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  • About
  • The Global ETD Search service is a free service for researchers to find electronic theses and dissertations. This service is provided by the Networked Digital Library of Theses and Dissertations.
    Our metadata is collected from universities around the world. If you manage a university/consortium/country archive and want to be added, details can be found on the NDLTD website.
1

Total wrist arthroplasty : A clinical, radiographic and biomechanical investigation

Sagerfors, Marcus January 2016 (has links)
Aim: To study patient-related functional outcome measures, implant survival and radiographic loosening after total wrist arthroplasty (TWA) using four different implants. To evaluate a new TWA design biomechanically and clinically. Methods: The studies included two cohort studies with prospectively collected data (n=206 and n=219), an anatomic and kinematic analysis in a cadaveric model and a pilot study (n=20). Results: The Maestro TWA had a significantly greater improvement of radial/ulnar deviation than the Biax and Remotion TWAs. Summarized patientrelated functional outcome was significantly better for the Maestro than for the Remotion TWA. Cumulative implant survival after 8 years was 94% for Remotion, and 95% for Maestro implants. Radiographic loosening five years postoperatively was present in 26% of the Biax wrists, 18% of those with Remotion, and 2% of those with Maestro. Following TWA with the new implant design in a cadaveric model, there were no statistically significant changes compared to a native wrist regarding flexion, extension, radial deviation, the extension/radial deviation component of the dart-thrower’s motion, or the circumduction range of motion. Clinically, there was significant improvement of COPM, PRWE and VAS pain scores. Wrist extension and ulnar deviation improved, while grip strength remained largely unchanged. Conclusions: TWA is a surgical procedure which may offer a high level of patient satisfaction. Implant design may affect patient-related functional outcome after TWA. Implant survival as well as the frequency of radiographic loosening differed considerably between the four types of implants and might be a result of different implant design. Kinematic analysis of the new TWA design suggests that a stable and functional wrist is achievable with this design. Surgical placement of the new total wrist implant was reproducible and the implant yielded good patient-related outcome measures in the short term. Since TWA is an evolving procedure, further studies are warranted in order to refine indications and the place for TWA in modern hand surgery.
2

On healing of titanium implants in iliac crest bone grafts

Sjöström, Mats January 2006 (has links)
Bone grafts and titanium implants are commonly used for surgical/prosthetic rehabilitation of the atrophic edentulous maxilla. The factors which influence bone graft healing and implant integration are not sufficiently understood. The aim of this dissertation was to evaluate autogenous bone grafting and delayed placement of titanium endosteal implants for reconstruction of the atrophic maxilla, including the effects of different patient factors on bone graft healing and integration of titanium implants into grafted bone. A total of 46 patients with severe maxillary atrophy received onlay- (n=35) or interpositional bone grafts (n=11) and 6 mo. later received 341 titanium endosteal implants. All bone grafts were harvested from the iliac crest. All patients received fixed dental bridges and were followed clinically and with radiographical examinations for 3 yr. In Papers I and II, a total of 68 titanium microimplants were placed and retrieved from the bone grafts at various time points for histological analysis of the bone graft-implant interface. Integration was better after 6 mo. healing than placement in conjunction with bone grafting. Implant integration was similar for the two bone-grafting techniques. In Papers III and IV, originally including 29 patients and 222 implants, implant stability was measured with resonance frequency analysis (RFA) at placement, abutment connection, after 6 mo. of loading (III) and after 3 yr. of loading (IV). Ten non-grafted patients measured at the same time points were used as controls (III). RFA showed equal implant stability in grafted bone vs. non-grafted bone (III). Stability did not change from the 6-mo. to the 3-yr. control. Cumulative survival was 90% after 3 yr. (21 implants failed). Thirteen implants were lost prior to loading and 8 during functional loading. The group of failed implants showed a lower primary RFA stability than those that remained stable for 3 yr. All patients received and maintained a fixed dental bridge throughout the study. In Paper V, the graft volume changes (GVC) during the 6-mo. healing period prior to implant placement were studied in 30 patients using computerized tomography. Blood samples were taken from 25 patients in conjunction with bone grafting and were analysed for 13 haematological factors. Bone mineral density (BMD) was measured in 21 patients. Biopsies of the bone grafts were analysed for bone volume fraction (BVF). GVC (loss) was correlated with decreased BMD of the lumbar vertebrae L2-L4. There was no correlation between the haematological factors and GVC. Implant failure was not correlated with BMD, BVF or GVC. This dissertation shows that surgical/prosthetic rehabilitation of the atrophic edentulous maxilla with autogenous iliac crest bone grafts and delayed placement of titanium implants after 6 mo. of graft healing is effective, reproducible and functional. RFA at placement may be able to predict later implant failure.
3

Healing of endosseous implants with different surface characteristics in grafted and non-grafted bone : clinical and experimental studies

Jungner, Måns January 2014 (has links)
Aims: This study uses radiological and clinical evaluations of the healing of endosseous titanium implants presented with different surface characteristics in the clinical situation (paper I-III) and experimentally to describe the early bone healing in maxillary sinus membrane elevation with and without the use of grafting material (paper IV). Material and methods: In paper I, 136 patients were treated with 394 dental implants – 199 were oxidized titanium implants (Nobel Biocare TiUnite) and 195 were turned titanium surface implants (Nobel Biocare Mark III). Implant survival rates were retrospectively investigated after a minimum of five months after functional loading of the implants. At the five-year follow-up (paper II), eight patients were deceased and 128 were invited. Twenty-five patients refrained from participating in the study. The remaining 103 patients (287 implants – 133 with a turned surface and 154 with an oxidized surface) were examined after at least five years of functional loading. Clinical examinations of bleeding on probing (BoP) and pocket depth (PD) were performed. Intraoral radiographs were used to assess marginal bone levels (MBLs). In paper III, 28 patients were subjected to autologous bone graft and delayed implant placement, with a total of 92 dental implants. Thirteen patients received 47 implants with a turned surface and 15 patients received 45 implants with an oxidized surface. After a minimum of five years of functional loading, all patients were clinically examined regarding PD and BoP. The MBL was measured in intraoral radiographs. Cone beam computed tomography (CBCT) was used to evaluate the apical bone level (ABL) of the implants and intra-sinus conditions. The experimental study (paper IV) used nine adult male tufted capuchin primates (Cebus apella). Eight animals were subjected to bilateral maxillary sinus membrane elevation using a lateral replaceable bone window technique. One oxidized dental implant was placed in the residual bone of the sinus floor, protruding into the maxillary sinus cavity on both sides. In four animals, one sinus was left without any additional treatment, while the contralateral sinus was filled with autologous bone grafts from the tibia. In two animals, the implants were inserted under the elevated sinus membrane on both sides. In two animals, the sinus membrane was totally removed bilaterally before placement of implants. The animals were euthanized after 10 (n=4) or 45 (n=4) days. One non-operated animal representing pristine tissue conditions served as the control. The maxillary sinuses with implants were retrieved and further processed to prepare light microscopic ground sections or decalcified sections for immunohistochemical analyses. Results: In paper I seven implants were lost in five patients – six in the maxilla and one in the mandible. All failed implants were Mark III turned implants. The overall implant survival rate was 98.2% with a survival rate of 96.4% for implants with turned surface after a minimum of five months after functional loading. In paper II, one additional oxidized implant failed, giving an overall cumulative survival rate of 94.7 and 99.4%, respectively, after at least five years of functional loading. There was no difference for BoP, PD, or MBL between turned and oxidized implants. A total of two implants, three oxidized and one turned, showed a PD > 3 mm, MBL > 4 mm, and BoP. However, none of these were associated with suppurative infection on examination. In paper III no difference was found between the two implants surfaces used in terms of PD, BoP, MBL, or ABL. Pathological reactions to the sinus membrane were seen in four of the patients (14%). Radiographic signs of sinus pathology were not correlated to either survival rate of the implants or any of the investigated parameters. In the experimental paper IV, bone formation started from the bottom of the sinus floor, sprouting into the granulation tissue along the implant surface under the elevated membrane irrespective of time and surgical technique. Bone formation was not seen in direct conjunction with the sinus membrane. A distinct expression of osteopontin was observed in the serous glands of deeper portion of the lamina propria in direct connection with the elevated sinus membrane and close to the implant within all groups. Conclusion: After more than five years of function in non-grafted patients, oxidized implants had a survival rate higher than turned implants, although this was not statistically significant. No difference was found in MBL, PD, or BoP. Grafting of the maxillary sinus floor with intra- orally harvested bone and delayed placement of either turned or oxidized implants resulted in equally high long-term survival rates, MBL, ABL, and BoP. Pathological findings in the maxillary sinus cavity, in terms of sinus membrane health, are few and not correlated to any of the other investigated parameters. In the experimental study bone formation after sinus membrane elevation with or without additional bone grafts started at the sinus floor and sprouted into the elevated space along the implant surface. Removal of the membrane resulted in less bone formation. The sinus membrane did not seem to present osteoinductive potential in sinus membrane elevation procedures.
4

Oberlidimplantate bei Patienten mit Fazialisparese - eine vergleichende Untersuchung von starren und flexiblen Implantaten

Kuhnt, Christoph Paul 28 August 2019 (has links)
In der vorgelegten Dissertation werden verschiedene Oberlidimplantate bei Patienten mit Fazialisparese hinsichtlich ihrer postoperativen Komplikationen verglichen. Hierzu wurde eine retrospektive Kohortenstudie am Krankengut der Klinik für Mund-, Kiefer- und plastischen Gesichtschirurgie initiiert.:1. Einleitung 1 2. Therapie des Lagophthalmus mit Metallimplantaten 3 2.1 Entwicklung von Lidimplantaten 3 2.2 Workflow zur Lidimplantation 6 2.2.1 Indikation, Alternativen, Implantatauswahl 6 2.2.2 Operationsmethode 8 2.3 Fragestellung/Rationale der Studie 10 3. Publikation 12 4. Zusammenfassung 20 5. Anlagen 23 5.1 Abbildungsverzeichnis 23 5.2 Darstellung des eigenen Beitrags 24 5.3 Selbstständigkeitserklärung 25 5.4 Curriculum vitae 26 5.5 Publikationen des Autors 27 6. Danksagung 28
5

Bewertung des Langzeiterfolgs der kaufunktionellen Rehabilitation mit implantatgetragenem Zahnersatz in Kombination mit autogenem Knochentransfer anhand unterschiedlicher statistischer Verfahren / Long-term results of masticatory rehabilitation in patients treated with dental implants and bone grafts using different statistical methods

Stock, Vera 06 October 2010 (has links)
No description available.

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