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Waldenburg, Switzerland

Schmoelz W.,Innsbruck Medical University | Mayr R.,Innsbruck Medical University | Schlottig F.,Thommen Medical | Ivanovic N.,Innsbruck Medical University | And 2 more authors.
Clinical Biomechanics

Background Screw anchorage in osteoporotic bone is still limited and makes treatment of osteoporotic fractures challenging for surgeons. Conventional screws fail in poor bone quality due to loosening at the screw-bone interface. A new technology should help to improve this interface. In a novel constant amelioration process technique, a polymer sleeve is melted by ultrasound in the predrilled screw hole prior to screw insertion. The purpose of this study was to investigate in vitro the effect of the constant amelioration process platform technology on primary screw anchorage. Methods Fresh frozen femoral heads (n = 6) and vertebrae (n = 6) were used to measure the maximum screw insertion torque of reference and constant amelioration process augmented screws. Specimens were cut in cranio-caudal direction, and the screws (reference and constant amelioration process) were implanted in predrilled holes in the trabecular structure on both sides of the cross section. This allowed the pairwise comparison of insertion torque for constant amelioration process and reference screws (femoral heads n = 18, vertebrae n = 12). Prior to screw insertion, a micro-CT scan was made to ensure comparable bone quality at the screw placement location. Findings The mean insertion torque for the constant amelioration process augmented screws in both, the femoral heads (44.2 Ncm, SD 14.7) and the vertebral bodies (13.5 Ncm, SD 6.3) was significantly higher than for the reference screws of the femoral heads (31.7 Ncm, SD 9.6, p < 0.001) and the vertebral bodies (7.1 Ncm, SD 4.5, p < 0.001). Interpretation The interconnection of the melted polymer sleeve with the surrounding trabecular bone in the constant amelioration process technique resulted in a higher screw insertion torque and can improve screw anchorage in osteoporotic trabecular bone. © 2016 Elsevier Ltd. All rights reserved. Source

Brinkmann J.,ETH Zurich | Brinkmann J.,MESA Institute for Nanotechnology | Hefti T.,ETH Zurich | Schlottig F.,Thommen Medical | And 2 more authors.

Osteoclasts are responsible for bone resorption and implant surface roughness promotes osseointegration. However, little is known about the effect of roughness on osteoclast activity. This study aims at the characterization of osteoclastic response to surface roughness. The number of osteoclasts, the tartrate-resistant acid phosphatase and matrix metalloproteinase (MMP) activities, the cell morphology and the actin-ring formation were examined on smooth (TS), acid-etched (TA) and sandblasted acid-etched (TLA) titanium and on native bone. Cell morphology was comparable on TA, TLA and bone, actin rings being similar in size on TLA and bone, but smaller on TA and virtually absent on TS. Gelatin zymography revealed increased proMMP-9 expression on TA, TLA, and bone compared to TS. In general, osteoclasts show similar characteristics on rough titanium surfaces and on bone, but reduced activity on smooth titanium surfaces. These results offer some insight into the involvement of osteoclasts in remodeling processes around implant surfaces. © The Author(s) 2012. Source

Stadlinger B.,TU Dresden | Ferguson S.J.,University of Bern | Eckelt U.,TU Dresden | Mai R.,TU Dresden | And 3 more authors.
British Journal of Oral and Maxillofacial Surgery

Two groups of titanium dental implants, identical in geometry but different in the treatment of their surfaces, were tested in an in vivo minipig model of the mandible. The surfaces that were tested were, first, sandblasted and acid-etched; and secondly, sandblasted, acid-etched, and conditioned. The removal torque was assessed at 2, 4, and 8 weeks after implantation (n = 6 animals in each healing period). The interfacial stiffness was also evaluated. All dental implants were well-integrated at the time of death. Removal torque values increased significantly over the course of 8 weeks. Removal torque and interfacial stiffness were increased for conditioned surfaces after 2 weeks, but there were no significant differences between the two surfaces. The sandblasted and acid-etched implants are the standard, and conditioning of the surface showed a tendency to increase early peri-implant formation of bone. © 2010 The British Association of Oral and Maxillofacial Surgeons. Source

Scharnweber D.,TU Dresden | Schlottig F.,Thommen Medical | Oswald S.,Leibniz Institute for Solid State and Materials Research | Becker K.,TU Dresden | Worch H.,TU Dresden
Journal of Materials Science: Materials in Medicine

The effect of two different etching procedures with inorganic acids (HSE and CSE)-one using additionally strongly oxidising conditions due to the presence of CrO3 (CSE)-and consecutive storage conditions (dry methanol and air) for previous corundum blasted titanium surfaces is compared with respect to their wettability behaviour and the potential of the etching processes for removing remaining blasting material. The etching procedures result in distinct different surface morphologies. Whereas the HSE surface shows sub-mm to sub-μm structures but neither porosity nor undercuts, the CSE surface is extremely rugged and porous with structures protruding the more homogeneously attacked areas by several micrometers. By EDX analysis both remaining blasting material and chromium and sulphur from the etching treatment has been detected on the CSE surfaces only. Both surfaces states show super-hydrophilic behaviour immediately after etching and storage up to 28 days in dry methanol. Whereas contact with air does not change super-hydrophilicity for the CSE samples, wettings angles of the HSE samples increase within minutes and reach about angles of about 60° and 90° after one and 2 days exposure to air, respectively. The increasing hydrophobicity is discussed with respect to the formation of a surface coverage from hydrocarbons originating from aromatic compounds present in traces in air. © 2009 Springer Science+Business Media, LLC. Source

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