| 1. |
- Franke Stenport, Victoria, 1970, et al.
(författare)
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Precipitation of calcium phosphate in the presence of albumin on titanium implants with four different possibly bioactive surface preparations. An in vitro study
- 2008
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Ingår i: Journal of Materials Science: Materials in Medicine. - : Springer Science and Business Media LLC. - 0957-4530 .- 1573-4838. ; 19:12, s. 3497-3505
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Tidskriftsartikel (refereegranskat)abstract
- The aim of the present study was to compare the nucleating behaviour on four types of bioactive surfaces by using the simulated body fluid (SBF) model with the presence albumin. Titanium discs were blasted (B) and then prepared by alkali and heat treatment (AH), anodic oxidation (AO), fluoridation (F), or hydroxyapatite coating (HA). The discs were immersed in SBF with 4.5 mg/ml albumin for 3 days, 1, 2, 3 and 4 weeks and analysed with scanning electron microscopy/energy dispersive X-ray analysis (SEM/EDX) and X-ray photoelectron spectroscopy (XPS). Topographic surface characterisation was performed with a contact stylus profilometer. The results demonstrated that the bioactive surfaces initiated an enhanced calcium phosphate (CaP) formation and a more rapid increase of protein content was present on the bioactive surfaces compared to the blasted control surface. The observation was present on all bioactive surfaces. The fact that there was a difference between the bioactive surfaces and the blasted control surface with respect to precipitation of CaP and protein content on the surfaces support the fact that there may be biochemical advantages in vivo by using a bioactive surface.
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| 2. |
- Göransson, Anna, 1970, et al.
(författare)
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An in vitro comparison of possibly bioactive titanium implant surfaces.
- 2009
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Ingår i: Journal of Biomedical Materials Research Part A. - : Wiley. - 1552-4965 .- 1549-3296. ; 88:4, s. 1037-1047
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Tidskriftsartikel (refereegranskat)abstract
- The aim of the study was to compare Ca and P formation (CaP) and subsequent bone cell response of a blasted and four different possibly bioactive commercially pure (cp) titanium surfaces; 1. Fluoride etched (Fluoride), 2. Alkali-heat treated (AH), 3. Magnesium ion incorporated anodized (TiMgO), and 4. Nano HA coated and heat treated (nano HA) in vitro. Furthermore, to evaluate the significance of the SBF formed CaP coat on bone cell response. The surfaces were characterized by Optical Interferometry, Scanning Electron Microscopy (SEM) and X-ray Photoelectron Spectroscopy (XPS). CaP formation was evaluated after 12, 24 and 72 h in simulated body fluid (SBF). Primary human mandibular osteoblast-like cells were cultured on the various surfaces subjected to SBF for 72 h. Cellular attachment, differentiation (osteocalcin) and protein production (TGF-beta(1)) was evaluated after 3 h and 10 days respectively. Despite different morphological appearances, the roughness of the differently modified surfaces was similar. The possibly bioactive surfaces gave rise to an earlier CaP formation than the blasted surface, however, after 72 h the blasted surface demonstrated increased CaP formation compared to the possibly bioactive surfaces. Subsequent bone cell attachment was correlated to neither surface roughness nor the amount of formed CaP after SBF treatment. In contrast, osteocalcin and TGF-beta(1) production were largely correlated to the amount of CaP formed on the surfaces. However, bone response (cell attachment, osteocalcin and TGF-F production) on the blasted controls were similar or increased compared to the SBF treated fluoridated, AH and TiMgO surface. (c) 2008 Wiley Periodicals, Inc. J Biomed Mater Res, 2008.
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| 3. |
- 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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| 4. |
- Meirelles, Luiz, 1974, et al.
(författare)
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Bone reaction to nano hydroxyapatite modified titanium implants placed in a gap-healing model
- 2008
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Ingår i: Journal Biomedical MAterials Research - A. - : Wiley. - 1549-3296 .- 1552-4965. ; 87:3, s. 624-631
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Tidskriftsartikel (refereegranskat)abstract
- Nanohydroxyapatite materials show similar chemistry to the bone apatite and depending on the underlying topography and the method of preparation, the nanohydroxyapatite may simulate the specific arrangement of the crystals in bone. Hydroxyapatite (HA) and other CaP materials have been indicated in cases in which the optimal surgical fit is not achievable during surgery, and the HA surface properties may enhance bone filling of the defect area. In this study, very smooth electropolished titanium implants were used as substrata for nano-HA surface modification and as control. One of each implant (control and nano HA) was placed in the rabbit tibia in a surgical site 0.7 mm wider than the implant diameter, resulting in a gap of 0.35 mm on each implant side. Implant stability was ensured by a fixating plate fastened with two side screws. Topographical evaluation performed with an optical interferometer revealed the absence of microstructures on both implants and higher resolution evaluation with AFM showed similar nanoroughness parameters. Surface pores detected on the AFM measurements had similar diameter, depth, and surface porosity (%). Histological evaluation demonstrated similar bone formation for the nano HA and electropolished implants after 4 weeks of healing. These results do not support that nano-HA chemistry and nanotopography will enhance bone formation when placed in a gap-healing model. The very smooth surface may have prevented optimal activity of the material and future studies may evaluate the synergic effects of the surface chemistry, micro, and nanotopography, establishing the optimal parameters for each of them.
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| 5. |
- Meirelles, Luiz, 1974, et al.
(författare)
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Effect of hydroxyapatite and titania nanostructures on early in vivo bone response
- 2008
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Ingår i: Clinical Implant Dentistry and Related Research. - : Wiley. - 1708-8208 .- 1523-0899. ; 10:4, s. 245-254
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Tidskriftsartikel (refereegranskat)abstract
- Objective: Hydroxyapatite or titania nano structures were applied on smooth titanium implant cylinders. The aim was to investigate whether nano HA may result in enhanced osseointegration compared to nano titania structures. Material and Methods: Surface topography evaluation included detailed characterization of nano size structures present at the implant surface combined with surface roughness parameters at the micro- and nano- meter level of resolution. Microstructures were removed from the surface to ensure that bone response observed was dependent only on the nanotopography and/or chemistry of the surface. Early in vivo bone response (4 weeks) evaluation was investigated in a rabbit model. Results: In the present study, nano titania coated implants showed an increased coverage area and feature density, forming a homogenous layer compared to nano HA implants. Bone response observed at 4 weeks could not be explained by the surface chemistry. New formed bone connected to the original cortical bone demonstrated an increase of 24% for the nano titania compared to the nano HA implant, although the difference was not statistically significant. Conclusion: Thus, no evidence of enhanced bone formation to nano hydroxyapatite modified implants was observed compared to nano titania modified implants. The presence of specific nano structures; dependent on the surface modification exhibiting different size and distribution did modulate in vivo bone response.
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| 6. |
- Meirelles, Luiz, 1974, et al.
(författare)
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The effect of chemical and nano topographical modifications on early stage of osseointegration
- 2008
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Ingår i: The International Journal of Oral & Maxillofacial Implants. - 0882-2786. ; 23:4, s. 641-7
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Tidskriftsartikel (refereegranskat)abstract
- Purpose: To investigate the effect of chemically modified implants with similar micro but different nano topography on early stage of osseointegration. Materials and Methods: Screw shaped implants were placed in the flat proximal medial tibial methaphyses of 10 New Zealand white rabbits. Blasted (control); blasted-fluoride and blasted-nano HA implants were investigated. Surface evaluation included chemical analyses with x-ray photoelectron spectroscopy, morphological analyses with scanning electron microscopy and topographical analyses with interferometry. Bone response was investigated with removal torque measurements and histological analyses after a healing period of 4 weeks. Results: Chemical analyses revealed the presence of Ti, O, C and N in all implant groups. The blasted-F group revealed F and the blasted nano HA group Ca and P with simultaneous decrease of Ti and O. Surface roughness parameters showed a slight decrease of the average height deviation for the blasted nano-HA and blasted-F compared to the blasted control implants. SEM images at high magnification indicated the presence of nano structures on the chemically modified implants. Removal torque (RTQ) mean values revealed an increase of 17% to 25% for the chemically modified implants compared to the control implants and the histological analyses demonstrated a similar enhanced bone formation to the chemically modified implants with nanostructures. Conclusion: Chemical modifications used in the present study were capable of producing a unique nano topography and together with the ions present at the implant surface may explain the increased RTQ and histomorphometric values after a healing period of 4 weeks.
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| 7. |
- Svanborg, Lory Melin, et al.
(författare)
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Evaluation of bone healing on sandblasted and Acid etched implants coated with nanocrystalline hydroxyapatite: an in vivo study in rabbit femur
- 2014
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Ingår i: International Journal of Dentistry. - : Hindawi Limited. - 1687-8728 .- 1687-8736. ; 2014
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Tidskriftsartikel (refereegranskat)abstract
- This study aimed at investigating if a coating of hydroxyapatite nanocrystals would enhance bone healing over time in trabecular bone. Sandblasted and acid etched titanium implants with and without a submicron thick coat of hydroxyapatite nanocrystals (nano-HA) were implanted in rabbit femur with healing times of 2, 4, and 9 weeks. Removal torque analyses and histological evaluations were performed. The torque analysis did not show any significant differences between the implants at any healing time. The control implant showed a tendency of more newly formed bone after 4 weeks of healing and significantly higher bone area values after 9 weeks of healing. According to the results from this present study, both control and nano-HA surfaces were biocompatible and osteoconductive. A submicron thick coating of hydroxyapatite nanocrystals deposited onto blasted and acid etched screw shaped titanium implants did not enhance bone healing, as compared to blasted and etched control implants when placed in trabecular bone.
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