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At least 55 records · Page 3Linked to original sources

Conversion prosthesis: a transitional fixed implant-supported prosthesis for an edentulous arch--a technical note.

A technique for fabricating a provisional fixed prosthesis for an edentulous arch immediately following abutment connection, termed conversion prosthesis, is described in detail. Advantages of the restoration include the following: it provides a fixed prosthesis immediately following stage 2 surgery with improved function, stability, and distribution of load; it protects the sutured mucosa; it serves as a prototype for the final prosthesis; it can be used as a verification jig; it preserves the original vertical dimension of occlusion; it aids in obtaining and transferring the interocclusal record; it assists long-term patient maintenance; and it reduces treatment visits. The advantages of its use clearly outweigh the disadvantages.

Acrylic Resins↗

Influence of prosthesis material on the loading of implants that support a fixed partial prosthesis: in vivo study.

BACKGROUND: Since loading is increasingly believed to be a determining factor in the treatment outcome with oral implants, there is a need to expand the knowledge related to the biomechanics of oral implants and its influencing factors. PURPOSE: The aim of this study was to investigate the influence of prosthesis material on the distribution and magnitude of load on oral implants carrying a fixed partial prosthesis by in vivo quantification and qualification of this load. METHODS: Eight patients with in total nine three-unit fixed partial prostheses on three implants and three patients with in total four two-unit fixed partial prostheses on two implants were selected. Both metal and acrylic resin prostheses were made. Strain gauged abutments were used to measure the load on the supporting implants during controlled load application of 50 N on several positions along the occlusal surface of the prostheses and during maximal biting in maximal occlusion. Additional tests were conducted when the three-unit prostheses were supported only by two implants, thereby creating an extension pontic. RESULTS: A significantly better distribution of bending moments with the metal prostheses in comparison to the acrylic resin prostheses was observed in the case of the three-unit prostheses on two implants. No other difference in load or load distribution with the different prosthesis materials was noted. CONCLUSION: The clinical significance of the study reveals an increased risk for bending overload of the implants that are closest to the point of load application only in the case of acrylic resin long span prostheses or acrylic resin prostheses with extensions.

Acrylic Resins↗

Hearing results with clothespin ossiculoplasty: preliminary report on the Kraus Modified Schuring Ossicle-Cup Prosthesis (Clothespin Prosthesis).

The clothespin partial ossicular replacement prosthesis (PORP) is designed to increase joint stability during incus replacement ossiculoplasty. Fundamental modifications have been made in the Schuring ossicle-cup, which include a forked well, increased well wall thickness and length, and a flexible tip disk added to the shaft. The forked well functions like a straight clothespin rather than an inverted cup. The forked well enables the clothespin prothesis to slide down over the stapes superstructure, between the facial nerve canal and the promontory, to form a stable, mortise-and-tenon prosthesis-stapedial joint. Joint stability is enhanced because the inferior tine of the forked well is able to lever against the inferior surface of the stapes superstructure, creating a counterforce to gravity. This is in contrast to the more unstable ball-and-socket joint created by most partial ossicular replacement prostheses when they articulate with the stapes capitulum. The addition of a flexible disk to the shaft tip produces a tight, stable union between the prosthesis and the ossicular cap by increasing resistance at the shaft-ossicle interface. Fluoroplastic composition maximizes intraoperative versatility and reliability while the ossicle cap minimizes extrusions. One-year hearing results for twelve chronic ear patients with mobile stapes undergoing clothespin ossiculoplasty during intact canal wall tympanomastoidectomy revealed postoperative air-bone gaps within 20 dB in 92% of cases. The mean postoperative air-bone gap was 8.9 dB, and the mean improvement in air-bone gap was 14.4 dB.(ABSTRACT TRUNCATED AT 250 WORDS)

Adolescent↗

[Oral hygiene analysis, prosthesis hygiene and prosthesis stomatitis of old aged people--conclusions for gerostomatological care].

The oral health behaviour of old aged people, especially by pensioners in old people's homes or nursing homes is unsatisfactory, and is influenced from different social factors and social conditions. People with insufficient oral and prosthesis hygiene fall more frequent ill with prosthesis stomatitis compared to prosthesis wearers with clean artificial dentures. In addition the dental prosthesis care is not a part of daily personal hygiene in these investigated old people's homes. Patients and nurses are inadequate enlightened of oral hygiene measures.

Aged↗

Five-year followup of the Scott inflatable penile prosthesis and comparison with semirigid penile prosthesis.

The Scott inflatable penile prosthesis remains one of the most popular devices available for the surgical treatment of impotence despite high complication and reoperation rates. We present our 5-year followup of 116 inflatable prostheses placed before 1981 in 85 patients, with a 61 per cent overall 5-year complication rate. The incidence of complications by year after operation showed that most (22 per cent) devices failed within 1 year after implantation, with failure rates gradually decreasing to 6 and 7 per cent during years 4 and 5, respectively. Of 85 patients receiving an inflatable prosthesis 61 per cent underwent reoperation during the 5-year followup. A 5-year overall complication rate of only 14 per cent was seen in 29 Small-Carrion semirigid prostheses implanted during the same time. The results of numerous recent improvements in the design and structure of the Scott inflatable penile prosthesis to prevent mechanical device failure remain to be tested over the long term.

Adult↗

[Fully automated generation of hip prosthesis voxel models of the femur for finite element analysis. Comparison of direct and subsequent prosthesis implantation].

Two means of generating implant-bearing FE voxel models of the human femur are described and compared. The first method consists in the fully automatic production of a femur model from CT data and subsequent implantation of a prosthesis stem on the basis of a redefinition of existing voxel elements using geometrical data control. The second method processes the CT data of a femur already bearing a prosthesis. Here, the prosthesis elements are generated separately from the surrounding bony elements on the basis of the differing CT density thresholds. Although the two implantation algorithms produce comparable results, they have different fields of application. The method of numerical stress analysis involving automatic generation of voxel models can be applied to implant-bearing femurs. Clinical follow-up observations of patients with prostheses made of titanium can be supported by FE calculations.

Algorithms↗

A long-term follow-up study of unicompartmental replacement with a Marmor knee prosthesis and the introduction of a new ceramic prosthesis.

Unicompartmental replacement with a Marmor knee prosthesis was performed in 53 patients with unicompartmental osteoarthritis (OA). A five year or longer follow-up study of 15 joints in 13 of these patients was possible, three of which are now more than 10 years post-operative. All 13 patients reported absence of pain on weight-bearing and were able to flex the replaced knee more than 105 degrees. However, the postoperative femorotibial angle (FTA) appeared to be worsening with time, especially in those cases with an immediate postoperative FTA of more than 180 degrees. Since the needed size of the Marmor prosthesis is no longer available, we began using a ceramic prosthesis recently which we are introducing in this article.

Aged↗

[Treatment of femoral fractures on a total hip prosthesis using Charnley's "long stem" prosthesis. Apropos of 18 cases].

PURPOSE OF THE STUDY: This study was performed to analyse the clinical and radiological results obtained after the treatment of femoral fractures after total hip arthroplasties by a Charnley's extra long-stem prosthesis, and to compare these results with those obtained by alternative treatments proposed by various authors. MATERIALS: 18 patients, whose mean age was 68.5 years (extremes: 45 to 86 years). Cooke and Newman fractures classification showed a clear prominence of type III. In 8 cases we found a femoral loosening, prior to the fracture, divided as follows: 4 in grade III and 4 in grade IV, using Vives classification. Type I fractures were always associated to complete femoral loosening. METHOD: Clinical results were analysed by Merle d'Aubigné's scoring system, giving a pre-fracture global score of 13.5. Post-operative radiological analysis was made on the appearance of femoral radiolucent lines and/or modification of the femoral implant. RESULTS: 17 patients were followed, with a mean of 5 years (extremes: 1 to 14 years). Consolidation was always obtained. The global mean functional results were of 15.2, with score improvement, essentially, of soreness and stability. We found 12 good and very good results, 4 poor and 1 bad. Age (< 75 years) and fracture type (II and III) appeared to be important factors influencing the functional result, contrary to the lesional mechanism. 6 non-evolutive bone-cement radiolucent lines appeared, in immediate post-operative phase. One cement-prosthesis radiolucent line appeared later, leading to loosening and rupture of the implant. We deplore 3 stem twistings, of which only one led to implant rupture. Walking with support was possible at the 5th postoperative days. DISCUSSION: Our functional results are encouraging (12 good results, i.e. 71 per cent), compared with other treatments. This technique improved the global functional score. This is due to the simultaneous treatment of the fracture and of the eventual pre-traumatic associated femoral loosening. The technique allows a quick resumption of autonomy, a short hospitalization time for these elderly patients. The main disadvantage of the orthopaedic treatment is the prolonged decubitus and the important risk of secondary loosening. Osteosynthesis by plate has the advantage of keeping a maximum of osseous stock, but delays weight bearing, favours the non union by a large loss of periosteum. It never permits the treatment of the associated loosening during the same operation. It is also at the origin of a cement weakening, while fixing the proximal screws, leading to the difficulty of placing the prosthesis. Major disadvantage of proposed method is the use of a high quantity of cement to ensure stability of the implants; but this has never had negative consequences in our study. CONCLUSION: This surgical technique seems to be a satisfying alternative to the treatment of femoral fractures on total hip arthroplasty, due to the advantages obtained. It is reserved for elderly patients. However, these findings should be taken with caution, due to our small series.

Aged↗

[Total hip prosthesis for chronic juvenile arthritis. A review of a series of 34 prosthesis].

PURPOSE OF THE STUDY: The purpose of this study was to analyse the results of total hip arthroplasty for chronic juvenile arthritis in order to evaluate risks, problems and benefits of this procedure. MATERIAL AND METHODS: Between 1984 and 1992, 34 total hip prostheses were implanted for chronic juvenile arthritis in 20 patients. Most prosthesis were Zweymuller cementless prosthesis. Mean follow up was 5 years. RESULTS: Results were good. In 85 per cent of cases, patients had a normal activity recovery. Pain relief was very good since in 80 per cent cases patients had a total indolence. DISCUSSION: Beyond these good clinical results at this mean follow-up, the main interest of this study is to characterize two different periods in the surgical technique. The first period when cemented prosthesis was employed and the second one when cementless femoral implants with screwed acetabular component were used. Cementless prostheses appear to be a satisfying solution in this disease, preserving bones and showing very good radiological and functional results. CONCLUSION: Furthermore, the very low complication rate despite general discomfort may prompt us to use total hip arthroplasty for the treatment of chronic juvenile arthritis.

Adolescent↗

An annular prosthesis for the treatment of functional mitral regurgitation: finite element model analysis of a dog bone-shaped ring prosthesis.

BACKGROUND: Undersized annuloplasty is commonly used in the treatment of functional mitral regurgitation. However, in the case of severely dilated ventricles, annuloplasty may be inadequate to counteract leaflet tethering. My colleagues and I hypothesized that modifying the shape of the annular prosthesis to account for the specific anatomy of functional mitral regurgitation could challenge extreme leaflet tethering. METHODS: Using finite element model simulations, we tested valve competence after the implantation of conventional D-shaped versus dog bone-shaped annuloplasty rings, the latter of which was designed to selectively reduce the septolateral dimension of the annulus. Three models were compared: model A, simulating the native mitral valve; model B, simulating the same valve after annuloplasty with a conventional D-shaped annuloplasty; and model C, simulating a dog-bone annuloplasty ring implantation. Each model was then challenged by progressively pulling the tip of the papillary muscles away from the annulus plane to simulate ventricular remodeling and leaflet tethering. Valve competence was compared in each model for each degree of leaflet tethering. RESULTS: After maximal leaflet tethering simulation (4-mm apical displacement of the papillary tips), the regurgitant area increase was 70.4 mm2 for model A and 52.9 mm2 for model B. In model C, the regurgitant area was only negligibly affected by papillary displacement, increasing to 3.9 mm2. CONCLUSIONS: An annular prosthesis with selective reduction in the septolateral dimension is more effective than a conventional prosthesis for treating leaflet tethering in functional mitral regurgitation. Use of disease-specific annular prostheses is needed to improve the results of valve reconstruction.

Animals↗

[Use of a composite prosthesis (PL-PU99) versus a biological prosthesis (Surgisis) in an experimental model of temporary abdominal closure].

INTRODUCTION: In some diseases of peritoneal origin, temporary closure of the abdominal cavity is required to avoid compartmental syndrome. This allows normal intra-abdominal pressure to be maintained and the fascial edges to be preserved for subsequent definitive closure. MATERIAL AND METHOD: Defects (7 x 4 cm) were created in the anterior abdominal wall of New Zealand white rabbits and were repaired using an oval-shaped patch of a prosthesis designed by our team (PL-PU99) or a prosthesis of biological origin (Surgisis) of similar dimensions to the defects. The biomaterials were fixed to the cut edges of the wall by 2 polypropylene running sutures interrupted only at the corners, leaving the patch in contact with the atmosphere. Fourteen days after implantation, prosthesis/anchorage tissue specimens were taken for light and scanning electron microscopy, morphometric measurements and immunohistochemical macrophage identification (using the RAM-11 antibody). RESULTS: There were no cases of mortality or implant rejection. Small areas of loose adhesions were observed on some implants (covering 0.31 +/- 0.03% of the PL-PU99 implants and 31.60 +/- 7.35% of Surgisis). The neoperitoneum induced by both implant types was homogenous and well organized, with thicknesses of 427.60 +/- 8.38 microm (PL-PU99) and 171.99 +/- 18.70 microm (Surgisis). No significant differences were observed in terms of the macrophage reaction induced (PL-PU99 19.76 +/- 1.59%; Surgisis 21.07 +/- 8.93% macrophages). CONCLUSIONS: a) The PL-PU99 prosthesis provoked fewer adhesions and generated a thicker neoperitoneum. b) Both prostheses would probably be suitable for temporary closure of the abdominal cavity.

Abdominal Wall↗

[Tumour prosthesis in the treatment of metastases, loosening of prosthesis and fractures at the proximal femur (author's transl)].

19 patients were treated via a tumour prosthesis in the hip joint region. The indication resulted from osteolyses, loosening of prosthesis and subtrochanteric fractures in aged patients involving risk factors. The results show that application of a tumour prosthesis is a suitable method for bridging over major defects in the proximal femur to achieve early mobilisation of the patients associated with full load of the extremity on which the operation had been performed.

Adult↗

Effects of prosthesis materials and prosthesis splinting on peri-implant bone stress around implants in poor-quality bone: a numeric analysis.

PURPOSE: A 3-dimensional finite element model consisting of a bone block and 2 simulated premolar crowns supported by 2 adjacent cylindric implants without immediately surrounding cortical bone was generated and used to investigate the effects of prosthesis materials and prosthesis splinting on the peri-implant bone stress under static loads. MATERIALS AND METHODS: The peri-implant maximum equivalent bone stress (von Mises [VM] stress) was evaluated when a vertical or a horizontal load of 1 N was applied to the center of a single resin, gold alloy, or porcelain crown, nonsplinted or splinted to the adjacent crown. RESULTS: The numeric results indicated that: (1) in a single crown, no significant difference could be found in the maximum VM stress between different materials for both vertical and horizontal loading; (2) splinting the crowns reduced the maximum VM stress induced by the horizontal load, and the maximum VM stress increased about 14% for the horizontal loading when the restorative material was changed from gold alloy or porcelain to resin. DISCUSSION: Under the condition of this study's analysis, prosthesis materials of a single crown have insignificant effects on the peri-implant bone stress. Splinting the crowns reduced the peri-implant bone stress under horizontal load, and gold alloy and porcelain each demonstrated less peri-implant bone stress than resin in the splinted crown situation under static horizontal load. CONCLUSION: Splinting the crowns of adjacent implants with relatively stiff restorative materials is recommended for implants surrounded by poor-quality bone.

Alveolar Bone Loss↗

[Critical assessment of penile prosthesis implants: indication, choice of prosthesis, surgical technique and follow-up].

The surgical techniques for penile prosthesis implantation are well known and standardized. Multicomponent hydraulic prosthesis offer, without any doubt, the best guarantees in terms of function and aesthetic results. Nevertheless their insertion is sometime troublesome and a superficial knowledge of the technical problems may lead to complete and disappointing failures. In the present work the Authors report their personal experience with various types of penile prosthesis and describe in details, the different maneuvers which are needed for their correct implantation. Some variation of the original technique will be also described. The results obtained will also be described.

Adult↗

[Prosthesis endocarditis with embolization of a Smeloff-Cutter aortic valve prosthesis. Diagnosis, surgical management, clinical and hemodynamic course to 3 years' postoperative follow-up].

In a 47-year-old man a late postoperative chronic infective prosthetic valve endocarditis became evident 8 years after implantation of a Smeloff-Cutter aortic valve prosthesis. Signs and symptoms of valve endocarditis increased rapidly, so that within 12 months a total valve embolization was found intraoperatively. Three years after emergency reoperation and implantation of a Björk-Shiley prosthesis, good clinical and hemodynamic results were established. Thus, even in prosthesis valve endocarditis with severe consecutive hemodynamic impairment, immediate surgical treatment seems to be mandatory and can be performed successfully with good long-term results if the diagnosis is made in time and if effective antimicrobial therapy is begun.

Aortic Valve↗

Bone-preserving prosthesis with a single axis for treating osteonecrosis of the femoral head: midterm results for the thrust plate hip prosthesis.

We studied 27 patients (31 joints) who underwent total hip arthroplasty (THA) using the thrust plate hip prosthesis (TPP) for osteonecrosis of the femoral head. The mean follow-up period was 56 months (range 38-72 months). Clinical evaluation by the Merle d'Aubigne and Postel system showed a significant improvement from a preoperative mean score of 8.1 to a final mean follow-up score of 16.6. Mechanical loosening developed about 1 year postoperatively in one joint with a bone defect. Grade 1 stress shielding was observed in four joints. Although indications for the TPP are restricted to certain cases, unlike the conventional intramedullary stem, much can be expected of TPP. It is an outstanding prosthesis for osteonecrosis of the femoral head of young patients in terms of bone preservation and physiological load transfer.

Adult↗

[Prosthesis exchange with a cement-free ceramic prosthesis].

Representation of the causes of failure of cemented total hip prostheses concerning long-term-results due to wear problems and cement destruction. In order to avoid a further weakening of bony structures we recommend the use of the self-locking Autophor-prosthesis (Mittelmeier) in case of revision. At the same time additional bone-grafting for better ingrowth of the prosthesis often becomes necessary. By means of the casuistry of our clinic (1975-1983) with altogether 102 revision cases with self-locking Autophor-prostheses we represent the results. With the exception of 5 failure cases these results were very satisfactory.

Adult↗

Long-term follow-up in 185 patients after mitral valve replacement with the Lillehei-Kaster prosthesis. Overall results and prosthesis-related complications.

A follow-up was carried out in 185 patients after mitral valve replacement with the Lillehei-Kaster prosthesis. Fifty-eight males and one hundred and twenty-seven females provided a total of 876 years of observation. The operative mortality amounted to 13% for the total series and to 9.3% after elective surgery. The long-term survival for the total series was 67% after five years and 56% after 10 years. The great majority of survivors showed a marked improvement in functional capacity and a significant decrease in heart volume. In spite of long-term anticoagulant treatment thromboembolic events were the most frequent valve-related complications. Thrombosis of the valve occurred in eight patients and appeared to decrease with a change in the orientation of the valve. The percentage of patients free from thromboembolic events amounted to 76 +/- 5% after ten years. The percentage of patients free from valve-related morbidity and mortality was 66 +/- 5% after ten years. Valve related death accounted for 18% of all deaths and 26% of all late deaths. Fracture of the prosthesis was never encountered. These results compare favourably with those obtained with the Starr Edwards' or the Björk-Shiley prostheses.

Female↗