Background: Short implants present superior failure rates for everybody.
Purpose: The aim of this theoretic study was to assess to what extent implant length and bicortical anchorage affect the way stress is transferred to implant components, the implant proper, and the surrounding bone.
Materials And Methods: Stress analysis was performed using finite element analysis. A three-dimensional linear elastic model was generated. All implants modeled were of the same diameter (3.75 mm) but varied in length, at 6, 7, 8, 9, 10, 11, and 12 mm (Brånemark System, Nobel Biocare AB, Gothenburg, Sweden). Each implant was modeled with a titanium abutment screw and abutment, a gold cylinder and prosthetic screw, and a ceramic crown. The implants were seated in a supporting bone structure consisting of cortical and cancellous bone. An occlusal load of 100 N was applied at a 30 degrees angle to the buccolingual plane.
Results: With the selected model and bone properties, the coronal cortical anchorage was dominating, and the bone stress concentrated to that area.
Conclusions: The maximum bone stress was virtually constant, independent of implant length and bicortical anchorage. The maximum implant stress, however, increased somewhat with implant length and bicortical anchorage.
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http://dx.doi.org/10.1111/j.1708-8208.2003.tb00208.x | DOI Listing |
J Speech Lang Hear Res
January 2025
Aix-Marseille Université, INSERM, INS, Institut de Neurosciences des Systèmes, France.
Purpose: Prelingual deaf children with cochlear implants show lower digit span test scores compared to normal-hearing peers, suggesting a working memory impairment. To pinpoint more precisely the subprocesses responsible for this impairment, we designed a sequence reproduction task with varying length (two to six stimuli), modality (auditory or visual), and compressibility (sequences with more or less regular patterns). Results on 22 school-age children with cochlear implants and 21 normal-hearing children revealed a deficit of children with cochlear implants only in the auditory modality.
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Cardiothoracic Department, Children's Health Ireland at Crumlin, Dublin, Ireland.
Lead strangulation is a dangerous complication of epicardial pacemaker insertion. This complication has been increasingly highlighted lately. Our institution has recently identified four cases over the past five years.
View Article and Find Full Text PDFNeurosurgery
January 2025
Division of Neurosurgery, Changi General Hospital, Singapore.
Background And Objective: The global average life expectancy has been increasing steadily as the quality of healthcare continues to improve. However, there is a paucity of data looking at surgical fixation of thoracolumbar spine fractures in patients ≥80 years (super-elderly). Aim of this study is to look at whether there is higher rate of complications from surgical fixation of thoracolumbar fractures in this group of patients.
View Article and Find Full Text PDFSpecimen-induced aberrations limit the penetration depth of standard optical imaging techniques in vivo, mainly due to the propagation of high NA beams in a non-homogenous medium. Overcoming these limitations requires complex optical imaging systems and techniques. Implantable high NA micro-optics can be a solution to tissue induced spherical aberrations, but in order to be implanted, they need to have reduced complexity, offering a lower surface to the host immune reaction.
View Article and Find Full Text PDFJ Dent Res
January 2025
Center for MicroElectroMechanical Systems, Universidade do Minho, Guimarães, Portugal.
In the present in vitro study, we evaluated the adhesion of an injectable platelet-rich fibrin (i-PRF) to laser-textured zirconia surfaces and their resultant friction behavior against bone tissue. Three types of zirconia surfaces were compared regarding the i-PRF coating effects: 1) grit blasted with 250-μm spherical alumina particles and acid etched with 20% hydrofluoric acid (ZLA), 2) laser textured with a random (RD) surface pattern, or 3) laser textured with a designed pattern based on 16 lines and 8 passages (L16N8). The coefficient of friction (COF) of the specimens was assessed on a reciprocating sliding pin-on-plate tribometer at 1-N normal load, 1 Hz, and a 2-mm stroke length.
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