| 1. |
- Barkarmo, Sargon, et al.
(author)
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Nano-hydroxyapatite-coated PEEK implants : a pilot study in rabbit bone
- 2013
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In: Journal of Biomedical Materials Research. Part A. - : John Wiley & Sons. - 1549-3296 .- 1552-4965. ; 101A:2, s. 465-471
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Journal article (peer-reviewed)abstract
- Osseointegration of surface-modified polyetheretherketone (PEEK) implants was studied in vivo. A total of 18 cylinder-shaped PEEK implants were inserted in the femurs of nine New Zealand rabbits; half were coated with nanocrystalline hydroxyapatite (nanoHA) and half were uncoated controls. Healing time was 6 weeks. Samples were retrieved with the implant and surrounding tissue, processed to cut and ground sections, and analyzed histomorphometrically. The implant surfaces were analyzed with optical interferometry, scanning electron microscopy (SEM), atomic force microscopy, and X-ray photoelectron spectroscopy (XPS). NanoHA-coated PEEK surfaces had lower height deviation (Sa) than controls [mean ± SD: 0.41 μm (± 0.14) vs. 0.96 μm (± 0.28)]. SEM images showed the nanoHA crystals as a thin layer on the polymer surface. XPS analysis of the coated implants showed a Ca/P ratio of 1.67. Histomorphometry indicated that the nanoHA-coated implants had more bone-to-implant contact [16% (± 4.7) vs. 13% (± 9.3)] and more bone area [52% (± 9.5) vs. 45% (± 11.9)]. We found no difference between smooth nanoHA-coated cylinder-shaped PEEK implants and uncoated controls. However, higher mean bone-to-implant contact indicated better osseointegration in the coated implants than in the uncoated controls. The large number of lost implants was interpreted as a lack of primary stability due to implant design.
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| 3. |
- Dahlin, Christer, 1959, et al.
(author)
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Early biocompatibility of poly (ethylene glycol) hydrogel barrier materials for guided bone regeneration. An in vitro study using human gingival fibroblasts (HGF-1).
- 2014
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In: Clinical oral implants research. - : Wiley. - 1600-0501 .- 0905-7161. ; 25:1, s. 16-20
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Journal article (peer-reviewed)abstract
- OBJECTIVES: To evaluate the early cellular attachment and viability to modified polyethylene glycol (PEG) hydrogels with the influence of arginine-glycine-aspartic acid (RGD) in an in vitro model system. MATERIAL AND METHODS: Human gingival fibroblasts (HGF-1) were cultured on 6 different modalities of PEG hydrogel in hydrophobic polystyrene wells. A total of 7500cells/well (10000cells/cm(2) ) were dispersed over the PEG filled wells and incubated in triplicates for 24h, 7 and 13days. Cell numbers were calculated by means of a NucleoCounter. Cell viability was determined by measuring lactate dehydrogenase (LDH). For statistical analysis, nonparametric Kruska-Wallis test followed by Dunetts T3 test were used. RESULTS: All PEG modifications showed good biocompatibility, as demonstrated by low LDH values per cell at the earlier two time points. After 13days, all PEG modifications showed significantly lower number of cells compared with the controls, and the MX60 configurations demonstrated significantly higher LDH/cell values compared with the other hydrogels. CONCLUSIONS: Modifications of the physio-chemical properties of PEG hydrogels and the addition of RGD and spacers influenced the initial cellular response of cultured HGF-1 cells. With the exception of MX60 after 13days, all PEG formulations performed similarly well. Early cellular response should be considered when developing PEG-based material for clinical purposes.
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| 4. |
- Edblad, Thorsten, et al.
(author)
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Micro-topography of dental enamel and root cementum.
- 2009
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In: Swedish dental journal. - 0347-9994. ; 33:1, s. 41-8
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Journal article (peer-reviewed)abstract
- The focus for the present study was to characterise dental enamel and cementum at the cervical region of healthy teeth by use of interferometry. The effect of a protein-dissolving enzyme, used for cleaning (Neutrase) on the surface topography, was also evaluated. Knowledge about the normal variation of surface topography of natural teeth is limited. In the design of artificial surfaces, intended to replace the function of lost biological surfaces, detailed knowledge of the latter is therefore of great importance. Nine health caries free premolars were used. The root cementum of three teeth was used for evaluation of Neutrase on the surface. On the six remaining teeth, the differences between the surface textures of enamel and root cementum were evaluated using 3D Interferometry. No statistical significant effect of Neutrase was identified. A significant difference between enamel and root cementum concerning surface topography using the different 3D parameters was recorded. When comparing values from the literature, the topography of artificial materials used in dentistry show similarities with the topography of the enamel and root cementum surfaces evaluated.
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| 6. |
- Johansson, Martin L, et al.
(author)
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The microbiological profile of the bone-anchored hearing system.
- 2019
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In: 7th International Symposium on Bone Conduction Hearing and Related Technologies (OSSEO), At Miami beach, FL, USA.
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Conference paper (other academic/artistic)abstract
- Purpose The aim of this study was to evaluate methods for bacterial sampling and to acquire insight into the role of the microbiota on the clinical outcome of BAHS. Methods and Materials For the identification and quantification of colonising bacteria, 3 sampling techniques from 3 different compartments were evaluated: (i) retrieval of abutments, (ii) sampling of the peri-abutment exudate using paper-points and, (iii) sampling of the peri-abutment soft tissue using a biopsy punch. Results Quantification of viable bacteria was possible from all three compartments. At baseline the soft tissue was mainly colonised by anaerobic bacteria. Anaerobic bacteria and Staphylococcus spp. were subsequently detected in all three compartments at 3 and 12 months. During the one-year follow-up, the common skin coloniser Staphylococcus epidermidis was present at the implant site in most patients whereas Staphylococcus aureus was present in half of the patients. Several associations between clinical and microbiological parameters were found. Conclusion This study confirmed a suitable study design, sampling and analytical methodology to quantitate, describe and isolate the bacterial species associated to BAHS. Characterising the microbiota present at different sites surrounding BAHS as well as elucidating their associations with clinical parameters and host response markers may have relevance for the outcome following implantation.
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| 7. |
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| 8. |
- Svanborg, Lory Melin, et al.
(author)
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The effect of hydroxyapatite nanocrystals on early bone formation surrounding dental implants.
- 2011
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In: International journal of oral and maxillofacial surgery. - : Elsevier BV. - 1399-0020 .- 0901-5027. ; 40:3, s. 308-15
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Journal article (peer-reviewed)abstract
- The knowledge of how nanostructures might affect early bone healing and osseointegration is limited. The aim of this study was to investigate if nanometer thick coatings of hydroxyapatite nanocrystals applied on a moderately rough surface might enhance early bone healing on screw-shaped dental implants and to evaluate if the thickness of the coat influences healing. Sandblasted and acid etched titanium implants coated with two different thicknesses of hydroxyapatite (test implants) and sandblasted and acid etched titanium implants (control implants), were inserted in rabbit tibia. After a healing time of 2, 4 and 9 weeks, a removal torque analysis and a histological evaluation were performed. The results from the removal torque analysis showed a tendency for higher values for the double coated hydroxyapatite after 4 weeks and for both the coated surfaces after 9 weeks of healing. The histological evaluations indicated slightly more new bone formation with the coated implants compared with the control; the differences did not reach statistical significance. The present study could not support the importance of nanometer thick coatings of hydroxyapatite nanocrystals in early bone healing, at least not when applied on a blasted and etched surface and placed in a cortical bone.
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| 9. |
- Svensson Malchau, Karin, et al.
(author)
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Biofilm properties in relation to treatment outcome in patients with first-time periprosthetic hip or knee joint infection
- 2021
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In: Journal of Orthopaedic Translation. - : Elsevier BV. - 2214-031X. ; 30, s. 31-40
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Journal article (peer-reviewed)abstract
- Background: Periprosthetic joint infections (PJI) are challenging complications following arthroplasty. Staphylococci are a frequent cause of PJI and known biofilm producers. Biofilm formation decreases antimicrobial susceptibility, thereby challenging favourable treatment outcomes. The aims of this study were to characterize the biofilm abilities and antimicrobial susceptibilities of staphylococci causing first-time PJI and correlate them to clinical outcome (infection resolution and recurrence). Methods: Reoperations for PJI of the hip or knee between 1st January 2012 to 30th June 2015 performed at the Sahlgrenska University Hospital were identified in a local database. Medical records were reviewed and clinical parameters recorded for patients whose intraoperative bacterial isolates had been stored at the clinical laboratory. Staphylococcal strains isolated from reoperations due to first-time PJI were characterised by their ability to form biofilms using the microtiter plate test. Antimicrobial susceptibility of the strains was determined by minimum inhibitory concentration (MIC) when grown planktonically, and by minimum biofilm eradication concentration (MBEC) when grown as biofilms. MBEC determination was conducted using the Calgary biofilm device (CBD) and a custom-made antimicrobial susceptibility plate containing eight clinically relevant antimicrobial agents. Results: The study group included 49 patients (70 bacterial strains) from first-time PJI, whereof 24 (49%) patients had recurrent infection. Strong biofilm production was significantly associated with recurrent infection. Patients infected with strong biofilm producers had a five-fold increased risk for recurrent infection. Strains grown as biofilms were over 8000 times more resistant to antimicrobial agents compared to planktonic cultures. Biofilms were more susceptible to rifampicin compared to other antimicrobials in the assay. Increased biofilm susceptibility (MBEC > MIC) was observed for the majority of the bacterial strains and antimicrobial agents. Conclusions: Strong biofilm production was significantly associated with increased antimicrobial resistance and PJI recurrence. This underscores the importance of determining biofilm production and susceptibility as part of routine diagnostics in PJI. Strong staphylococcal biofilm production may have implications on therapeutic choices and suggest more extensive surgery. Furthermore, despite the increased biofilm resistance to rifampicin, results from this study support its use in staphylococcal PJI. The Translational Potential of this Article: Like for many biomaterial-associated infections, staphylococci are a common cause of PJI. Their ability to adhere to surfaces and produce biofilms on medical devices is proposed to play a role. However, clinical studies where biofilm properties are directly linked to patient outcome are scarce. This study demonstrates that the majority of staphylococci isolated from first-time PJI were biofilm producers with increased antimicrobial resistance. Patients suffering an infection caused by a staphylococcal strain with strong biofilm production ability had a five-fold greater risk of recurrent infection. This novel finding suggests the importance of evaluating biofilm production as a diagnostic procedure for the guidance of treatment decisions in PJI.
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| 10. |
- Svensson, Sara, 1981, et al.
(author)
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A novel soft tissue model for biomaterial-associated infection and inflammation - Bacteriological, morphological and molecular observations
- 2015
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In: Biomaterials. - : Elsevier BV. - 0142-9612 .- 1878-5905. ; 41, s. 106-121
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Journal article (peer-reviewed)abstract
- Infection constitutes a major risk for implant failure, but the reasons why biomaterial sites are more vulnerable than normal tissue are not fully elucidated. In this study, a soft tissue infection model was developed, allowing the analysis of cellular and molecular responses in each of the sub-compartments of the implant-tissue interface (on the implant surface, in the surrounding exudate and in the tissue). Smooth and nanostructured titanium disks with or without noble metal chemistry (silver, gold, palladium), and sham sites, were inoculated with Staphylococcus epidermidis and analysed with respect to number of viable bacteria, number, viability and gene expression of host cells, and using different morphological techniques after 4 h, 24 h and 72 h. Non-infected rats were controls. Results showed a transient inflammatory response at control sites, whereas bacterial administration resulted in higher recruitment of inflammatory cells (mainly polymorphonuclear), higher, continuous cell death and higher gene expression of tumour necrosis factor-alpha, interleukin-6, interleukin-8, Toll-like receptor 2 and elastase. At all time points, S. epidermidis was predominantly located in the interface zone, extra- and intracellularly, and lower levels were detected on the implants compared with surrounding exudate. This model allows detailed analysis of early events in inflammation and infection associated to biomaterials in vivo leading to insights into host defence mechanisms in biomaterial-associated infections.
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