Prosthesis

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Leif Ivar Havelin - One of the best experts on this subject based on the ideXlab platform.

Ignace Naert - One of the best experts on this subject based on the ideXlab platform.

  • influence of Prosthesis material on the loading of implants that support a fixed partial Prosthesis in vivo study
    Clinical Implant Dentistry and Related Research, 2000
    Co-Authors: Joke Duyck, Hans Van Oostenvyck, Jos Vander Sloten, Michel De Cooman, Robert Puers, Ignace Naert
    Abstract:

    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.

  • A comparison of laser-welded titanium and conventional cast frameworks supported by implants in the partially edentulous jaw: a 3-year prospective multicenter study.
    International Journal of Prosthodontics, 2000
    Co-Authors: Torsten Jemt, P.j. Henry, B. Lindén, Ignace Naert, Hans-peter Weber, C Bergström
    Abstract:

    PURPOSE The purpose of this prospective multicenter study was to evaluate and compare the clinical performance of laser-welded titanium fixed partial implant-supported prostheses with conventional cast frameworks. MATERIALS AND METHODS Forty-two partially edentulous patients were provided with Branemark system implants and arranged into 2 groups. Group A was provided with a conventional cast framework with porcelain veneers in one side of the jaw and a laser-welded titanium framework with low-fusing porcelain on the other side. The patients in group B had an old implant Prosthesis replaced by a titanium framework Prosthesis. The patients were followed for 3 years after Prosthesis placement. Clinical and radiographic data were collected and analyzed. RESULTS Only one implant was lost, and all prostheses were still in function after 3 years. The 2 framework designs showed similar clinical performance with few clinical complications. Only one abutment screw (1%) and 9 porcelain tooth units (5%) fractured. Four prostheses experienced loose gold screws (6%). In group A, marginal bone loss was similar for both designs of prostheses, with a mean of 1.0 mm and 0.3 mm in the maxilla and mandible, respectively. No bone loss was observed on average in group B. No significant relationship (P > 0.05) was observed between marginal bone loss and placement of Prosthesis margin or Prosthesis design. CONCLUSION The use of laser-welded titanium frameworks seems to present similar clinical performance to conventional cast frameworks in partial implant situations after 3 years.

  • Influence of Prosthesis material on the loading of implants that support a fixed partial Prosthesis: in vivo study.
    Clinical implant dentistry and related research, 2000
    Co-Authors: Joke Duyck, Hans Van Oostenvyck, Jos Vander Sloten, Michel De Cooman, Robert Puers, Ignace Naert
    Abstract:

    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. 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. 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. 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. 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.

Sushil Allen Luis - One of the best experts on this subject based on the ideXlab platform.

  • usefulness of mitral valve prosthetic or bioprosthetic time velocity index ratio to detect prosthetic or bioprosthetic mitral valve dysfunction
    American Journal of Cardiology, 2017
    Co-Authors: Sushil Allen Luis, Lori A Blauwet, H Samardhi, C West, Ramila A Mehta, Chris R Luis, Gregory M Scalia, Fletcher A Miller, D Burstow
    Abstract:

    This study aimed to investigate the utility of transthoracic echocardiographic (TTE) Doppler-derived parameters in detection of mitral prosthetic dysfunction and to define optimal cut-off values for identification of such dysfunction by valve type. In total, 971 TTE studies (647 mechanical prostheses; 324 bioprostheses) were compared with transesophageal echocardiography for evaluation of mitral Prosthesis function. Among all prostheses, mitral valve Prosthesis (MVP) ratio (ratio of time velocity integral of MVP to that of left ventricular outflow tract; odds ratio [OR] 10.34, 95% confidence interval [95% CI] 6.43 to 16.61, p<0.001), E velocity (OR 3.23, 95% CI 1.61 to 6.47, p<0.001), and mean gradient (OR 1.13, 95% CI 1.02 to 1.25, p=0.02) provided good discrimination of clinically normal and clinically abnormal prostheses. Optimal cut-off values by receiver operating characteristic analysis for differentiating clinically normal and abnormal prostheses varied by Prosthesis type. Combining MVP ratio and E velocity improved specificity (92%) and positive predictive value (65%) compared with either parameter alone, with minimal decline in negative predictive value (92%). Pressure halftime (OR 0.99, 95% CI 0.98 to 1.00, p=0.04) did not differentiate between clinically normal and clinically abnormal prostheses but was useful in discriminating obstructed from normal and regurgitant prostheses. In conclusion, cut-off values for TTE-derived Doppler parameters of MVP function were specific to Prosthesis type and carried high sensitivity and specificity for identifying prosthetic valve dysfunction. MVP ratio was the best predictor of prosthetic dysfunction and, combined with E velocity, provided a useful parameter for determining likelihood of dysfunction and need for further assessment.

Jeanette Schulz-menger - One of the best experts on this subject based on the ideXlab platform.

  • Effects of heart valve prostheses on phase contrast flow measurements in Cardiovascular Magnetic Resonance – a phantom study
    Journal of Cardiovascular Magnetic Resonance, 2017
    Co-Authors: Johanna Richau, Matthias A. Dieringer, Julius Traber, Florian Von Knobelsdorff-brenkenhoff, Andreas Greiser, Carsten Schwenke, Jeanette Schulz-menger
    Abstract:

    Background Cardiovascular Magnetic Resonance is often used to evaluate patients after heart valve replacement. This study systematically analyses the influence of heart valve prostheses on phase contrast measurements in a phantom trial. Methods Two biological and one mechanical aortic valve prostheses were integrated in a flow phantom. B_0 maps and phase contrast measurements were acquired at a 1.5 T MR scanner using conventional gradient-echo sequences in predefined distances to the prostheses. Results were compared to measurements with a synthetic metal-free aortic valve. Results The flow results at the level of the Prosthesis differed significantly from the reference flow acquired before the level of the Prosthesis. The maximum flow miscalculation was 154 ml/s for one of the biological prostheses and 140 ml/s for the mechanical Prosthesis. Measurements with the synthetic aortic valve did not show significant deviations. Flow values measured approximately 20 mm distal to the level of the Prosthesis agreed with the reference flow for all tested all prostheses. Conclusions The tested heart valve prostheses lead to a significant deviation of the measured flow rates compared to a reference. A distance of 20 mm was effective in our setting to avoid this influence.

  • Effects of heart valve prostheses on phase contrast flow measurements in cardiovascular magnetic resonance - a phantom study
    Journal of cardiovascular magnetic resonance : official journal of the Society for Cardiovascular Magnetic Resonance, 2017
    Co-Authors: Johanna Richau, Matthias A. Dieringer, Julius Traber, Florian Von Knobelsdorff-brenkenhoff, Andreas Greiser, Carsten Schwenke, Jeanette Schulz-menger
    Abstract:

    Cardiovascular Magnetic Resonance is often used to evaluate patients after heart valve replacement. This study systematically analyses the influence of heart valve prostheses on phase contrast measurements in a phantom trial. Two biological and one mechanical aortic valve prostheses were integrated in a flow phantom. B0 maps and phase contrast measurements were acquired at a 1.5 T MR scanner using conventional gradient-echo sequences in predefined distances to the prostheses. Results were compared to measurements with a synthetic metal-free aortic valve. The flow results at the level of the Prosthesis differed significantly from the reference flow acquired before the level of the Prosthesis. The maximum flow miscalculation was 154 ml/s for one of the biological prostheses and 140 ml/s for the mechanical Prosthesis. Measurements with the synthetic aortic valve did not show significant deviations. Flow values measured approximately 20 mm distal to the level of the Prosthesis agreed with the reference flow for all tested all prostheses. The tested heart valve prostheses lead to a significant deviation of the measured flow rates compared to a reference. A distance of 20 mm was effective in our setting to avoid this influence.

Rene Verdonk - One of the best experts on this subject based on the ideXlab platform.

  • the oxford unicompartmental knee Prosthesis an independent 10 year survival analysis
    Knee Surgery Sports Traumatology Arthroscopy, 2006
    Co-Authors: P Vorlat, Filip Gheysen, Guy Putzeys, Dominique Cottenie, Tom Van Isacker, F Handelberg, Pierre Paul Casteleyn, Nicole Pouliart, Rene Verdonk
    Abstract:

    One hundred forty-nine medial prostheses were implanted in 140 patients between 1988 and 1996. After a mean of 67 months 28 patients had died, without the need for revision. Seventeen prostheses were lost to follow-up. Revision surgery using a total knee Prosthesis was performed in 16 cases. In four others, a lateral Prosthesis was implanted subsequently to a medial one. One of these four was revised to a total knee Prosthesis 6 years later. In another four cases, late complications of the meniscal bearing were treated with replacement of this bearing. The surviving prostheses were seen back after a mean of 126 months. The cumulative survival rate at 10 years was 82% for the whole population and 84% when knees with a previous high tibial osteotomy were excluded. Since these results compare poorly to the survival of total knee arthroplasty, this Prosthesis is not the first-choice implant. Because it preserves a maximum of bone stock and is revised to a total Prosthesis almost without difficulty, it is the first-choice implant for medial unicompartmental osteoarthritis in patients younger than 65. Further research is mandatory to confirm that this Prosthesis very rarely needs revision in patients older than 75. It should not be used in osteotomized knees.