| 1. |
- Barkarmo, Sargon, et al.
(författare)
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Biofilm formation on polyetheretherketone and titanium surfaces
- 2019
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Ingår i: Clinical and Experimental Dental Research. - : Wiley. - 2057-4347. ; 5:4, s. 427-437
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Tidskriftsartikel (refereegranskat)abstract
- Objective: Polyetheretherketone (PEEK) is a polymer used in devices in orthopedic and dental rehabilitation. The aim of this in vitro study was to compare biofilm formation by a range of important oral bacterial species on PEEK, blasted PEEK, commercially pure titanium (cp-Ti), and titanium-6 aluminium-4 vanadium (Ti6Al4V). Material and methods: Coin-shaped samples were manufactured, and the surfaces were characterized using optical interferometry, scanning electron microscopy, energy-dispersive X-ray spectroscopy, and contact angle measurements. Bacterial species of Streptococcus sanguinis, Streptococcus oralis, Enterococcus faecalis, and Streptococcus gordonii were cultured on the four material surfaces for varying amounts of time. Biofilms were quantified following staining with crystal violet. Results: Roughness and contact angle results showed blasted PEEK>PEEK>cp-Ti=Ti6Al4V. There was increased biofilm formation on blasted PEEK by S. sanguinis, S. oralis, and S. gordonii, whereas the bacterial adhesion was similar on PEEK, cp-Ti, and Ti6Al4V. The bacterial growth of E. faecalis was significantly higher on cp-Ti compared with the other three groups. Conclusion: The results, taking into consideration the biofilm formation, suggest that PEEK should perform as well as cp-Ti or TiAl6V4 when used as a dental restorative material. © 2019 The Authors. Clinical and Experimental Dental Research published by John Wiley & Sons Ltd.
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| 2. |
- Barkarmo, Sargon
(författare)
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In vivo and in vitro studies of polyetheretherketone: bone formation, inflammatory response and biofilm formation
- 2019
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Doktorsavhandling (övrigt vetenskapligt/konstnärligt)abstract
- In prosthetic dentistry, restorative materials are used to replace missing teeth and tissues, so as to maintain oral functionalities and comfort for the patient. Depending on the clinical problem, metals, ceramics or polymers, are used both in dentistry and orthopedics. The present thesis focuses on the polymer material polyetheretherketone (PEEK), which has been used in orthopedic applications for about 30 years, mainly as a component of spinal devices - as such it has provided good clinical outcomes. PEEK has recently been adopted as part of dental rehabilitation owing to its many favorable properties, including high-level mechanical strength, chemical resistance, and biocompatibility. Therefore, it is of interest and important to extend our basic understanding of PEEK as a material that can be used in various prosthetic devices. Moreover, it is important to investigate whether modifications made to the surface of the material generate outcomes that may be translated to prosthetic dentistry, thereby using PEEK as a more broadly applicable dental material. The overall aim of this thesis was to use in vivo and in vitro experimental methods to investigate the potential of PEEK as a material for use in dental devices. In vivo studies were conducted to investigate the host bone responses to cylindrically shaped and threaded PEEK implants that were coated with nanocrystalline hydroxyapatite (nanoHA), as compared to uncoated control implants. The results revealed significantly higher mean values for the biomechanical and histomorphometric parameters for the nanoHA PEEK, as compared to the control material. The levels of cytokines expressed by peripheral blood mononuclear cells (PBMCs) when exposed in vitro to PEEK, blasted PEEK, and titanium 6-aluminum 4-vanadium (Ti6Al4V) were investigated at different time-points. The PBMCs produced significantly higher levels of pro-inflammatory cytokines when exposed to the PEEK surface than when exposed to the Ti6Al4V surface. The blasted PEEK surface induced the highest level of proinflammatory cytokine release from the PBMCs. The ability to form a biofilm in vitro was assessed by inoculating oral bacterial species onto PEEK, blasted PEEK, commercially pure titanium (cp-Ti), and Ti6Al4V. Biofilm formation was quantified after staining with crystal violet. The blasted PEEK showed increased biofilm formation by S. sanguinis, S. oralis and S. gordonii as compared to the other surfaces, while the levels of bacterial adhesion to PEEK, cp-Ti, and Ti6Al4V were similar. It appears that nanoHa-coated, threaded PEEK implants improve bone formation, as compared to uncoated PEEK implants, and that PEEK induces a stronger inflammatory response than does Ti6Al4V. The biofilm formation results suggest that the level of bacterial adhesion to PEEK is similar to that of cp-Ti and Ti6AlV4. Within the limitations of the methods used in the present thesis, it can be concluded that PEEK may have potential as a material for use in various dental applications.
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| 3. |
- Barkarmo, Sargon, et al.
(författare)
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Inflammatory cytokine release from human peripheral blood mononuclear cells exposed to polyetheretherketone and titanium-6 aluminum-4 vanadium in vitro.
- 2018
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Ingår i: Journal of biomaterials applications. - : SAGE Publications. - 1530-8022 .- 0885-3282. ; 33:2, s. 245-258
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Tidskriftsartikel (refereegranskat)abstract
- Objective To investigate the cytokine expression profiles of blood cells exposed to polyetheretherketone and titanium-6 aluminum-4 vanadium materials in vitro. Materials and methods Coin-shaped samples composed of titanium-6 aluminum-4 vanadium, polyetheretherketone, and blasted polyetheretherketone were manufactured. The surfaces of the coins were characterized using optical interferometry, scanning electron microscopy, and contact angle measurements. Peripheral blood mononuclear cells collected from 10 blood donors were cultured for one, three, and six days in the presence or absence of the coins, and then assayed for cytokine production. Quantification of the peripheral blood mononuclear cells attached to the coins was performed using confocal microscopy after immunofluorescence staining. Results The machined titanium-6 aluminum-4 vanadium coins had a smoother surface topography compared to the machined polyetheretherketone and blasted polyetheretherketone. The highest mean contact angle was noted for the blasted polyetheretherketone, followed by the machined polyetheretherketone and titanium-6 aluminum-4 vanadium. The peripheral blood mononuclear cells produced significantly more proinflammatory cytokines when exposed to the polyetheretherketone surface compared to the titanium-6 aluminum-4 vanadium surface, while the blasted polyetheretherketone induced the highest level of proinflammatory cytokine release from the peripheral blood mononuclear cells. Significantly more cells attached to both polyetheretherketone surfaces, as compared to the titanium-6 aluminum-4 vanadium surface. Conclusion Polyetheretherketone induces a stronger inflammatory response from peripheral blood mononuclear cells than does titanium-6 aluminum-4 vanadium. Surface topography has an impact on cytokine release from peripheral blood mononuclear cells.
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| 4. |
- Johansson, Pär, et al.
(författare)
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Biomechanical, histological, and computed X-ray tomographic analyses of hydroxyapatite coated PEEK implants in an extended healing model in rabbit
- 2018
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Ingår i: Journal of Biomedical Materials Research Part A. - : Wiley. - 1549-3296 .- 1552-4965. ; 106:5, s. 1440-1447
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Tidskriftsartikel (refereegranskat)abstract
- A nanosized hydroxyapatite (HA) modification on polyetheretherketone (PEEK) using a novel spin coating technique was investigated in a rabbit model. Spin coating technique creates a 20-40 nm thick layer of nanosized HA particles with similar shape, size, and crystallinity as human bone. Some implants were designed with a perforating hole in the apical region to mimic a fusion chamber of a spinal implant. The coating nano-structures were assessed using a scanning electron microscope. The in vivo response to HA-PEEK was compared to untreated PEEK with respect to removal torque, histomorphometry, and computed microtomography. The HA-coated and pure PEEK implants were inserted in the tibia and femur bone according to simple randomization. The rabbits were sacrificed 20 weeks after implantation. Removal torque analysis showed significantly higher values for HA-PEEK. Qualitative histological evaluation revealed an intimate contact between PEEK and the bone at the threads and perforated hole. Histomorphometric assessment showed higher bone-implant and bone area values for HA-PEEK but without statistical significance. The effect of the HA coating showed most prominent effect in the removal torque which may be correlated to an alteration in the bone quality around the HA-PEEK implants. (c) 2018 Wiley Periodicals, Inc. J Biomed Mater Res Part A: 106A: 1440-1447, 2018.
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