] scaffold was enough for cell penetration to form a three- dimension 3-D structure, which is the aim of this study.

Abstract: This paper presents some aspects from last 10 years of experience, when we used the hyaluronic acid produced and traded by a certain company, to obtain aesthetic good results in the treatment of the facial wrinkles, nazolabial folds, augmentation of the lips, face rejuvenation and hydration, correction of soft tissues deficiencies after major surgical operations.

Abstract: In this article we intend to make an overview on the forces and deformations arising on the mandible and to study how the soft parts of the face are deformed, using an analysis of the influence of mechanical stresses using a finite element computer program. Thus, from the engineering point of view we propose a validation of medical results with an overview about the directions of deformation of the bones and soft parts due to normal growth of individuals. For this purpose we have used a 2D finite element static analysis of the mandible and soft tissue.

Abstract: Three-dimensional 3D modeling, surgery simulation and face prediction of the maxillofacial soft and hard tissue has a great significance for the study of facial growth and development, diagnosis and treatment of facial deformity and postoperative face prediction and treatment evaluation. Based on maxillofacial 3D modeling and measurement analysis, real-time variable model is set up. In virtual environment, image feedback, force and tactile perception in combined together surgical simulation. Furthermore, the system of surgical prediction and postoperative results display is proposed, which has great value and clinical significance.

Abstract: Different methods are available for fixation on the femoral side of a quadruple soft tissue autograft in anterior cruciate ligament reconstruction and the best method is still to be found. There are also a large number of polymers in current practice, with a trend towards ceramic composites, required for better bone formation around the implant. If ceramic – polymer composites have better bioactive properties can be demonstrated only by long term in vivo follow up. Several methods of trans-femoral fixation are currently in use in our clinic – two of them being compared in this study: Rigidfix (Mitek DePuy Westwood, MA) and Biosteon (Stryker). First system produces a very stiff fixation using two implant pins made of poly-L-lactic acid (PLLA); the second technique is using a large composite (25% hydroxyapatite and 75% PLLA) suspension system with the mechanical advantage of achieving a “ press-fit” graft fixation in the tunnel. We prospectively follow our cases with clinical visits at 1, 3, 6 and 12 months – for research purposes, in a series of 20 cases (10 from each group) MRI (Siemens, 1,5 Tesla) were performed at same time intervals. Volume loss of the implant, tunnel enlargement, presence of osteolysis, fluid lines, edema and postoperative pin replacement by bone tissue were evaluated. There was no edema or signs of inflammation around the bone tunnels at more than 24 months of folllow-up. Several of the Biosteon sites were surrounded by an area of increased signal on the fat-suppressed images. At 12 months, the femoral implants showed an average volume loss of 80% (±10%) P\0.05), respectively. At 3, 6, and 12 months volume losses range from 5 % (±2%), 29% (±19%) and 89% (±7%) for the composite implant. The femoral tunnel enlargement was less than 50% of the original bone tunnel volume after 12 months. Bone ingrowth was observed in all patients. Use of a composite ceramic – polymer bioabsorbable material (enhanced to form bone) will be easily incorporated by the body, retain strength for an adequate period of time, obviate the need for secondary procedures such as hardware removal, and facilitate revision surgery.

Abstract: In the virtual scene of robot assisted virtual surgery simulation system, the surgical instruments achieve complex motion following the haptic devices and the soft tissue deforms continuously under interaction forces. In order to meet the rapidity of collision detection, an algorithm based on changeable direction hull bounding volume hierarchy is proposed. Strategy of combining surface model with body model is developed for soft tissue deformation. Skeleton sphere model of soft tissue is built. Deformation can be achieved based on mass-spring theory after matching collision information with the skeleton sphere model. The experiments show that the proposed collision detection method implements faster speed compared with fixed direction hull algorithm and soft tissue deforms through combination of collision information with sphere model.

Abstract: At the neck area of dental implant surface, machined surface (Ms) has been employed to avoid surface contamination. Recently, implants which have roughened surface texture (Rs) at their neck are also available. However, from the viewpoint of soft tissue integration, it remains to be elucidated whether or not surface topography affects the soft tissue attachment around implants. The aim of the present study was to clarify the influence of surface topography on peri-implant soft tissue integration. First, surface roughness of both surfaces was measured. Second, protein adsorption capability on both surfaces was examined. Then, as the rat implant model, titanium implants with each surface were inserted into the maxillae. Horseradish peroxidase (HRP) tracer was applied 4 weeks post implantation to the gingival sulci of implants or natural teeth (NT) to investigate the sealing capability of periodontal/peri-implant soft tissue. Collagen density was also observed by fluorescent staining. As a result, surface roughness (Sa) of Ms and Rs was 0.16 µm and 0.25 µm, respectively. Protein adsorption capability on both surface showed no significant differences. In the NT group of the rat implant model, presence of HRP was restricted only in the coronal portion of epithelium. In both implant groups, in contrast, more invasion of HRP was observed in the soft tissue around implants. Especially in the Ms group, more HRP was observed in the deeper area compared with Rs group. Stronger expression of collagen was observed around Rs compared to Ms at the connective tissue-implant interface. It could be speculated that, with dense collagen, Rs implants showed stronger soft tissue integration compared with Ms implants, but the integration is not as strong as NT’s.

Abstract: The purpose of this study is to investigate the effects of two kinds of total contact insoles (TCI). Traditional TCI reflects the shape of foot, while deformed total contact insole(DTCI) was established basing on the shape of footprints on clay prototypes. A female experimenter was asked to exert different loadings on clay prototypes to make footprints. Shapes of the footprints have been recorded by a reverse engineering method. Force distribution results in given preconditions were reflected and recorded for quantified comparison. shapes of two total contact insoles were rebuilt under different loadings. Having deformation of different magnitude over each area as a reference, effect and possibility of further improvement have been explored. Our findings showed that insoles based on larger deformation can be utilized to redistribute peak pressure effectively under normal loading. The results indicates that DTCI in this study can be used as a more important tool in adjusting functions or comfort ratings of shoes.

Abstract: An orthogonal cutting model for investigating indentation type cutting of soft tissue was established, and the cutting force model was constructed theoretically based on fracture mechanics. A planar biological soft tissue cutting experimental setup was designed and developed to realize soft tissue cutting. Cutting experiments using orthogonal cutting blades were performed on fresh porcine liver at different cutting speeds. It was experimentally shown that the cutting speeds and the blade rake angles have significant effects on the penetration force and cutting force. Finally, a regression equation was obtained to explain the relationship among cutting force, cutting speed, and rake angle. These findings provide new insight into the biological soft tissue cutting.

Abstract: Biopsy precious research has an important relationship with treatment efficiency and side effect complication. Most of the investigation is focus on the non-creatural material which is used to substitute creatural soft tissue for precious research. The aim of this paper is to develop a prescription that can be used for opaque and transparent PVA making which has similar mechanics property to the creatural tissue. The preparation, characteristics, and the results of PVA hydrogel on the composite material are studied as the key investigation. Porcine liver tissue property is also tested as a consultant for PVA material preparation. Comparing with the liver tissue test result, certain component ratio and freezing-thaw circle are determined. This PVA hydrogel material shows big potential in the creatural material substitution application. This research will benefit others who are interested in using non-creatural material to do experiment or surgical technology training.