PubMed Health⌕ Search

SEARCH · PubMed Health

Results for “Prostheses and Implants”

Explore indexed PubMed citations for clinical trials, systematic reviews and public health research. Read source abstracts and follow each citation to its original PubMed record.

Quote a phrase for an exact phrase match. Source license links do not imply unrestricted reuse.

At least 37 records · Page 2Linked to original sources
PubMed1988

Stability of performances of vascular prostheses retrospective study of 22 cases of human implanted prostheses.

Twenty-two cases of vascular graft failures (thrombosis, pseudoaneurysm, dilation, infection) were investigated by means of physicochemical, histological, and ultrastructural studies. A general decrease of mechanical resistance to stress of the prostheses was observed. Its magnitude ranged from 2 to 75% of the values of identical virgin prostheses and there was no relation with the duration of implantation. In addition to the breakage of yarn filaments (SEM), migration of fiber debris (histology) was observed in 7 cases. The structure of the polyester molecule had evolved after implantation. A decrease of crystallinity (x-ray diffraction and differential scanning calorimetry) was noted. These observations raise the question of the established stability of vascular prostheses and emphasize the need for further investigations in human graft retrieval programs.

Biocompatible Materials↗
PubMed1987

The formation of a neo-intima in textile prostheses implanted in the aorta of rats and dogs.

The formation of a neo-intima in textile prostheses implanted in the rat and dog aorta was studied by means of light- and scanning electron microscopy. Two independent cellular layers (the superficial and deep ingrowth layers) developed on the free surface and under the fibrin layer initially deposited on the inner surface of the prostheses. The superficial ingrowth layer invades the prosthesis from both the proximal and distal aortic stumps and extends over the primary fibrin layer, or replaces it. This layer consists mainly of smooth muscle cells of the triangular aortic type covered by endothelial-like cells. The deep ingrowth layer originates from cellular elements of the prosthetic bed. Fibroblasts, myofibroblasts and spindle-shaped smooth muscle cells invade the fibrin layer through the interstices of the fabric structure of the prosthesis. Precursors of endothelial cells, however, are absent from this population. The superficial and the deep ingrowth layers may become joined by progressive replacement of the fibrin layer, but remain distinguishable because of their different cellular components. When a continuous cellular layer is established on the inner surface of the prosthesis, and this is then covered by endothelial-like cells, the neo-intima formed remains stable during long-term studies.

Animals↗
PubMed1988

Implant prostheses for convertibility, stress control, esthetics, and hygiene.

A method of connecting "fixed partial denture" prostheses to osseointegrated implant fixtures has been described. The advantages of this system of restoration for partially and fully edentulous mouths are that it is more effective in addressing the problems of (1) stress-control on abutments, (2) a back-up system for abutment failures, (3) esthetics, and (4) control of bacterial plaques around abutments. To accomplish this procedure, the application of convertible periodontal prosthesis techniques with modifications to some existing implant systems is undertaken. The disadvantages of this method seem insignificant when one considers the complexities and risks involved with the present array of implant prosthesis alternatives. Some patients and dentists might consider the necessity of the prosthesis being detachable as one disadvantage. In reality, the prosthesis can be used as a fixed restoration until the patient has fully adapted to the new proprioception and appearance. A large percentage of patients feel uncomfortable with the word "removable" because it immediately creates a perception of unsightly metallic clasp display, palatal coverage, tongue interference, and negative body image. The use of the term "detachable" coupled with the doctor's offer to perform this task for the patient "whenever necessary" will usually relieve the patient's anxiety and allow the treatment to proceed. Once neuromuscular and esthetic adaptation have occurred and the patient has accepted the prosthesis, daily detaching and home-care hygiene by the patient will follow without incident. Esthetic improvement is obvious (Fig. 3).

Cementation↗
PubMed1993

Providing optimum torque to implant prostheses: a pilot study.

Ten N/cm torque has been proposed as the optimum level for the tightening of implant retaining gold screws in order to preload the implant components to limit loosening and fracture. The purpose of this study was to determine the influence of instrumentation and operator experience on the torque generated during manual tightening of slotted gold screws. Sixteen subjects, divided into four groups based on experience, were instructed to tighten five screws into implant analogs with 20-mm and 37-mm slotted screwdrivers. The screws were then removed with a torque gauge. All of the groups of subjects were able to generate significantly greater torque with the 37-mm screwdriver. Dentists with no implant treatment experience generated significantly less torque than the other three groups. Of the 12 dentist subjects, only 3 generated the optimal amount of torque when using the 20-mm screwdriver. Operators who had little experience dealing with implant prostheses were not able to provide the recommended torque and experienced operators tended to generate more than the recommended amount. None of the subjects were able to generate consistent torque values.

Analysis of Variance↗
PubMed1993

Minimizing biomechanical overload in implant prostheses: a computerized aid to design.

Implant-supported prostheses must be able to withstand the load capabilities of individual patients to overload them. The gold alloy screw in the Brånemark system is by intention the weakest component. Therefore, if cantilever lengths can be designed so that occlusal forces distributed to individual fixtures are limited to the gold screws' ability to accept them, breakage-free performance may be assured. Models, such as that of Skalak, are capable of developing the required analytical processes to provide the information necessary to achieve this design. Unfortunately, the overt mathematical complexity of the Skalak model has militated against its routine use in the operatory. Its computational aspects are, however, eminently suited to computerization and indeed provide the basis for the computer program that is described in this article. This program is simple to apply clinically and, when used in conjunction with available load parameters of gold screw performance, can provide the clinician with a routine and scientific basis for rational implant prosthesis design.

Bite Force↗
PubMed1991

Precision attachment-retained gingival veneers for fixed implant prostheses.

Parel et al. described a gingival veneer to provide additional support to the lower lip for patients with fixed implant prostheses. This article provides an alternate method that incorporates a precision attachment for increased support and retention of the gingival veneer. The procedure involves early recognition of the need for additional support and incorporation of an attachment into the definitive prosthesis framework.

Dental Implantation, Endosseous↗
PubMedDate not supplied

A review of clinical and technical considerations for fixed and removable implant prostheses in the edentulous mandible.

PURPOSE: The aim of the present article is to review some of the technical treatment options for implant prostheses restoring the edentulous mandible, mainly based on the Brånemark system. MATERIALS AND METHODS: Clinical and technical aspects are discussed for the three established concepts: (1) implant-supported fixed prosthesis, (2) removable implant-supported overdenture, and (3) combined implant-retained and soft tissue-supported overdenture prosthesis. RESULTS: The framework of an implant-supported fixed screw-retained prosthesis can be processed in gold, Co-Cr alloy, or titanium with casting, laser-welding, or milling techniques. To improve the stability and retention of a conventional complete denture, one to four implants are indicated, and unsplinted (single attachments) or splinted designs (bar systems) can be applied. The design of the overdenture prosthesis must be carefully planned according to the requirements to ensure adequate stability and optimal form, contour, and esthetics, and the patient's best comfort. CONCLUSION: A large variety of different treatment modalities exist for both the fixed and removable mandibular implant prosthesis. Clinical and technical aspects should be considered at the beginning of the treatment to: (1) select the optimal implant position, (2) establish an adequate number of functional units, (3) select the appropriate retainers, and (4) apply the best technique for framework processing and veneering.

Dental Alloys↗
PubMed1988

Fate of polyester arterial prostheses implanted as thoraco-abdominal by-passes in dogs: haematology, pathology, and biochemistry.

This study was designed to evaluate the haematological, pathological and biochemical characteristics of the flow surface in polyester arterial prostheses. Their implantations as thoraco-abdominal by-passes in dogs were scheduled to remain in place for periods ranging from four hours to six months. The haematologic parameters of the hosts were evaluated before implanting the prostheses and before harvesting the graft. To quantify the thrombogenicity of the flow surface, the platelet deposition and fibrinogen uptake were measured by means of an isotopic technique involving Indium-III labelled platelets and iodine-125 labelled fibrinogen. Synthesis of prostacyclin (PGI2) and thromboxane (TXA2) by the internal capsulae was determined by radioimmunoassay. The pathology was assessed according to previously described protocols. The haematologic parameters of the hosts did not alter substantially in the presence of the prostheses. The observed changes, though slight, were not pathologically significant 48 hours after implantation. Platelet and fibrin deposition was highest on the luminal surface of the prostheses 24 hours post-implantation. These decreased and became negligible after one month when the flow surface became smooth and glistening. The PGI2/TXA2 ratio of the luminal surface was much lower than that observed in native aortic tissue. These results show that the large calibre Dacron vascular prosthesis has a flow surface with a low degree of blood compatibility. The concentration of PGI2 on the newly-formed luminal surface remained low. This characteristic and the incomplete endothelialization of the luminal surface might be among the main factors that determine the high failure rate of synthetic prostheses when used as small diameter blood conduits.

6-Ketoprostaglandin F1 alpha↗
PubMed2006

Measuring chewing ability in randomized controlled trials with edentulous populations wearing implant prostheses.

In this article, the authors review methods commonly used to measure the masticatory ability of patients wearing conventional and implant prostheses. Measurement approaches are viewed in two broad categories: laboratory based and patient based. The laboratory based measures discussed are mastication time, particle size, force measurements, patterns of jaw movement and electromyographic (EMG) bursts and total EMG activity. Patient based measures include satisfaction and chewing difficulty. Oral health-related quality of life measures and diet/nutrition variables are briefly mentioned. Patient-based outcomes are recommended as the most appropriate variables of masticatory efficiency.

Bite Force↗
PubMed1996

Similarity in behavior of polytetrafluoroethylene (ePTFE) prostheses implanted into different interfaces.

The biomaterial ePTFE is widely used in the clinical environment for vascular replacement or bypass, as well as in the repair of tissue defects, especially those involving the abdominal wall. The objective of this study was to evaluate the healing response to ePTFE prostheses implanted into a circulatory interface and a tissue interface, each in a different animal species. For vascular implants, the Sprague-Dawley rat (n = 60) was used, while the New Zealand white rabbit (n = 20) was used in the tissue replacement model. In the former, a vascular microprosthesis measuring 5 mm in length and 1 mm in internal diameter, having a porosity of 30 microns, was implanted into the common iliac artery. In the rabbit, a 7 x 5-cm fragment of ePTFE (Soft-Tissue Patch) was implanted into a defect in anterior abdominal wall that involved all the tissue layers. In this case, the prosthesis was left touching the intestinal loops. The implants were studied between 14 and 90 days of postimplantation by means of light microscopy, scanning electron microscopy, and immunohistochemistry. The latter involved the use of anti-rat (MAC-341) and anti-rabbit (RAM-11) macrophage-specific monoclonal antibodies. The behavior of the ePTFE in the different interfaces (vascular and abdominal wall) was similar with respect to the following aspects: the prosthesis presented a process of encapsulation which was more intense on the outer surface; colonization of the implant was limited to the outermost two thirds, with minimal invasion of the middle portion; colonization was absent on the edges of the prosthesis; collagenization of the interstice of the mesh occurred late; the foreign body reaction taking place on the outer surface was similar in both interfaces, with formation of a barrier consisting of macrophages and giant cells that did not penetrate the prosthesis; and, finally, in neither of the two models was vascular colonization of the PTFE prosthesis observed; rather, the angiogenic process was limited to the periprosthetic zones. The integration of the implant made of ePTFE is similar despite the differences in interfaces and the use of different animal species. The macrophage response does not determine the success or failure of the implant.

Abdominal Muscles↗
PubMed2005

The use of three different matrices to ensure proper spatial dimension in fabricating definitive implant-supported prostheses.

Implant concepts continue to evolve not only in terms of materials, surfaces, and designs but also in clinical experience and technical management. This article presents a clinical and laboratory procedure describing how to plan, ensure, and achieve proper spatial dimension in fabricating definitive implant-supported prostheses with the use of 3 different matrices. This will in turn aid in restoring the patient with a predictable outcome from the outset of the treatment.

Dental Implantation, Endosseous↗
PubMed2005

Consistency of implantation of a total knee arthroplasty with a non-image-based navigation system: a case-control study of 235 cases compared with 235 conventionally implanted prostheses.

The aim of the study was to assess the consistency of the non-image-based navigation system OrthoPilot, Aesculap, Tuttlingen, Germany, in total knee arthroplasty (TKA) implantation in 5 European centers. Two hundred thirty-five TKAs implanted with this navigation system were matched (according to severity of the preoperative coronal deformation and body mass index) to a historical control group of 235 TKAs implanted with a conventional technique. Consistency of implantation was studied on a 3-month postoperative radiological control with coronal long-leg and sagittal standard x-rays. The use of the OrthoPilot navigation system allowed a statistically significant improvement in the consistent placement of both tibial and femoral components. In accordance with current literature, survival of the navigated implanted prostheses is expected to be longer.

Adult↗
PubMed1984

Patency and neo-intima development in 10 cm-long microvascular polyurethane prostheses implanted into the rat aorta.

Microvascular fibrous polyurethane prostheses (inner diameter 1.5 mm, length 10 cm) were implanted in the abdominal aorta of rats. The prostheses were fixed in a loop. All rats (n = 37) were reoperated 6 weeks after implantation to verify the patency of the prostheses. Eight prostheses were obliterated from various causes. The remaining 29 prostheses were found to be patent 3 months after implantation, which gives a patency rate of 79%. Six weeks and 3 months after implantation 7 and 4 rats, respectively, with patent prostheses were sacrificed. The remaining 18 rats of this study are still alive, more than 4 months after implantation, and will be included in long-term observation studies. The prostheses were examined using both light and scanning electron microscopy. The patent prostheses exhibited macroscopically a clear and transparent inner surface. No obliterative processes could be found either macroscopically or microscopically. Neo-intima ingrowth had advanced +/- 10 mm into the prostheses over the anastomotic line from both ends 3 months after implantation, and was continued by a single endothelium layer for several centimeters. An acellular, stable fibrin film was found inbetween the cellular lining. The neo-intima was anchored at the prosthesis by cellular protrusions extending between the polyurethane fibers. Though 10 cm long prostheses were implanted under unfavorable hemodynamic conditions, a patency rate of 79% was achieved, both 6 weeks and 3 months after implantation. This patency rate could have been higher if evident technical failures had been avoided.(ABSTRACT TRUNCATED AT 250 WORDS)

Animals↗
PubMed2004

[Value of memory functions in implantable prostheses].

The development of memory functions with memorised electrogrammes is one of the most important technical advances in cardiac pacemakers and defibrillators. These memory functions are very useful in the management of patients with implanted prostheses. In the case of defibrillators, the memory allows evaluation and validation of appropriate treatments (shock or asymptomatic antitachycardia stimulation) or inappropriate function. The memory can also help assess the efficacy of complementary antiarrhythmic therapy or radiofrequency ablation. The incorporation of memory functions in pacemakers is more recent but no less useful. The latest generation of pacemakers have not only a therapeutic but also a diagnostic role with respect to atrial and ventricular arrhythmias. They can lead to the prescription of an antiarrhythmic or anticoagulant drug in cases of sustained atrial fibrillation confirmed by the memorised electrogrammes. The memory function is also a great aid in reprogramming stimulators in cases of overdetection (V-A cross talk). They may also be activated by the patient in cases of sporadic paroxysmal symptoms. The latest development is that of a purely diagnostic prosthesis: the implantable Holter, whose main indication is in the investigation of unexplained syncope.

Atrial Fibrillation↗
PubMed2003

Within-subject comparisons of maxillary fixed and removable implant prostheses: Patient satisfaction and choice of prosthesis.

Dental implants provide patients with restorative options for the edentulous maxilla. Both fixed and removable prostheses can be attached to the edentulous maxilla, but the efficacy of different designs has not been determined. In this two-session within-subject crossover trial we compared maxillary implant retained fixed prostheses with removable implant overdentures opposed by mandibular implant-supported overdentures. Sixteen patients, who had previously received mandibular implants, entered the study and received four to six maxillary implants. After dropouts as a consequence of a lack of osseointegration and general health problems, 13 remained. Of these, five received the removable prosthesis first and eight the fixed prosthesis. After 2 months, the prostheses were exchanged and the second was also worn for 2 months. Psychometric measurements of general satisfaction with the prostheses as well as comfort, ability to speak, stability, esthetics, ease of cleaning and occlusion were obtained once each prosthesis had been worn for 2 months. Chewing ability was assessed for seven types of food. Removable long-bar overdentures received significantly higher ratings of general satisfaction than fixed prostheses (P = 0.003). Patients also rated their ability to speak and ease of cleaning significantly better with the removable overdentures. Nine patients chose to keep the removable prosthesis and four preferred to keep the fixed prosthesis. The results suggest that maxillary removable overdentures on multiple implants may provide patients with better function than fixed prostheses.

Attitude to Health↗
PubMedDate not supplied

A method aimed at achieving passive fit in implant prostheses: case report.

PURPOSE: The aim of this article is to describe a technique that attempts to solve titanium-related problems while affording passive fit. MATERIALS AND METHODS: The method basically involves the manufacture of a cast titanium framework fitted onto titanium machined abutments. After verifying the passive fit of the framework presoldered to the abutments, Nd-YAG laser welding is completed in the laboratory. RESULTS: The aim of the technique is to secure the following clinical benefits: (1) use of titanium, as it is the best-suited material; (2) use of high-precision machined abutments; (3) laser welding and its advantages; and (4) achievement of passive fit. CONCLUSION: The technique described is adequate to achieve passive fit in implant prostheses using titanium and laser welding.

Acrylic Resins↗
PubMed1993

Healing of microvenous PTFE prostheses implanted into the rat femoral vein.

44 PTFE prostheses (Gore-Tex; ID 1 mm) were implanted into rats' femoral veins by means of the sleeve anastomotic technique and were evaluated at regular intervals from 1 h up till 24 weeks after implantation by means of light and electron microscopy to study in detail their healing process. All prostheses, except one at 1 week and one at 24 weeks after implantation, were patent at the time of removal. Upon implantation, the luminal surface of the prostheses became covered with a thin clot layer. From 1 week onwards, endothelial cells originating from the anastomotic sides grew in across the anastomoses. In addition, small capillary-like orifices were present at the anastomotic sites, from which endothelial cells also seemed to originate. At 2 weeks, in several areas in the mid-region of the prostheses, the fronts of regenerating endothelial cells had reached each other, and about 80% of the luminal surface was covered by endothelium and at 3 weeks, the prostheses were completely covered by an endothelial layer. These results demonstrate that PTFE microvenous prostheses heal exclusively by means of rapid ingrowth of endothelial cells originating from both sides at the anastomoses.

Animals↗