1,720,960 research outputs found
Maxillary sinus elevation with an alloplastic material and implants: 11 years of clinical and radiologic follow-up
No full textPurpose: The aim of this retrospective study was to determine the clinical and radiologic results, over an 11-year period, of resorbable hydroxyapatite used as a bone substitute in maxillary sinus elevation. Materials and Methods: Between 1996 and 2007, we treated 26 patients with maxillary sinus elevation (27 sinuses) using resorbable hydroxyapatite and simultaneous insertion of 47 titanium implants. Patients were recruited, screened, and accepted or rejected sequentially based on specific inclusion/exclusion criteria. Ten months later, 2-stage surgery and prosthetic rehabilitation were performed. Results: During the 11-year follow-up period (mean, 6 years), all the implants appeared clinically and radiologically integrated. The cumulative survival rate was 100%. During the observation period, the resorption of the graft apically to the implant was 1.8 mm on average. Conclusion: The posterior area of the maxilla often represents a challenging clinical situation because of either the lack of alveolar bone or the structural characteristics of the trabeculae in that specific area. The high survival rate of the implants and the stability of the mineralization of the graft confirmed that resorbable hydroxyapatite was a suitable material for sinus grafting
Bone resorption around dental implants placed in grafted sinuses: clinical and radiologic follow-up after up to 4 years
No full textPurpose: The long-term results of endosseous implants depend on the maintenance of bone support. The aim of this study was to evaluate radiologically bone resorption around dental implants placed in grafted sinuses after up to 4 years of function. Materials and Methods: Between 1997 and 2001, augmentation of the maxillary sinus floor with alloplastic (Biostite) or xenogenic (Bio-Oss) materials was performed in 34 patients. Results: Eighteen patients participated in the study. Twenty-six sinus augmentations were performed on these 18 patients, and they received 37 implants. The change in marginal bone level around the implants at the mesial side was 1 mm during the first year after the abutment connection, followed by an annual loss of 0.1 mm. The change in marginal bone level around the implants at the distal side was 1.1 mm during the first year after the abutment connection followed by an annual loss of 0.2 mm. Discussion: The implant survival rate observed in this study is in line with data previously reported for patients treated with implants in the posterior maxilla without bone atrophy. The results for implants placed into sinuses grafted with Bio-Oss were similar to the results for implants placed in sinuses grafted with Biostite. Conclusion: Although this study involved a limited number of procedures, it confirmed that alloplastic and xenogenic materials can be reliable for bone regeneration in subantral cavities. The angular defects present both at the distal and mesial sides of the implants were comparable to those observed at implants placed in native bone
A simplified method to assess precision of fit between framework and supporting implants. A preliminary study
No full textPurpose: To present a simplified method for assessment of precision of fit between screw-retained frameworks and supporting implants in clinical situations. Materials and Methods: Torque-angle signature analysis is a method for analysis of tension within a joint. The OsseoCare device developed by Nobel Biocare was utilized for the tests. Three titanium frameworks were fabricated on the same master cast according to 3 different methods: (1) 1-piece casting, (2) the CNC (computer numeric controlled) method, and (3) the CTiP (Cresco Ti Precision) method. These frameworks were used to test the device and indirectly the application of the torque-angle signature analysis technology. Results: The frameworks fabricated according to the CNC and CTiP methods demonstrated OsseoCare tracings similar to the reference models of passively fitting joints, while the 1-piece cast framework did not. Conclusion: According to this pilot study, the OsseoCare device and torque-angle signature analysis proved to be feasible for clinical assessment of fit between frameworks and supporting implants
Sinus elevation with alloplasts or xenogenic materials and implants : an up-to-4-year clinical and radiologic follow-up
No full textPURPOSE: The clinical and radiologic results of bone substitute application in the sinus elevation procedure were evaluated for up to 4 years after a grafting procedure followed by implant placement. MATERIALS AND METHODS: Between 1997 and 2001, augmentation of the maxillary sinus floor with alloplastic or xenogenic materials was performed in 34 nonsmoking patients with generally good health. However, only 18 patients attended all of the required annual clinical and radiographic examinations and thus were included in the study. Mean follow-up after implantation was 29 months. RESULTS: At the second-stage surgery all the implants were osseointegrated, except for 1 Frialit-2, which was removed. Following prosthetic rehabilitation no implant was lost after 4 years of function, for a prosthetic success rate of 100%. The cumulative implant survival rate after 48 months was 97% (36 of 37 implants). DISCUSSION: Osseointegrated implants are a reliable treatment option for restoring the posterior maxilla, and final predictability was not influenced by their placement in augmented areas after sinus elevation with bone substitutes. CONCLUSIONS: The survival rate obtained with this study is similar to that expected for implants placed in nongrafted areas. This study showed that alloplasts and xenogenic materials are reliable for bone regeneration in the subantral cavities, as they showed very low resorption in the present study
Soft tissue stability with immediate implants and concave abutments
No full textImplant therapy success in the anterior maxilla is judged not only by osseointegration, but also by having sound and stable peri-implant tissues that appear identical to the gingiva surrounding the healthy adjacent teeth. The creation of predictable peri-implant esthetics requires proper preservation of the osseous and soft tissues surrounding the failing teeth, proper three-dimensional implant placement, and proper understanding of prosthetic management. It is now possible to place immediate implants and immediate prostheses to improve esthetics and to simplify treatment, but this technique does not seem to have a stable long-term buccal mucosa. To avoid or reduce this negative effect it appears to be important to increase the thickness of the buccal tissues, and to use appropriate implant components. The aim of the present retrospective study was to observe the dimensional alterations of the peri-implant tissues after immediate implants and single-tooth restorations with concave abutments performed on 28 patients, with a mean followup time of 20.4 months
Retrospective clinical study of Osseotite implants : zero- to 5-year results
No full textPurpose: Over the last few years, particular attention has been paid to the implant surface and its influence on the formation and maintenance of surrounding bone. The surface of Osseotite implants (Implant Innovations) is produced by a process of thermal etching, which produces a surface with an average roughness that is twice that of machined implants produced by the same manufacturer. In addition to reducing osseointegration time, this factor appears to favor its maintenance over time. This study presents the results of a clinical trial of Osseotite implants. Materials and Methods: Five hundred fifty-five Osseotite implants were placed in 244 patients over 5 years, between September 1996 and September 2001. The average follow-up period from implant placement was 26 months (SD 13.1). Results: After the first surgical stage, 8 failures were noted in 6 patients. Life table analysis showed a cumulative survival rate of 98.5%, but no implant was lost after prosthetic loading, with a 100% survival rate both for the mandible and for the maxilla. For the prosthetic loading time, only the implants with more than 12 months of loading were considered, obtaining an average prosthetic loading time of 34 months (SD 9.2). Discussion: The implant survival rate after loading was 100% both in the anterior and posterior regions, and no difference was noted in relation to the different types of prostheses, or length and width of implants. Conclusion: The results obtained in this retrospective study population revealed an acceptable survival rate for these implant-supported restorations
Maxillary sinus floor augmentation with vegetal hydroxyapatite “versus” demineralized bovine bone : a randomized clinical study with a split-mouth design
Get PDFPurpose: The objective of this paper was to compare histologically and histomorphometrically a
hydroxyapatite originated by algae (Algipore) versus demineralized bovine bone (Bio-Oss Geistlich
Pharma, Wolhusen, Switzerland) utilised as bone substitutes in maxillary sinus floor elevation with
a split-mouth design.
Materials and Methods: Five healthy patients underwent a bilateral maxillary sinus floor elevation
procedure under local anesthesia. In each case, residual posterior maxillary bone height was between 2 mm and 5 mm. The original bone was augmented with a split-mouth design with 100% Algipore on the test side and 100% Bio-Oss on the contralateral control side. After a healing period of 6-8 months during the re-opening surgery biopsies were retrieved and Xive Implants (Dentsply Implants, Mannheim, Germany) were placed.
Results: At microscopic level both Bio-Oss and Algipore blocks resulted well osseointegrated,
without inflammatory infiltrate, with an high level of mineralization, without gap between the bone
and biomaterial interfaces that resulted indistinguishable. A close contact between the two faces was
observed without the presence of slits. Histomorphometrical analysis showed that, on average, the
percentage of medullary space was higher for the Bio-Oss compared with Algipore (38.61% ±8.90%
vs. 29.23% ±7.89%). In contrast, the mean value of residual particles of biomaterials was higher in
Algipore than in Bio-Oss specimens (42.86% ±18.61% vs. 22.30% ±6.40% respectively).
Conclusions: The data confirmed that sinus lift carried out with Algipore performed in a similar way
of that carried out with Bio-Oss and that this material is safe, predictable and without invasiveness
Going Beyond Counting First Authors in Author Co-citation Analysis
Get PDFThe present study examines one of the fundamental aspects of author co-citation analysis (ACA) - the way co-citation
counts are defined. Co-citation counting provides the data on which all subsequent statistical analyses and mappings
are based, and we compare ACA results based on two different types of co-citation counting - the traditional type that
only counts the first one among a cited work's authors on the one hand and a non-traditional type that takes into
account the first 5 authors of a cited work on the other hand. Results indicate that the picture produced through this non-traditional author co-citation counting contains more coherent author groups and is therefore considerably clearer. However, this picture represents fewer specialties in the research field being studied than that produced through the traditional first-author co-citation counting when the same number of top-ranked authors is selected and analyzed. Reasons for these effects are discussed
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