{"product_id":"on-the-importance-of-nanometer-structures-for-implant-incorporation-in-bone-tissue","title":"On the importance of nanometer structures for implant incorporation in bone tissue","description":"Introduction\u003cbr\u003e\u003cbr\u003e Replacing lost teeth with dental implants is today a reliable treatment\u003cbr\u003e method associated with good long-term clinical results. Different\u003cbr\u003e surface modifications alter the surface topography at micro- and\u003cbr\u003e nanometer level of resolution as well as chemical properties, which\u003cbr\u003e have shown to be of importance for osseointegration. Research\u003cbr\u003e within the field of implantology is still intense and aims at further\u003cbr\u003e improving the implant properties to achieve successful treatments\u003cbr\u003e for patients with compromised bone as well as developing a surface\u003cbr\u003e that provides faster integration to shorten the treatment period.\u003cbr\u003e Furthermore, more basic science data is needed to increase our\u003cbr\u003e understanding of the mechanisms involved in osseointegration.\u003cbr\u003e The significance of the surface topography on the micrometer\u003cbr\u003e level for implant integration is well known. However, the knowledge\u003cbr\u003e of how and to what extent nanostructures may be of importance in\u003cbr\u003e early bonehealing and osseointegration remains to be investigated.\u003cbr\u003e\u003cbr\u003e Aim\u003cbr\u003e\u003cbr\u003e The overall aim of this thesis was to describe a technique to\u003cbr\u003e characterize commercial oral implants on the nanometer level when\u003cbr\u003e nanostructures are applied on a microroughness and to investigate\u003cbr\u003e whether or not the nanometer surface roughness was correlated to\u003cbr\u003e the more well-known micrometer roughnesss; to study the real-time\u003cbr\u003e initial cellular interactions of human osteoblasts and fibroblasts to\u003cbr\u003e different implant surfaces with and without a coat of nanocrystalline\u003cbr\u003e hydroxyapatite; and to evaluate the early bone response to a\u003cbr\u003e nanocrystalline hydroxyapatite coating (nano-HA) applied on\u003cbr\u003e smooth cylindrical and moderately rough screw-shaped implants. Materials and Methods\u003cbr\u003e Twelve different commercial screw-shaped dental implants with\u003cbr\u003e different surface modifications were examined using optical\u003cbr\u003e interferometry together with Gaussian digital filters and scanning\u003cbr\u003e electron microscopy (SEM). Human osteoblasts and fibroblasts\u003cbr\u003e were used when investigating the initial cell-surface interaction to\u003cbr\u003e different surfaces modifications with optical tweezers (OT) and\u003cbr\u003e quartz crystal balance with dissipation monitoring (QCM-D). To\u003cbr\u003e evaluate the effect of nanocrystalline hydroxyapatite (nano-HA)\u003cbr\u003e compared to nanosized particles of titanium in early bone response,\u003cbr\u003e smooth cylindrical titanium implants with no microroughness were\u003cbr\u003e inserted in rabbit tibia. The implant surfaces were examined using\u003cbr\u003e atomic force microscopy (AFM) and interferometry. To evaluate the\u003cbr\u003e biological response, histological analyses including bone contact\u003cbr\u003e (BIC) and bone area (BA), as well as qualitative analysis were\u003cbr\u003e performed. Furthermore, screw-shaped sandblasted and acid etched\u003cbr\u003e titanium implants coated with nano-HA of different thicknesses\u003cbr\u003e and un-coated controls were evaluated in rabbit tibia as well as\u003cbr\u003e femur. Interferometry, SEM and X-ray Photoelectron Spectroscopy\u003cbr\u003e (XPS) were used to characterize the implant surface topography and\u003cbr\u003e chemical composition. Biomechanical and histological evaluations\u003cbr\u003e including BA, newly formed bone and qualitative evaluations were\u003cbr\u003e performed.\u003cbr\u003e\u003cbr\u003e Results\u003cbr\u003e\u003cbr\u003e The studies showed that it is possible to characterize the surface\u003cbr\u003e nanoroughness of commercially dental implants using interferometry.\u003cbr\u003e A 1x1μm Gaussian filter was found useful to identify nanoroughness\u003cbr\u003e in terms of height deviation. It was demonstrated that the implants\u003cbr\u003e do have distinct roughness on the nanometer level of resolution and\u003cbr\u003e that the nanoroughness is not correlated to the microroughness\u003cbr\u003e when comparing mean surface roughness (Sa). Significant differences\u003cbr\u003e in Sa on the nanometer scale were found among some of the\u003cbr\u003e implants investigated. However, to detect specific nanostructures\u003cbr\u003e an additional SEM examination is necessary. The results from\u003cbr\u003e optical trap experiments showed that both osteoblasts and\u003cbr\u003e fibroblasts responded in a similar way towards most of the surfaces. No difference in initial cell attachment could be detected between\u003cbr\u003e the surfaces when using the QCM-D technique.\u003cbr\u003e A nano-HA coating applied on smooth cylindrical implants did\u003cbr\u003e not enhance bone responses in terms of bone contact (BIC) and bone\u003cbr\u003e area (BA) values as compared to nano-titania.\u003cbr\u003e Screw-shaped sandblasted and acid etched titanium implants\u003cbr\u003e with applied nanothick (~20nm) coating of nano-HA with similar Sa\u003cbr\u003e values on both micro- and nanometer scale of resolution presented\u003cbr\u003e similar removal torque values, BA values and showed similar\u003cbr\u003e amounts of newly formed bone as compared to un-coated controls\u003cbr\u003e when placed in cortical bone. The same result was demonstrated in\u003cbr\u003e trabecular bone with a submicron thick coating of nano-HA onto\u003cbr\u003e sandblasted and acid etched screw-shaped implants.\u003cbr\u003e\u003cbr\u003e Conclusions\u003cbr\u003e\u003cbr\u003e Within the limits of the studies in this thesis, it was demonstrated\u003cbr\u003e that commercially available oral implants do have nanoroughness\u003cbr\u003e of various amounts and that the nanoroughness is not correlated to\u003cbr\u003e the microroughness. It was demonstrated possible to observe cell attachment using\u003cbr\u003e optical trapping and QCM-D, however no obvious differences\u003cbr\u003e between the surfaces could be detected. A nano-HA coating applied on cylindrical titanium implants did not enhance early bone response compared to a nano-titania coating\u003cbr\u003e when evaluated in cortical bone. Furthermore, sandblasted and acid\u003cbr\u003e etched screw-shaped implants with applied coatings of different\u003cbr\u003e thicknesses of nano-HA perform similar as un-coated controls when\u003cbr\u003e evaluated in cortical and trabecular bone.","brand":"Malmö högskola","offers":[{"title":"Default Title","offer_id":31916916736089,"sku":"9789171043849","price":24.95,"currency_code":"EUR","in_stock":true}],"thumbnail_url":"\/\/cdn.shopify.com\/s\/files\/1\/0061\/0372\/8217\/files\/9789171043849_1-on-the-importance-of-nanometer-structures-for-implant-incorporation-in-bone-tissue.jpg?v=1749822751","url":"https:\/\/www.suomalainen.com\/products\/on-the-importance-of-nanometer-structures-for-implant-incorporation-in-bone-tissue","provider":"Suomalainen.com","version":"1.0","type":"link"}