| 51. |
- Göransson, Anna, 1970, et al.
(författare)
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Inflammatory response to titanium surfaces with with Potential Bioactive Properties: An In Vitro Study
- 2006
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Ingår i: Clinical Implant Dentistry and Related Research. ; 8:4, s. 210-217
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Tidskriftsartikel (refereegranskat)abstract
- Background: The current hard tissue implants research aims to accelerate bone healing by designing surfaces that are bioactive. However, the role of the inflammatory response to these surfaces is so far incompletely described. Purpose: The aim of the study was to evaluate early inflammatory response in vitro to a potentially bioactive surface—an anodized surface with Mg ions incorporated (anodized/Mg)—and to compare it to a turned, a blasted, and an anodized surface. Materials and Methods: An interferometer was used for topographical characterizations. The disks were incubated with human mononuclear cells. Adherent cells were investigated with respect to number of cells, viability, differentiation, and cytokine production with and without lipopolysaccharide stimulation after 24 and 72 hours. Results: The number of adhered mononuclear cells differed significantly between the different modified surfaces, with the highest number on the anodized surface. However, there were no significant differences in cytokine production and differentiation between the different modified surfaces. The amount of anti-inflammatory mediator interleukin-10 remained over time, while the number of cells and pro-inflammatory cytokine tumor necrosis factor-α decreased. The cells were viable on all surfaces, respectively. Conclusion: The anodized surfaces with and without Mg ions showed an increased cell adherence, however, otherwise an inflammatory response similar to the turned and blasted surfaces. Furthermore, the potentially bioactive anodized/Mg surface showed a similar response to the TiUnite-like anodized surface despite the former having a surface roughness of a smoother character.
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| 52. |
- Halldin, Anders, et al.
(författare)
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Implant Stability and Bone Remodeling after 3 and 13 Days of Implantation with an Initial Static Strain
- 2014
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Ingår i: Clinical Implant Dentistry and Related Research. - : John Wiley & Sons. - 1523-0899 .- 1708-8208. ; 16:3, s. 383-393
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Tidskriftsartikel (refereegranskat)abstract
- Objective Bone is constantly exposed to dynamic and static loads, which induce both dynamic and static bone strains. Although numerous studies exist on the effect of dynamic strain on implant stability and bone remodeling, the effect of static strain needs further investigation. Therefore, the effect of two different static bone strain levels on implant stability and bone remodeling at two different implantation times was investigated in a rabbit model. Methods Two different test implants with a diametrical expansion of 0.15 mm (group A) and 0.05 mm (group B) creating initial static bone strains of 0.045 and 0.015, respectively. The implants were inserted in the proximal tibial metaphysis of 24 rabbits to observe the biological response at implant removal. Both groups were compared to control implants (group C), with no diametrical increase. The insertion torque (ITQ) was measured to represent the initial stability and the removal torque (RTQ) was measured to analyze the effect that static strain had on implant stability and bone remodeling after 3 and 13 days of implantation time. Results The ITQ and the RTQ values for test implants were significantly higher for both implantation times compared to control implants. A selection of histology samples was prepared to measure bone to implant contact (BIC). There was a tendency that the BIC values for test implants were higher compared to control implants. Conclusion These findings suggest that increased static bone strain creates higher implant stability at the time of insertion, and this increased stability is maintained throughout the observed period.
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| 53. |
- Halldin, Anders, et al.
(författare)
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The effect of static bone strain on implant stability of bone remodelling
- 2011
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Ingår i: Bone. - : Elsevier. - 8756-3282 .- 1873-2763. ; 49:4, s. 783-789
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Tidskriftsartikel (refereegranskat)abstract
- Bone remodeling is a process involving both dynamic and static bone strain. Although there exist numerous studies on the effect of dynamic strain on implant stability and bone remodeling, the effect of static strain has yet to be clarified. Hence, for this purpose, the effect of static bone strain on implant stability and bone remodeling was investigated in rabbits. Based on Finite Element (FE) simulation two different test implants, with a diametrical increase of 0.15 mm (group A) and 0.05 mm (group B) creating static strains in the bone of 0.045 and 0.015 respectively, were inserted in the femur (group A) and the proximal tibia metaphysis (groups A and B respectively) of 14 rabbits to observe the biological response. Both groups were compared to control implants, with no diametrical increase (group C), which were placed in the opposite leg. At the time of surgery, the insertion torque (ITQ) was measured to represent the initial stability. The rabbits were euthanized after 24 days and the removal torque (RTQ) was measured to analyze the effect on implant stability and bone remodeling. The mean ITQ value was significantly higher for both groups A and B compared to group C regardless of the bone type. The RTQ value was significantly higher in tibia for groups A and B compared to group C while group A placed in femur presented no significant difference compared to group C. The results suggest that increased static strain in the bone not only creates higher implant stability at the time of insertion, but also generates increased implant stability throughout the observation period.
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| 54. |
- Hjalmarsson, Lars, 1958, et al.
(författare)
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Cellular responses to cobalt-chrome and CP titanium - an in vitro comparison of frameworks for implant-retained oral prostheses : Cellreaktioner mot broskelett för implantatretinerade konstruktioner av kobolt-kromlegering och kommersiellt rent titan. En jämförande in vitro-studie.
- 2011
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Ingår i: Swedish Dental Journal. ; 35:4/11, s. 169-244
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Tidskriftsartikel (refereegranskat)abstract
- The responses of cell types in peri-implant tissues to cobalt-chrome and titanium were studied in vitro. Cylinders were made from both a cobalt-chrome alloy and commercially pure titanium (length 6 mm, diameter 7.9 mm). Plastic tubes were placed over the cylinders to create cell culture wells, in which human epithelial cells or mouse fibroblasts were cultivated. Cell viability was studied using the Alamar Blue™ method. The surface structure of two samples of each material was analyzed with optical interferometry. The morphology of cells grown on cylinders of each material was studied with scanning electronic microscopy. Epithelial cells and fibroblasts in the titanium group were more viable than those in the cobalt-chrome group (p = 0.001 and p = 0.000, respectively). The titanium surfaces had a greater height deviation (Sa, p = 0.027) but were less dense (Sds, p = 0.044) than the cobalt-chrome group. The scanning electronic microscopy revealed no major deviations from normal cell morphology. Within the limitations of the present study, the findings indicate that epithelial cells as well as fibroblasts have a stronger negative response to cobalt-chrome alloy than to titanium. We suggest that these differences can be explained only by the material per se and not by the minor differences in surface structure. Further and clinical studies are needed to confirm the significance of these findings.
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| 55. |
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| 56. |
- Jimbo, Ryo, 1979, et al.
(författare)
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Histological and three-dimensional evaluation of osseointegration to nanostructured calcium phosphate-coated implants.
- 2011
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Ingår i: Acta biomaterialia. - : Elsevier BV. - 1878-7568 .- 1742-7061.
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Tidskriftsartikel (refereegranskat)abstract
- Nanostructures on implant surfaces have been shown to enhance osseointegration; however, commonly used evaluation techniques are probably not sufficiently sensitive to fully determine the effects of this process. This study aimed to observe the osseointegration properties of nanostructured calcium phosphate (CaP)-coated implants, by using a combination of three-dimensional imaging and conventional histology. Titanium implants were coated with stable CaP nanoparticles using an immersion technique followed by heat treatment. Uncoated implants were used as the control. After topographical and chemical characterizations, implants were inserted into the rabbit femur. After 2 and 4weeks, the samples were retrieved for micro-computed tomography and histomorphometric evaluation. Scanning electron microscopy evaluation indicated that the implant surface was modified at the nanoscale by CaP to obtain surface textured with rod-shaped structures. Relative to the control, the bone-to-implant contact for the CaP-coated implant was significantly higher at 4weeks after the implant surgery. Further, corresponding 3-D images showed active bone formation surrounding the implant. 3-D quantification and 2-D histology demonstrated statistical correlation; moreover, 3-D quantification indicated a statistical decrease in bone density in the non-coated control implant group between 2 and 4weeks after the surgery. The application of 3-D evaluation further clarified the temporal characteristics and biological reaction of implants in bone.
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| 57. |
- Jimbo, Ryo, et al.
(författare)
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The biological response to three different nanostructures applied on smooth implant surfaces
- 2012
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Ingår i: Clinical Oral Implants Research. - Hoboken, USA : Wiley-Blackwell. - 0905-7161 .- 1600-0501. ; 23:6, s. 706-712
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Tidskriftsartikel (refereegranskat)abstract
- Objective: To evaluate the biological effects of three calcium phosphate (CaP) coatings with nanostructures on relatively smooth implant surfaces.Material and methods: Stable CaP nanoparticle suspensions of different particle sizes and structures were coated onto implants by immersion and subsequent heat treatment. An uncoated implant was used as the control. After topographical and chemical characterizations, implants were randomly inserted into rabbit tibiae for removal torque (RTQ) testing. To confirm the biological reaction, implants were placed in the bilateral femurs of three rabbits.Results: The topographical characterization showed that each surface had different nanostructural characteristics and X-ray photon spectroscopy showed various CaP compositions. The control and test groups had different nanotopographies; however, the differences among the test groups were only significant for Surfaces B and C and the rest were insignificant. The RTQ tests showed significantly higher values in two test groups (Surface A and Surface C). Histologically, no adverse effects were seen in any group. Histomorphometrical evaluation showed comparable or better osseointegration along the implant threads in the test groups.Conclusion: The three different CaP coatings with nanostructures on the implant surfaces had enhancing effects on osseointegration. Along with the surface nanotopography, the CaP chemistry might have influenced the biological outcomes.
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| 58. |
- 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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| 59. |
- Juodzbalys, Gintaras, et al.
(författare)
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Titanium dental implant surface micromorphology optimization.
- 2007
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Ingår i: The Journal of oral implantology. - 0160-6972. ; 33:4, s. 177-85
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Tidskriftsartikel (refereegranskat)abstract
- The purpose of this investigation was to create an acid-etched implant surface that is similar to that created by sandblasting combined with acid etching and to compare it with the surfaces of various commercially available screw-type implants. Titanium grade 5 disks were machined in preparation for acid etching. Tests were carried out using different acids and combinations of them with varying time exposures. All etched surfaces were scanned with an electron microscope, and digital images were created for visual evaluation and description of the surfaces. The etched surfaces were evaluated for surface morphology (combination of microroughness and waviness); the surface most like the sandblasted/acid-etched surface was best obtained with a combination of sulfuric and hydrochloric acids. The etched titanium disks were fixed in acrylic resin (2 were cut and polished and 2 were scored and fractured) and the surface profile was examined. In the second part of the investigation, 28 screw-shaped implants that were manufactured from commercially available titanium grade 5 were selected and divided into 2 groups: 3 implants were used as controls (machined surface), and 25 implants were processed using the preferred etching method determined in the first part of the investigation. Magnifications of 27, 200, and 2000 were used to analyze the first 2 consecutive crests of threads, flanks, and root of threads of each implant with the treated surface. A 3-dimensional optical interferometer was used to characterize the surface roughness of both control and test groups. Three screws were selected from each group and measured at 9 sites: 3 measurements each on the crest, root, and flank of the threads. To describe the surface roughness in numbers, the following parameters were used: the average height deviation (Sa), the developed interfacial area ratio (Sdr), the fastest decay autocorrelation length (Sal), and the density of summits (Sds). In addition, in a third experiment, the surfaces of 5 commercially available screw-type implants and the experimental ones were analyzed and compared. It was concluded that the new experimental acid-etched titanium surface had the features of a roughened titanium surface, with glossily microroughness and large waviness. In general, the experimental surface was significantly rougher than the selected commercially available implants and similar to a sandblasted/acid-etched surface (top Sa: 2.08 +/- 0.36 microm, Sdr: 1.34 +/- 0.3 microm, valleys: 1.16 +/- 0.1 microm and 0.68 +/- 0.1 microm, flanks: 2.24 +/- 0.8 microm and 1.27 +/- 0.1 microm, respectively).
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| 60. |
- Kanno, T., et al.
(författare)
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Topography, microhardness, and precision of fit on ready-made zirconia abutment before/after sintering process
- 2007
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Ingår i: Clin Implant Dent Relat Res. ; 9:3, s. 156-65
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Tidskriftsartikel (refereegranskat)abstract
- Background Sintering porcelain on a ceramic abutment may change the microstructure and result in aging processes that influence the mechanical properties, internal strain, and the three-dimensional form of the abutment, thus causing a possible misfit between the abutment and the fixture. Purpose The aim was to investigate topography, microhardness, and precision of fit on yttrium-stabilized zirconia (Y-TZP) abutments before/after the sintering process. Materials and Methods Ten Y-TZP abutment samples were ground to a shape used in the clinical situation and divided at random into two groups: before/after sintering. After the surface roughness was measured on all abutments, the abutments were connected to fixture replicas, embedded in resin, and cut in the longitudinal axis. Both sides of the cut samples were measured with respect to microhardness and minimum distance between fixture and abutment surface. t-Test, one-way analysis of variance, and Bonferroni multiple comparisons were used to investigate statistical significant differences. Results The surface roughness (S(a) and S(dr)) after sintering was significantly higher than before sintering. The total average values of microhardness after sintering were statistically lower than before sintering with a difference of 2%. The total distance between abutment/fixture before/after sintering demonstrated no statistically significant difference. Contact between abutment/fixture was most common at the top area of the fixture. Conclusion A slight decrease of microhardness and contamination of porcelain particles immediately below the veneered part were found on the Y-TZP abutment after sintering. The sintering process did not affect the precision of fit.
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