Genetic potential of interfacial guided osteogenesis in implant devices.

Department of Biochemistry, Faculty of Stomatology, University of Beograd, Beograd, Yugoslavia.
Dental Materials Journal (Impact Factor: 0.94). 07/2000; 19(2):99-132. DOI: 10.4012/dmj.19.99
Source: PubMed

ABSTRACT The purpose of this review is to summarise recent advances in the design and composition of bioactive surface layers of implantabile biomaterials, and thus the genetic potential of osteoprogenitor cells to recognize and respond to these diverse implanted biomaterials. Changes applied to a biomaterial's surface, in general, could improve its biocompatibility, osseointegration and durability properties, which are required for long-term implantation in the living body. In this review, the implant-bone interface was evaluated and interpreted on the basis of osteoblast cell cultures, i.e., on the genetic potential of osteoblasts to express different phenotype markers depending on the type of biomaterials used. The interface formed by in vitro-grown osteoblasts may be used to identify components of the in vivo implant-bone interface. Over the years, a large number of implant systems consisting of many different biomaterials have been introduced in dentistry and orthopaedics. This paper discusses the performance of currently used metals and other biomaterials, by focusing on the events which occur immediately after implantation and on their impact on the bone-implant interface. The review demonstrates that continuous improvements in composition, surface modality and design of implants may benefit osseointegration and clinical longevity of such implants. No load-bearing conditions or clinical status are discussed. Titanium (Ti) and calcium phosphate ceramics are regarded as the most biocompatible synthetic substances known to be used in hard tissue implantation. These biomaterials are osteoconductive, and do not induce ectopic bone formation. Nonetheless, they provide a physical matrix which is suitable for the deposition of new bone and may guide both the growth and extension of the bone. Comparative investigation evaluated that Ti implant systems appear to be apposed by more bone than ceramic systems, although alternatives concerning the type of Ti alloy and bioactive surface layer engineering, generate extremely diverse osseointegration results. Manufacturers have created an extensive range of inorganic or ceramic coatings on Ti implants in order to achieve better bone healing and osteoconduction. Biologically active molecules, added to the implant surface, represent breakthroughs in guided interfacial osteogenesis. This methodology offers an enormous potential of genetic controlling and promoting osteogenesis. The bone growth factors are not fully understood, but most researchers agree that the contact between the bioactive surface layer of the implant and bone is not static but dynamic and that the above factors may maximise the implant osseointegration.

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    ABSTRACT: Titanium (Ti) is currently the most widely used material for the manufacture of orthopedic and dental implants. Changes in the surface of commercial pure Ti (cp Ti) can determine the functional response of cells, and is therefore a critical factor for the success of the implant. However, the genotoxicity of titanium surfaces has been poorly studied. Thus, the purpose of this study was to evaluate the genotoxic potential of a new titanium surface developed by plasma treatment using argon-ion bombardment and compare it with an untreated titanium surface. Accordingly, comet assay, analysis of chromosomal aberrations (CAs), and Cytokinesis Block Micronucleus (CBMN) assay were carried out, using CHO-K1 (Chinese hamster ovary) cells grown on both titanium surfaces. Our results show that the untreated titanium surface caused a significant increase in % tail moment, in the number of cells with CAs, tetraploidy, micronucleus frequency, and other nuclear alterations when compared with the negative control and with the plasma-treated titanium surface. This difference may be attributed to increased surface roughness and changes in titanium oxide layer thickness.
    Toxicology 08/2009; DOI:10.1016/j.tox.2009.05.020 · 3.75 Impact Factor
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    ABSTRACT: The aim of the article is to present recent developments in material research with bisphenyl-polymer/carbon-fiber-reinforced composite that have produced highly influential results toward improving upon current titanium bone implant clinical osseointegration success. Titanium is now the standard intra-oral tooth root/bone implant material with biocompatible interface relationships that confer potential osseointegration. Titanium produces a TiO2 oxide surface layer reactively that can provide chemical bonding through various electron interactions as a possible explanation for biocompatibility. Nevertheless, titanium alloy implants produce corrosion particles and fail by mechanisms generally related to surface interaction on bone to promote an inflammation with fibrous aseptic loosening or infection that can require implant removal. Further, lowered oxygen concentrations from poor vasculature at a foreign metal surface interface promote a build-up of host-cell-related electrons as free radicals and proton acid that can encourage infection and inflammation to greatly influence implant failure. To provide improved osseointegration many different coating processes and alternate polymer matrix composite (PMC) solutions have been considered that supply new designing potential to possibly overcome problems with titanium bone implants. Now for important consideration, PMCs have decisive biofunctional fabrication possibilities while maintaining mechanical properties from addition of high-strengthening varied fiber-reinforcement and complex fillers/additives to include hydroxyapatite or antimicrobial incorporation through thermoset polymers that cure at low temperatures. Topics/issues reviewed in this manuscript include titanium corrosion, implant infection, coatings and the new epoxy/carbon-fiber implant results discussing osseointegration with biocompatibility related to nonpolar molecular attractions with secondary bonding, carbon fiber in vivo properties, electrical semiconductors, stress transfer, additives with low thermal PMC processing and new coating possibilities.
    12/2014; 4(4):549-569. DOI:10.3390/met4040549

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