| 1. |
- Cardemil, Carina, et al.
(författare)
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Strontium-doped calcium phosphate and hydroxyapatite granules promote different inflammatory and bone remodelling responses in normal and ovariectomised rats.
- 2013
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Ingår i: PLosOne. - : Public Library of Science (PLoS). - 1932-6203. ; 8:12
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Tidskriftsartikel (refereegranskat)abstract
- The healing of bone defects may be hindered by systemic conditions such as osteoporosis. Calcium phosphates, with or without ion substitutions, may provide advantages for bone augmentation. However, the mechanism of bone formation with these materials is unclear. The aim of this study was to evaluate the healing process in bone defects implanted with hydroxyapatite (HA) or strontium-doped calcium phosphate (SCP) granules, in non-ovariectomised (non-OVX) and ovariectomised (OVX) rats. After 0 (baseline), six and 28d, bone samples were harvested for gene expression analysis, histology and histomorphometry. Tumour necrosis factor-α (TNF-α), at six days, was higher in the HA, in non-OVX and OVX, whereas interleukin-6 (IL-6), at six and 28d, was higher in SCP, but only in non-OVX. Both materials produced a similar expression of the receptor activator of nuclear factor kappa-B ligand (RANKL). Higher expression of osteoclastic markers, calcitonin receptor (CR) and cathepsin K (CatK), were detected in the HA group, irrespective of non-OVX or OVX. The overall bone formation was comparable between HA and SCP, but with topological differences. The bone area was higher in the defect centre of the HA group, mainly in the OVX, and in the defect periphery of the SCP group, in both non-OVX and OVX. It is concluded that HA and SCP granules result in comparable bone formation in trabecular bone defects. As judged by gene expression and histological analyses, the two materials induced different inflammatory and bone remodelling responses. The modulatory effects are associated with differences in the spatial distribution of the newly formed bone.
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| 2. |
- Calon, Tim, et al.
(författare)
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Multimodal analysis of the tissue response to a bone-anchored hearing implant. : 11.Calon TGA, Johansson ML, Omar O, Shah FA, Budding D, Trobos M, Thomsen P, Stokroos RJ, Palmquist
- 2019
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Ingår i: 2nd Politzer Society Meeting/2nd World Congress of Otology, 28 May - 1 June, 2019, Warsaw, Poland..
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Konferensbidrag (övrigt vetenskapligt/konstnärligt)
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| 3. |
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| 4. |
- Johansson, Martin L, et al.
(författare)
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Non-invasive sampling procedure revealing the molecular events at different abutments of bone-anchored hearing systems–A prospective clinical pilot study
- 2022
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Ingår i: Frontiers in Neuroscience. - : Frontiers Media SA. - 1662-4548 .- 1662-453X. ; 16
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Tidskriftsartikel (refereegranskat)abstract
- Purpose: To investigate the molecular activities in different compartments around the bone-anchored hearing system (BAHS) with either electropolished or machined abutments and to correlate these activities with clinical and microbiological findings. Materials and methods: Twelve patients received machined or electropolished abutments after implant installation of BAHS. Peri-abutment fluid and tissue were collected from baseline to 12 months. Gene expression of cytokines and factors related to tissue healing and inflammation, regeneration and remodelling, as well as bacterial recognition were determined using quantitative-polymerase chain reaction (qPCR). The clinical status was evaluated using the Holgers scoring system, and bacterial colonisation was investigated by culturing. Results: The gene expression of inflammatory cytokines (IL-8, IL-1β, and IL-10) and bacteria-related Toll-like receptors (2 and 4) was higher in the peri-abutment fluid than at baseline and in the peri-abutment tissue at 3 and 12 months. Conversely, the expression of genes related to tissue regeneration (Coll1a1 and FOXO1) was higher in the tissue samples than in the peri-abutment fluid at 3 and 12 months. Electropolished abutments triggered higher expression of inflammatory cytokines (IL-8 and IL-1β) (in peri-abutment fluid) and regeneration factor FOXO1 (in peri-abutment tissue) than machined abutments. Several cytokine genes in the peri-abutment fluid correlated positively with the detection of aerobes, anaerobes and Staphylococcus species, as well as with high Holger scores. Conclusion: This study provides unprecedented molecular information on the biological processes of BAHS. Despite being apparently healed, the peri-abutment fluid harbours prolonged inflammatory activity in conjunction with the presence of different bacterial species. An electropolished abutment surface appears to be associated with stronger proinflammatory activity than that with a machined surface. The analysis of the peri-abutment fluid deserves further verification as a non-invasive sampling and diagnostic procedure of BAHS.
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| 5. |
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| 6. |
- Grandfield, Kathryn, et al.
(författare)
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Free form fabricated features on CoCr implants with and without hydroxyapatite coating in vivo : a comparative study of bone contact and bone growth induction
- 2011
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Ingår i: Journal of materials science. Materials in medicine. - : Springer Science and Business Media LLC. - 0957-4530 .- 1573-4838. ; 22:4, s. 899-906
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Tidskriftsartikel (refereegranskat)abstract
- The current study evaluates the in vivo response to free form fabricated cobalt chromium (CoCr) implants with and without hydroxyapatite (HA) plasma sprayed coatings. The free form fabrication method allowed for integration of complicated pyramidal surface structures on the cylindrical implant. Implants were press fit into the tibial metaphysis of nine New Zealand white rabbits. Animals were sacrificed and implants were removed and embedded. Histological analysis, histomorphometry and electron microscopy studies were performed. Focused ion beam was used to prepare thin sections for high-resolution transmission electron microscopy examination. The fabricated features allowed for effective bone in-growth and firm fixation after 6 weeks. Transmission electron microscopy investigations revealed intimate bone-implant integration at the nanometre scale for the HA coated samples. In addition, histomorphometry revealed a significantly higher bone contact on HA coated implants compared to native CoCr implants. It is concluded that free form fabrication in combination with HA coating improves the early fixation in bone under experimental conditions.
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| 7. |
- Johansson, Martin L, et al.
(författare)
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Multimodal Analysis of the Tissue Response to a Bone-Anchored Hearing Implant: Presentation of a Two-Year Case Report of a Patient With Recurrent Pain, Inflammation, and Infection, Including a Systematic Literature Review.
- 2021
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Ingår i: Frontiers in cellular and infection microbiology. - : Frontiers Media SA. - 2235-2988. ; 11
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Tidskriftsartikel (refereegranskat)abstract
- Osseointegration is a well-established concept used in applications including the percutaneous Bone-Anchored Hearing System (BAHS) and auricular rehabilitation. To date, few retrieved implants have been described. A systematic review including cases where percutaneous bone-anchored implants inserted in the temporal bone were retrieved and analyzed was performed. We also present the case of a patient who received a BAHS for mixed hearing loss. After the initial surgery, several episodes of soft tissue inflammation accompanied by pain were observed, leading to elective abutment removal 14 months post-surgery. Two years post-implantation, the implant was removed due to pain and subjected to a multiscale and multimodal analysis: microbial DNA using molecular fingerprinting, gene expression using quantitative real-time polymerase chain reaction (qPCR), X-ray microcomputed tomography (micro-CT), histology, histomorphometry, backscattered scanning electron microscopy (BSE-SEM), Raman spectroscopy, and fluorescence in situ hybridization (FISH). Evidence of osseointegration was provided via micro-CT, histology, BSE-SEM, and Raman spectroscopy. Polymicrobial colonization in the periabutment area and on the implant, including that with Staphylococcus aureus and Staphylococcus epidermidis, was determined using a molecular analysis via a 16S-23S rDNA interspace [IS]-region-based profiling method (IS-Pro). The histology suggested bacterial colonization in the skin and in the peri-implant bone. FISH confirmed the localization of S. aureus and coagulase-negative staphylococci in the skin. Ten articles (54 implants, 47 patients) met the inclusion criteria for the literature search. The analyzed samples were either BAHS (35 implants) or bone-anchored aural epitheses (19 implants) in situ between 2 weeks and 8years. Themainreasons for elective removal were nonuse/changes in treatment, pain, or skin reactions. Most samples were evaluated using histology, demonstrating osseointegration, but with the absence of bone under the implants' proximal flange. Taken together, the literature and this case report show clear evidence of osseointegration, despite prominent complications. Nevertheless, despite implant osseointegration, chronic pain related to the BAHS may be associated with a chronic bacterial infection and raised inflammatory response in the absence of macroscopic signs of infection. It is suggested that a multimodal analysis of peri-implant health provides possibilities for device improvements and to guide diagnostic and therapeutic strategies to alleviate the impact of complications.
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| 8. |
- Johansson, Martin L, et al.
(författare)
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Clinical retrieval and analysis of percutaneous bone-anchored hearing implants using multiple analytical methodologies
- 2020
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Ingår i: 11TH WORLD BIOMATERIALS CONGRESS 11 - 15 December 2020.
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Konferensbidrag (övrigt vetenskapligt/konstnärligt)abstract
- Introduction: The percutaneous bone-anchored hearing system (BAHS) is an established form of hearing treatment for conductive or mixed hearing loss and single sided deafness [1]. The system consists of a titanium implant inserted in the temporal bone and mounted with an abutment onto which a sound processor is attached. It is considered to be a successful treatment with generally good outcomes in terms of audiology and quality of life [2]. However, associated adverse outcomes, such as peri-abutment inflammation and infection, pain and numbness may necessitate intervention, device removal or implant loss [2, 3]. The clinician must rely on subjective clinical measurements, whereas information on the biological events at the tissue-BAHS interface remain inaccessible. Reports of analyses of planned, electively retrieved BAHS implants, performed under perfectly controlled circumstances, are rare [4, 5]. The aim with this study was to gain insight into the biological processes around percutaneous bone-conducting devices by analysing retrieved implants. Experimental methods: Through the establishment of a bilateral collaboration network with European clinics, a retrieval and analytical protocol have been implemented. This will allow correlation of the clinical data with the underpinning microbiological, molecular and morphological fingerprints at the tissue interface. Multiple analytical and correlative strategies have been used, enabling multiscale and multimodal investigation of the tissue interface. Different sampling procedures and analytical tools were employed, including X-ray micro-computed tomography (micro-CT), histology/histomorphometry, fluorescence in situ hybridization (FISH), microbiology, quantitative polymerase chain reaction (qPCR), backscattered electron scanning electron microscopy (BSE-SEM) and Raman spectroscopy. Results and discussions: So far, retrieval, preservation and investigation of six BAHS implants with surrounding tissue have been performed. Causes for removal (1-7 years after implantation) were chronic pain, recurrent inflammation, cancer and mechanical complications. After micro-CT analysis and the samples were embedded for histological and ultrastructural analyses. This presentation describes the sample preparation route allowing assessment of the different hierarchical levels of interest of the tissue interface. Examples of the results from the different analyses will be presented, with emphasis on correlating the clinical outcome with the analytical findings. Conclusions: The implementation of a retrieval protocol combined with a subsequent multi-scale analytical strategy enables a correlation between the clinical history of patients and the underpinning microbiological, molecular and morphological events in the tissues interfacing the electively removed or failed percutaneous bone-anchored hearing implants.
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| 9. |
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| 10. |
- Omar, Omar, et al.
(författare)
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In situ bone regeneration of large cranial defects using synthetic ceramic implants with a tailored composition and design
- 2020
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Ingår i: Proceedings of the National Academy of Sciences of the United States of America. - : Proceedings of the National Academy of Sciences. - 0027-8424 .- 1091-6490. ; 117:43, s. 26660-26671
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Tidskriftsartikel (refereegranskat)abstract
- The repair of large cranial defects with bone is a major clinical challenge that necessitates novel materials and engineering solutions. Three-dimensionally (3D) printed bioceramic (BioCer) implants consisting of additively manufactured titanium frames enveloped with CaP BioCer or titanium control implants with similar designs were implanted in the ovine skull and at s.c. sites and retrieved after 12 and 3 mo, respectively. Samples were collected for morphological, ultrastructural, and compositional analyses using histology, electron microscopy, and Raman spectroscopy. Here, we show that BioCer implants provide osteoinductive and microarchitectural cues that promote in situ bone regeneration at locations distant from existing host bone, whereas bone regeneration with inert titanium implants was confined to ingrowth from the defect boundaries. The BioCer implant promoted bone regeneration at nonosseous sites, and bone bonding to the implant was demonstrated at the ultrastructural level. BioCer transformed to carbonated apatite in vivo, and the regenerated bone displayed a molecular composition indistinguishable from that of native bone. Proof-of-principle that this approach may represent a shift from mere reconstruction to in situ regeneration was provided by a retrieved human specimen, showing that the BioCer was transformed into well-vascularized osteonal bone, with a morphology, ultrastructure, and composition similar to those of native human skull bone.
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