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8 results on '"Mattila, Riina"'

3. AEC and added filtration impacts to patient dose and image quality in sinus imaging

Author

Mattila, Riina

Subjects
Head and neck, genetic structures, education, Digital radiography, Radiation effects, Kv imaging
Abstract

Learning objectives Background Findings and procedure details Conclusion Personal information References, Learning objectives: Our objective is to learn how added filtration affects to patient dose and image quality in sinus imaging when using AEC (Automatic Exposure Control). We focused especially on differences between added filtration of 2mm Al and 0,1mm...

Published
2017
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6. Local delivery of a selective androgen receptor modulator failed as an anabolic agent in a rat bone marrow ablation model.

Author

Aro, Hannu T, Kulkova, Julia, Moritz, Niko, Kähkönen, Esa, and Mattila, Riina H

Subjects
HORMONE antagonists, ANIMAL experimentation, BONE marrow, BONE growth, DOSE-effect relationship in pharmacology, RATS, TIBIA, TOMOGRAPHY, TREATMENT effectiveness, ABLATION techniques, ANDROGEN receptors, THERAPEUTICS
Abstract

Background and purpose —Selective androgen receptor modulators (SARMs) have been developed to have systemic anabolic effects on bones and muscles without the adverse effects of steroidal androgens. One unexplored therapeutic option is the targeted application of SARMs for the enhancement of local new bone formation. We evaluated the osteogenic efficacy of a locally released SARM (ORM-11984). Methods —ORM-11984 was mixed with a copolymer of L-lactide and ɛ-caprolactone (PLCL). An in vitro dissolution test confirmed the sustainable release of ORM-11984 from the matrix. A bone marrow ablation model was used in female Sprague-Dawley rats. Implants containing 10%, 30%, or 50% ORM-11984 by weight or pure PLCL were inserted into the medullary canal of the ablated tibia. At 6 and 12 weeks, the volume of intramedullary new bone and the perimeter of bone-implant contact were measured by micro-computed tomography and histomorphometry. Results —Contrary to our hypothesis, there was a negative correlation between the amount of new bone around the implant and the dose of ORM-11984. There was only a mild (and not statistically significant) enhancement of bone formation in ablated bones subjected to the lowest dose of the SARM (10%). Interpretation —This study suggests that intramedullary/endosteal osteogenesis had a negative, dose-dependent response to locally released SARM. This result highlights the complexity of androgenic effects on bones and also suggests that there are biological limits to the targeted local application of SARMs. [ABSTRACT FROM PUBLISHER]

Published
2015
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7. Hydroxyapatite and bioactive glass surfaces for fiber reinforced composite implants via surface ablation by Excimer laser

Author

Hannu Huhtinen, Ivan Donati, Riina Mattila, Niko Moritz, Sergio Paoletti, Julia Kulkova, Pekka K. Vallittu, Eleonora Marsich, Kulkova, Julia, Moritz, Niko, Huhtinen, Hannu, Mattila, Riina, Donati, Ivan, Marsich, Eleonora, Paoletti, Sergio, and Vallittu, Pekka K.

Subjects
Ceramics, Scanning electron microscope, Prostheses and Implant, medicine.medical_treatment, Surface Propertie, Glass fiber, 02 engineering and technology, law.invention, 0302 clinical medicine, law, ta318, Scanning, Ceramic, Composite material, Microstructure, Composites, Microscopy, Tumor, Excimer laser, Prostheses and Implants, 021001 nanoscience & nanotechnology, Surfaces, Surface, Mechanics of Materials, visual_art, Bioactive glass, visual_art.visual_art_medium, Electron microscopy, Cell Line, Tumor, Cell Proliferation, Humans, Microscopy, Electron, Scanning, Porosity, Surface Properties, Durapatite, Glass, Lasers, Excimer, Biomaterials, Biomedical Engineering, 0210 nano-technology, Human, Materials science, ta220, Composite, Electron, Osseointegration, Cell Line, 03 medical and health sciences, Excimer, medicine, ta313, Lasers, Titanium alloy, 030206 dentistry, Biomaterial, Gla
Abstract

In skeletal reconstructions, composites, such as bisphenol-A-glycidyldimethacrylate resin reinforced with glass fibers, are potentially useful alternatives to metallic implants. Recently, we reported a novel method to prepare bioactive surfaces for these composites. Surface etching by Excimer laser was used to expose bioactive glass granules embedded in the resin. The purpose of this study was to analyze two types of bioactive surfaces created by this technique. The surfaces contained bioactive glass and hydroxyapatite granules. The selected processing parameters were adequate for the creation of the surfaces. However, the use of porous hydroxyapatite prevented the complete exposure the granules. In cell culture, for bioactive glass coatings, the pattern of proliferation of MG63 cells was comparable to that in the positive control group (Ti6Al4V) while inferior cell proliferation was observed on the surfaces containing hydroxyapatite granules. Scanning electron microscopy revealed osteointegration of implants with both types of surfaces. The technique is suitable for the exposure of solid bioactive glass granules. However, the long-term performance of the surfaces needs further assessment.

Published
2017

8. Bioactive glass surface for fiber reinforced composite implants via surface etching by Excimer laser

Author

Hannu Huhtinen, Ivan Donati, Pekka K. Vallittu, Niko Moritz, Sergio Paoletti, Julia Kulkova, Riina Mattila, Eleonora Marsich, Kulkova, Julia, Moritz, Niko, Huhtinen, Hannu, Mattila, Riina, Donati, Ivan, Marsich, Eleonora, Paoletti, Sergio, and Vallittu, Pekka K.

Subjects
Calcium Phosphates, Materials science, Bone Regeneration, Surface Properties, medicine.medical_treatment, Simulated body fluid, Biomedical Engineering, Biophysics, Bioactive glass, Bisphenol-A-glycidyldimethacrylate, Excimer laser, Fiber-reinforced composites, Implant, Intramedullary nail, Laser ablation, UV laser, Bioactive gla, Biocompatible Materials, 02 engineering and technology, Fiber-reinforced composite, Osseointegration, law.invention, Cell Line, 03 medical and health sciences, 0302 clinical medicine, law, Materials Testing, medicine, ta318, Surface layer, Composite material, Bone regeneration, Cell Proliferation, ta313, 030206 dentistry, Prostheses and Implants, 021001 nanoscience & nanotechnology, Lasers, Excimer, Glass, 0210 nano-technology
Abstract

Biostable fiber-reinforced composites (FRC) prepared from bisphenol-A-glycidyldimethacrylate (BisGMA)-based thermosets reinforced with E-glass fibers are promising alternatives to metallic implants due to the excellent fatigue resistance and the mechanical properties matching those of bone. Bioactive glass (BG) granules can be incorporated within the polymer matrix to improve the osteointegration of the FRC implants. However, the creation of a viable surface layer using BG granules is technically challenging. In this study, we investigated the potential of Excimer laser ablation to achieve the selective removal of the matrix to expose the surface of BG granules. A UV-vis spectroscopic study was carried out to investigate the differences in the penetration of light in the thermoset matrix and BG. Thereafter, optimal Excimer laser ablation parameters were established. The formation of a calcium phosphate (CaP) layer on the surface of the laser-ablated specimens was verified in simulated body fluid (SBF). In addition, the proliferation of MG63 cells on the surfaces of the laser-ablated specimens was investigated. For the laser-ablated specimens, the pattern of proliferation of MG63 cells was comparable to that in the positive control group (Ti6Al4V). We concluded that Excimer laser ablation has potential for the creation of a bioactive surface on FRC-implants.

Published
2015

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