| 1. |
- Alenezi, Ali, et al.
(author)
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Characteristics of 2 Different Commercially Available Implants with or without Nanotopography
- 2013
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In: International Journal of Dentistry. - : Hindawi Limited. - 1687-8736 .- 1687-8728. ; 2013:Art. no. 769768
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Journal article (peer-reviewed)abstract
- The aim of this study was to assess histologically and histomorphometrically the early bone forming properties after 3 weeks for 2 commercially available implants, one supposedly possessing nanotopography and one without, in a rabbit femur model. Twenty-four implants divided equally into 2 groups were utilized in this study. The first group (P-I MICRO+NANO) was a titanium oxide (TiO2) microblasted and noble gas ion bombarded surface while the second group (Ospol) was anodic oxidized surface with calcium and phosphate incorporation. The implants were placed in the rabbit femur unicortically and were allowed to heal for 3 weeks. After euthanasia, the samples were subjected to histologic sectioning and bone-implant contact and bone area were evaluated histomorphometrically under an optical microscope. The histomorphometric evaluation presented that the P-I MICRO+NANO implants demonstrated significantly higher new bone formation as compared to the Ospol implants. Within the limitations of this study, the results suggested that nanostructures presented significantly higher bone formation after 3 weeks in vivo, and the effect of chemistry was limited, which is indicative that nanotopography is effective at early healing periods.
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| 2. |
- Alenezi, Ali, et al.
(author)
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Osseointegration effects of local release of strontium ranelate from implant surfaces in rats
- 2019
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In: Journal of Materials Science: Materials in Medicine. - : Springer Science and Business Media LLC. - 0957-4530 .- 1573-4838. ; 30:10, s. 116-
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Journal article (peer-reviewed)abstract
- BACKGROUND : Numerous studies have reported the beneficial effects of strontium on bone growth, particularly by stimulating osteoblast proliferation and differentiation. Thus, strontium release around implants has been suggested as one possible strategy to enhance implant osseointegration. AIM : This study aimed to evaluate whether the local release of strontium ranelate (Sr-ranelate) from implants coated with mesoporous titania could improve bone formation around implants in an animal model. MATERIALS AND METHODS : Mesoporous titania (MT) thin coatings were formed utilizing the evaporation induced self-assembly (EISA) method using Pluronic (P123) with or without the addition of poly propylene glycol (PPG) to create materials with two different pore sizes. The MT was deposited on disks and mini-screws, both made of cp Ti grade IV. Scanning electron microscopy (SEM) was performed to characterize the MT using a Leo Ultra55 FEG instrument (Zeiss, Oberkochen, Germany). The MT was loaded with Sr-ranelate using soaking and the drug uptake and release kinetics to and from the surfaces were evaluated using quartz crystal microbalance with dissipation monitoring (QCM-D) utilizing a Q-sense E4 instrument. For the in vivo experiment, 24 adult rats were analyzed at two time points of implant healing (2 and 6 weeks). Titanium implants shaped as mini screws were coated with MT films and divided into two groups; supplied with Sr-ranelate (test group) and without Sr-ranelate (control group). Four implants (both test and control) were inserted in the tibia of each rat. The in vivo study was evaluated using histomorphometric analyses of the implant/bone interphase using optical microscopy. RESULTS : SEM images showed the successful formation of evenly distributed MT films covering the entire surface with pore sizes of 6 and 7.2 nm, respectively. The QCM-D analysis revealed an absorption of 3300 ng/cm2 of Sr-ranelate on the 7.2 nm MT, which was about 3 times more than the observed amount on the 6 nm MT (1200 ng/cm2). Both groups showed sustained release of Sr-ranelate from MT coated disks. The histomorphometric analysis revealed no significant differences in bone implant contact (BIC) and bone area (BA) between the implants with Sr-ranelate and implants in the control groups after 2 and 6 weeks of healing (BIC with a p-value of 0.43 after 2 weeks and 0.172 after 6 weeks; BA with a p-value of 0.503 after 2 weeks, and 0.088 after 6 weeks). The mean BIC and BA values within the same group showed significant increase among all groups between 2 and 6 weeks. CONCLUSION : This study could not confirm any positive effects of Sr-ranelate on implant osseointegration.
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| 3. |
- Barkarmo, Sargon, et al.
(author)
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Enhanced bone healing around nanohydroxyapatite-coated polyetheretherketone implants : An experimental study in rabbit bone
- 2014
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In: Journal of biomaterials applications. - : Sage Publications. - 0885-3282 .- 1530-8022. ; 29:5, s. 737-747
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Journal article (peer-reviewed)abstract
- Objective: To investigate the bone response to threaded polyetheretherketone (PEEK) implants coated with nanohydroxyapatite. Materials and methods: A total of 39 PEEK implants were coated with nanocrystalline hydroxyapatite and 39 uncoated implants were used as controls. The implant surface was characterized by optical interferometry and scanning electron microscope. The implants were inserted in the tibia and femur of 13 rabbits. After 6 weeks of healing, quantitative and qualitative analyses were performed. Results: The test implants showed significantly higher removal torque test values compared with the control group. Histomorphometric evaluation demonstrated higher bone-to-implant contact for the test implants; however, there were no differences in bone area between the groups. Qualitative histological analyses demonstrated inflammatory cellular reactions in close vicinity of both implant surfaces. A two-cell layer of foreign body giant cells was observed irrespective of sample type. Conclusion: Our findings demonstrate that implants with a threaded design render good stability to PEEK in both coated and uncoated implants. Nanohydroxyapatite-coated PEEK implants demonstrated improved bone formation compared with uncoated controls.
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| 4. |
- Bougas, Kostas, 1980, et al.
(author)
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In vitro Evaluation of Calcium Phosphate Precipitation on Possibly Bioactive Titanium Surfaces in the Presence of Laminin.
- 2011
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In: Journal of Oral & Maxillofacial Research. - : Stilus Optimus. - 2029-283X. ; 2:3, s. e3-
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Journal article (peer-reviewed)abstract
- Objectives: The aim of the present study was to evaluate calcium phosphate precipitation and the amount of precipitated protein on three potentially bioactive surfaces when adding laminin in simulated body fluid.Material and Methods: Blasted titanium discs were prepared by three different techniques claimed to provide bioactivity: alkali and heat treatment (AH), anodic oxidation (AO) or hydroxyapatite coating (HA). A blasted surface incubated in laminin-containing simulated body fuid served as a positive control (B) while a blasted surface incubated in non laminin-containing simulated body fuid served as a negative control (B-). The immersion time was 1 hour, 24 hours, 72 hours and 1 week. Surface topography was investigated by interferometry and morphology by Scanning Electron Microscopy (SEM). Analysis of the precipitated calcium and phosphorous was performed by Energy Dispersive X-ray Spectroscopy (EDX) and the adsorbed laminin was quantified by iodine (125I) labeling.Results: SEM demonstrated that all specimens except for the negative control were totally covered with calcium phosphate (CaP) after 1 week. EDX revealed that B- demonstrated lower sum of Ca and P levels compared to the other groups after 1 week. Iodine labeling demonstrated that laminin precipitated in a similar manner on the possibly bioactive surfaces as on the positive control surface.Conclusions: Our results indicate that laminin precipitates equally on all tested titanium surfaces and may function as a nucleation center thus locally elevating the calcium concentration. Nevertheless further studies are required to clarify the role of laminin in the interaction of biomaterials with the host bone tissue.
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| 5. |
- Bougas, Kostas, 1980, et al.
(author)
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Laminin Coating Promotes Calcium Phosphate Precipitation on Titanium Discs in vitro.
- 2011
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In: Journal of Oral & Maxillofacial Research. - : Stilus Optimus. - 2029-283X. ; 2:4, s. e5-
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Journal article (peer-reviewed)abstract
- Objectives: The objective of this study was to investigate the effect of a laminin coating on calcium phosphate precipitation on three potentially bioactive titanium surfaces in simulated body fluid.Material and Methods: Blasted titanium discs were prepared by alkali and heat treatment (AH), anodic oxidation (AO) or hydroxyapatite coating (HA) and subsequently coated with laminin. A laminin coated blasted surface (B) served as a positive control while a blasted non coated (B-) served as a negative control. Surface morphology was examined by Scanning Electron Microscopy (SEM). The analysis of the precipitated calcium and phosphorous was performed by Energy Dispersive X-ray Spectroscopy (EDX).Results: The thickness of the laminin coating was estimated at 26 Å by ellipsometry. Interferometry revealed that the coating process did not affect any of the tested topographical parameters on µm level when comparing B to B-. After 2 weeks of incubation in SBF, the alkali-heat treated discs displayed the highest calcium phosphate deposition and the B group showed higher levels of calcium phosphate than the B- group.Conclusions: Our results suggest that laminin may have the potential to be used as a coating agent in order to enhance the osseoinductive performance of biomaterial surfaces, with the protein molecules possibly functioning as nucleation centres for apatite formation. Nevertheless, in vivo studies are required in order to clarify the longevity of the coating and its performance in the complex biological environment.
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| 6. |
- Breding, Karin, 1983, et al.
(author)
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The Effect of Hydroxyapatite Nanocrystals on Osseointegration of Titanium Implants: An In Vivo Rabbit Study
- 2014
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In: International Journal of Dentistry. - : Hindawi Limited. - 1687-8736 .- 1687-8728. ; 2014, s. (article id) 171305-
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Journal article (peer-reviewed)abstract
- Osseointegration is dependent on implant surface characteristics, including surface chemistry and topography. The presence of nanosized calcium phosphates on the implant surface is interesting to investigate since they affect both the nanotopography and surface chemistry, forming a bone mineral resembling surface. In this work, the osseointegration of titanium implants with and without the presence of hydroxyapatite (HA) nanocrystals has been evaluated in vivo. The integration was examined using removal torque measurements and real-time polymerase chain reaction (RT-PCR) analysis. The study was performed using two healing time points, 3 and 12 weeks. The results showed that the torque needed to remove the implants was insignificant between the non- and HA-coated implants, both at weeks 3 and 12. The RT-PCR, however, showed significant differences for osteoblast, osteoclast, and proinflammation markers when HA nanocrystals were present.
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| 7. |
- Bryington, M. S., et al.
(author)
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The influence of nano hydroxyapatite coating on osseointegration after extended healing periods
- 2013
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In: Dental Materials. - : Elsevier BV. - 0109-5641 .- 1879-0097. ; 29:5, s. 514-520
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Journal article (peer-reviewed)abstract
- Objective. Studies observing early wound healing periods around dental implants demon-strate an implants ability to enhance osseointegration, the bone-implant interactions for extended healing periods though have not been thoroughly studied. Methods. Twenty threaded titanium alloy (Ti6Al4V, Grade 5) implants were inserted bilaterally, half prepared to impart stable hydroxyapatite nanoparticles onto a sand blasted and acid etched surface (HA) and half with a non-coated control surface with only heat treatment (HT), into eighteen rabbit femurs. At 12 weeks, the bone-implant blocks were retrieved for micro computed tomography (mu CT), histologic processing and histomorphometric evaluation. Results. The bone-to-implant contact for the entire threaded portion of the implant revealed 57.1% (21.0) for the HT group and 38.8% (17.7) for the HA group with a total bone area within the threads 72.5% (13.9) (HT) and 59.7% (12.5) (HA). The 3D reconstructed mu CT image corresponded to the histomorphometric results. Significance. It is suggested that multiple factors such as the change in topography and chemistry may have influenced the outcomes.
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| 8. |
- Cecchinato, Francesca, et al.
(author)
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In vitro evaluation of human fetal osteoblast response to magnesium loaded mesoporous TiO2 coating.
- 2014
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In: Journal of Biomedical Materials Research - Part A. - : Wiley. - 1552-4965 .- 1549-3296. ; 102:11, s. 3862-3871
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Journal article (peer-reviewed)abstract
- This work aimed to evaluate the in vitro response of Transfected Human Foetal Osteoblast (hFOB) cultured on a magnesium-loaded mesoporous TiO2 coating. The application of mesoporous films on titanium implant surfaces has shown very promising potential to enhance osseointegration. This type of coating has the ability to act as a framework to sustain bioactive agents and different drugs. Magnesium is the element that, after calcium, is the most frequently used to dope titanium implant surfaces, since it is crucial for protein formation, growth factor expression, and aids for bone mineral deposition on implant surfaces. Mesoporous TiO2 films with an average pore-size of 6 nm were produced by the evaporation-induced self-assembly method (EISA) and deposited onto titanium discs. Magnesium loading was performed by soaking the mesoporous TiO2 discs in a magnesium chloride solution. Surface characterization was conducted by SEM, XPS, optical interferometry, and AFM. Magnesium release profile was assessed at different time points using a Magnesium Detection kit. Cell morphology and spreading were observed with SEM. The cytoskeletal organization was stained with TRITC-conjugated Phalloidin and cell viability was evaluated through a mitochondrial colorimetric (MTT) assay. Furthermore, gene expression of bone markers and cell mineralization were analyzed by real time RT-PCR and alizarin-red staining, respectively. The surface chemical analysis by XPS revealed the successful adsorption of magnesium to the mesoporous coating. The AFM measurements revealed the presence of a nanostructured surface roughness. Osteoblasts viability and adhesion as well as the gene expression were unaffected by the addition of magnesium possibly due to its rapid burst release, however, were enhanced by the 3D nanostructure of the TiO2 layer.
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| 9. |
- Cecchinato, Francesca, et al.
(author)
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Modulation of the nanometer pore size improves magnesium adsorption into mesoporous titania coatings and promotes bone morphogenic protein 4 expression in adhering osteoblasts
- 2016
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In: Dental Materials. - : Elsevier. - 0109-5641 .- 1879-0097. ; 32:7, s. E148-E158
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Journal article (peer-reviewed)abstract
- Objective. Mesoporous (MP) titania films used as implant coatings have recently been considered as release systems for controlled administration of magnesium to enhance initial osteoblast proliferation in vitro. Tuning of the pore size in such titania films is aimed at increasing the osteogenic potential through effects on the total loading capacity and the release profile of magnesium. Methods. In this study, evaporation-induced self-assembly (EISA) was used with different structure-directing agents to form three mesoporous films with average pore sizes of 2 nm (MP1), 6 nm (MP2) and 7 nm (MP3). Mg adsorption and release was monitored using quartz crystal microbalance with dissipation (QCM-D). The film surfaces were characterized with atomic force microscopy (AFM), scanning electron microscopy (SEM) and X-ray photoelectron spectroscopy (XPS). The effect of different Mg release on osteogenesis was investigated in human fetal osteoblasts (hFOB) using pre-designed osteogenesis arrays and real-time polymerase chain reaction (RT-PCR Results. Results showed a sustained release from all the films investigated, with higher magnesium adsorption into MP1 and MP3 films. No significant differences were observed in the surface nanotopography of the films, either with or without the presence of magnesium. MP3 films (7 nm pore size) had the greatest effect on osteogenesis, up-regulating 15 bone-related genes after 1 week of hFOB growth and significantly promoting bone morphogenic protein (BMP4) expression after 3 weeks of growth Significance. The findings indicate that the increase in pore width on the nano scale significantly enhanced the bioactivity of the mesoporous coating, thus accelerating osteogenesis without creating differences in surface roughness. (C) 2016 The Academy of Dental Materials. Published by Elsevier Ltd. All rights reserved
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| 10. |
- Cecchinato, Francesca, et al.
(author)
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Osteogenic potential of human adipose-derived stromal cells on 3-dimensional mesoporous TiO2 coating with magnesium impregnation
- 2015
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In: Materials Science and Engineering C. - : Elsevier BV. - 0928-4931 .- 1873-0191. ; 52, s. 225-234
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Journal article (peer-reviewed)abstract
- The aim of this study was to evaluate the osteogenic response of human adipose-derived stromal cells (ADScs) to mesoporous titania (TiO2) coatings produced with evaporation-induced self-assembly method (EISA) and loaded with magnesium. Our emphasis with the magnesium release functionality was to modulate progenitor cell osteogenic differentiation under standard culture conditions. Osteogenic properties of the coatings were assessed for stromal cells by means of scanning electron microscopy (SEM) imaging, colorimetric mitochondrial viability assay (MTT), colorimetric alkaline phosphates activity (ALP) assay and real time RT-polymerase chain reaction (PCR). Using atomic force microscopy (AFM) it was shown that the surface expansion area (S-dr) was strongly enhanced by the presence of magnesium. From MTT results it was shown that ADSc viability was significantly increased on mesoporous surfaces compared to the non-porous one at a longer cell culture time. However, no differences were observed between the magnesium impregnated and non-impregnated surfaces. The alkaline phosphatase activity confirmed that ADSc started to differentiate into the osteogenic phenotype after 2 weeks of culturing. The gene expression profile at 2 weeks of cell growth showed that such coatings were capable to incorporate specific osteogenic markers inside their interconnected nano-pores and, at 3 weeks, ADSc differentiated into osteoblasts. Interestingly, magnesium significantly promoted the osteopontin gene expression, which is an essential gene for the early biomaterial-cell osteogenic interaction. (C) 2015 Elsevier B.V. All rights reserved.
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