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Hallmann L.,University of Zurich | Mehl A.,University of Zurich | Sereno N.,Invibio Biomaterial Solutions | Hammerle C.H.F.,University of Zurich
Applied Surface Science | Year: 2012

The purpose of this in vitro study was the evaluation of the bond strength of the adhesives/composite resin to Poly Ether Ether Ketone (PEEK) based dental polymer after using different surface conditioning methods. PEEK blanks were cut into discs. All disc specimens were polished with 800 grit SiC paper and divided into 6 main groups. Main groups were divided into 2 subgroups. The main groups of 32 specimens each were treated as follow: (1) control specimens (no treatment), (2) piranha solution etching, (3) abraded with 50 μm alumina particles and chemical etching, (4) abraded with 110 μm alumina particles and chemical etching, (5) abraded with 30 μm silica-coated alumina particles and chemical etching, (6) abraded with 110 μm silica-coated alumina particles and chemical etching. Plexiglas tubes filled with a composite resin (RelyX Unicem) were bonded to the specimens. The adhesives used were Heliobond and Clearfil Ceramic Primer. Each specimen was stored in distilled water (37 °C) for 3 days. Tensile bond strength was measured in a universal testing machine and failure methods were evaluated. Abraded surface with 50 μm alumina particles followed by etching with piranha solution lead to the highest bond strength of 21.4 MPa when Heliobond like adhesive was used. Tribochemical silica coated/etched PEEK surfaces did not have an effect on the bond strength. Non-treated PEEK surface was not able to establish a bond with composite resin. The proper choice of adhesive/composite resin system leads to a strong bond. Conclusion: Airborne particle abrasion in combination with piranha solution etching improves the adhesive properties of PEEK. © 2012 Elsevier B.V. Source

Poulsson A.H.C.,AO Research Institute Davos | Eglin D.,AO Research Institute Davos | Zeiter S.,AO Research Institute Davos | Camenisch K.,AO Research Institute Davos | And 5 more authors.
Biomaterials | Year: 2014

Machined and injection moulded polyetheretherketone (PEEK) implants with and without an oxygen plasma modification were prepared and implanted in sheep cancellous and cortical bone. After 4, 12 and 26 weeks, osseointegration was evaluated through mechanical push-out tests and histomorphometry. In the cancellous bone, push-out force increased with time, a trend toward higher force was observed for machined compared to moulded, and oxygen plasma modified compared to unmodified. On-going remodelling of the bone was detected in the periphery of the implants at 4 weeks. Minimal or no inflammation was observed with all the implants at all locations and time-points. Bone-implant contact (BIC) was quantified at all-time points and locations for all the four PEEK implant surfaces. The BIC values ranged from 15 to 75% with an average of 29±13% in the cancellous bone and 25-65% with an average of 50±12% in the cortical bone. In the cortical bone the BIC increased significantly from 4 to 26 weeks. This invivo study has identified that surface topography of PEEK implants influences osseointegration. In addition, oxygen plasma has the potential to increase bone-implant interface stability. This study provides a unique reference for further modifications and invivo assessment of PEEK implants. © 2014 Elsevier Ltd. Source

News Article
Site: http://www.materialstoday.com/news/

Victrex has announced that it will build a new PEEK composite facility for unidirectional (UD) tape and add new manufacturing capability for medical Trauma plate applications at its U.K. headquarters. Unidirectional (UD) tape is being used for Victrex’s partnership with Magma, an oil and gas ‘mega-program’ that focuses on m-pipe. Magma´s m-pipe is a high strength polymer carbon pipe which is reportedly 90% lighter than steel in water, is stronger than steel, and has a number of performance benefits, including being highly durable, corrosion resistant to seawater, CO2 and sour gas. Victrex’s UD tape composites are also being used in aerospace applications. In trauma, Victrex will continue to invest in specific downstream manufacturing facilities during 2016. Trauma plates composed of the high-performance composite, PEEK-OPTIMA Ultra Reinforced, will be delivered by Victrex´s medical division Invibio Biomaterial Solutions (Invibio). According to the company, the plates offer 50 times better fatigue resistance compared to metal, x-ray translucency to facilitate improved fracture repair bone alignment, and stress transfer characteristics that may accelerate the healing process and address the sizeable cases of poor fracture repair or device failures that can occur in metal-based solutions. The new facility is due to start construction in early 2016.

Hallab N.J.,Rush University Medical Center | Hallab N.J.,Bioengineering Solutions Inc. | McAllister K.,Rush University Medical Center | Brady M.,Invibio Biomaterial Solutions | Jarman-Smith M.,Invibio Biomaterial Solutions
Journal of Biomedical Materials Research - Part B Applied Biomaterials | Year: 2012

Biologic reactivity to orthopedic implant debris is generally the main determinant of long-term clinical performance where released polymeric particles of Ultra-high molecular weight polyethylene (UHMWPE) remain the most prevalent debris generated from metal-on-polymer bearing total joint arthroplasties. Polymeric alternatives to UHMWPE such as polyetherether-ketone (PEEK) may have increased wear resistance but the bioreactivity of PEEK-OPTIMA particles on peri-implant inflammation remains largely uncharacterized. We evaluated human monocyte/macrophage responses (THP-1s and primary human) when challenged by PEEK-OPTIMA, UHMWPE, and X-UHMWPE particles of three particle sizes (0.7 um, 2 um, and 10 um) at a dose of 20 particles-per-cell at 24- and 48-h time points. Macrophage responses were measured using cytotoxicity assays, viability assays, proliferation assays and cytokine analysis (IL-1b, IL-6, IL-8, MCP-1, and TNF-α). In general, there were no significant differences between PEEK-OPTIMA, UHMWPE, and X-UHMWPE particles on macrophage viability or proliferation. However, macrophages demonstrated greater cytotoxicity responses to UHMWPE and X-UHMWPE than to PEEK-OPTIMA at 24 and 48 h, where 0.7 μm-UHMWPE particles produced the highest amount of cytotoxicity. Particles of X-UHMWPE more than PEEK-OPTIMA and UHMWPE induced IL-1β, IL-6, MCP-1, and TNF-α at 24 h, p < 0.05 (no significant differences at 48 h). On average, cytokine production was more adversely affected by larger 10 μm particles than by 0.7 and 2 μm sized particles. While limitations of in vitro analysis apply to this study, PEEK-OPTIMA particles were more biocompatible than UHMWPE particles, in that they induced less inflammatory cytokine responses and thus, in part, demonstrates that PEEK-OPTIMA implant debris does not represent an increased inflammatory risk over that of UHMWPE. © 2011 Wiley Periodicals, Inc. Source

Berretta S.,University of Exeter | Ghita O.,University of Exeter | Evans K.E.,University of Exeter | Anderson A.,Invibio Biomaterial Solutions | Newman C.,Invibio Biomaterial Solutions
High Value Manufacturing: Advanced Research in Virtual and Rapid Prototyping - Proceedings of the 6th International Conference on Advanced Research and Rapid Prototyping, VR@P 2013 | Year: 2014

This paper investigates the effects of particles size and morphology on flowability of a range of polymeric powders (SLS and non-SLS grades). The effect of additives incorporation, as well as drying or sieving, on the flowability characteristics of the powders is also analyzed. The results show that the particle morphology has a stronger influence on the flowability than the particle size distribution. Moreover, the incorporation of additives has to be carefully considered in order to have positive effects on the powder flowability. © 2014 Taylor & Francis Group. Source

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