Rubber Prostheses

Cardiovascular Blood vessel prosthesis Heart valve Catheter Pacemaker Dacron, Teflon , polyurethane Reprocessed tissue, stainless steel, carbon Silicone rubber. Teflon, polyurethane Polyurethane, silicone rubber, platinum electrodes... 

An earlier study has Indicated the ability of parenteral prophylactic antibiotic therapy to reduce the Incidence of prosthetic mitral valve failure In dogs associated with valve related Infections. As an alternative to the above approach, we have Investigated the therapeutic efficacy of a system providing for a sustained release of gentamicin, Incorporating the antibiotic In silicone rubber which Is In the sewing rim of a mitral valve prosthesis Implanted In dogs. 

Dental Polymers. Every year nearly a half billion dental fillings are done, and over a million dentures are constructed. Most of the materials used in each of these cases are polymeric. In addition, over 300,000 dental implants are made each year with either ceramics or polymers (1). The majority of the dental fillings and dentures are made from various copolymers of methyl methacrylate with other acrylics, although some other polymers, such as polyurethanes, vinyl chloride-vinyl acetate-methacrylate copolymers, vulcanized rubber, and epoxies, have been used to some extent. One major problem is aesthetics—the prosthesis must look natural and not discolor (by photoinduction or staining) to any great extent. 

The best-known example of this application is the mammary prosthesis, or replacement breast, which consists of a silicone rubber gel in a bag of silicone that has been preformed to match the contours of a natural breast after implantation. The replacement testicle uses the same basic materials in a different shape. Neither device performs any physiological function (1, 12). 

The in vivo and jji vitro pressure measurements indicate that like other ball valves, due to its centrally occluding design, the Starr-Edwards ball valves are moderately stenotic in the medium to larger sizes. In the smaller sizes the valves are very stenotic. Patients with this prosthesis would not be able to lead very strenuous life styles. The prosthesis does have low regurgitant volumes, the lowest among mechanical prostheses in current clinical use. The in vivo and in vitro data seem to indicate that the instability of the silicone rubber poppet (1200/1260, 6120) could lead to larger pressure drops across the prosthesis. 

Finger joint replacements are divided into three types (1) hinge, (2) polycentric, and (c) space-fiUer. The most widely used are the space-filler type. These are made of high performance silicone rubber (polydimethylsiloxane) and are stabilized with a passive fixation method. This method depends on the development of a thin, fibrous membrane between implant and bone, which allows pistoning of the prosthesis. This fixation can provide only minimal rigidity of the joint [Swanson, 1973). Implant wear and cold flow associated with erosive cystic changes of adjacent bone have been reported with silicone implants [Carteret al., 1986 MaistrelU, 1994]. 

I. Rotaru, C. Bujoreanu, A. Bele, M. Cazacu, D. Olaru, Experimental testing on free vibration behaviour for silicone rubbers proposed within lumbar disc prosthesis. Materials Science and Engineering C, ISSN 0928-4931 42 (September 1, 2014) 192-198. http //dx.doi.Org/10.1016/j.msec.2014.05.021. 

The circulatory fluid is ejected by an electropneumatically driven ventricular pump. Downstream of the pump, an aortic valve assembly is located two different models have been built in order to offer lateral or frontal view of the prosthesis movements. Suitable stent adapters allow to test prostheses of different type and size. The aorta is a variable compliance rubber tube. Through a rigid conduit the fluid is conveyed to the laminar flow assembly which controls peripheral resistances. Aortic compliance and peripheral resistances are hydropneumatically controlled. The fluid, passing through a venous reservoir open to atmospheric pressure, reaches the left atrium. This is a rigid wall chamber in which a hydropneumatic system relates cardiac output to venous return, reproducing Frank--Starling s Law. Between atrium and ventricle there is another valve test assembly which allows to test mitral valves. 

Rods of silicone rubber of semi-rigid and malleable penile prosthesis present at ultrasound as echo-poor structures within the corpora cavernosa (Basu et al. 2002). The central metal core of malleable prostheses appears as an echogenic structure with a characteristic comet-tail artifact. 

Tracheal prosthesis (tracheal stent) of silicone rubber [11] ... 

Another is the combination of the same femoral component and conductive silicone rubber tibial flat specimen( E = 9.1 MPa, 3 mm in thickness) supported by acrylic flat plate. The latter model corresponds to the knee prosthesis with compliant artificial cartilage. 

Schaff NG. (1970) Color characterizing silicone rubber facial prosthesis. 1 Prosthet Dent 24 198-202... 

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