PROFESSOR CHRISTINE KNABE-DUCHEYNE Adaptable dentistry Professor Christine Knabe-Ducheyne offers some details into her work researching new materials for dental bone augmentation which can be tailored for specifi c clinical applications Which smart biomaterials are you them into large segmental defects in investigating in particular, and what makes laboratory animals in order to achieve bone them so advantageous towards bone repair of these defects, which typically are regeneration? extremely diffi cult to repair. Our research focuses on interdisciplinary In separate studies, synchrotron-based translational research regarding smart microcomputer tomography has facilitated bioactive resorbable calcium alkali 3D visualisation and volumetric analysis of phosphate-based biomaterials for bone the newly formed bone tissue as well as of the regeneration and bone tissue engineering degrading bioceramics in biopsies harvested from applications. These materials have a patients at dental implant placement six months greater stimulatory effect on bone cell after sinus fl oor augmentation with tricalcium differentiation and bone tissue formation phosphate and in specimens harvested from compared to clinically established bone sheep, at a very high resolution of below 1 μm. grafting materials, in combination with a higher biodegradability. Contact of these How are you looking to disseminate your With regards to implants, how have clinical materials with body fl uids leads to surface research results and what applications are areas such as dentistry and orthopaedics transformation events involving dissolution you hoping your fi ndings will have? evolved? and reprecipitation which lead to silicon release, calcium uptake and protein We are disseminating our research results by There has been a signifi cant increase in dental adsorption. Bone cells adhere to these presenting them at international scientifi c implants and in alveolar ridge augmentation transformed surfaces via specifi c cell surface meetings and publishing them in the leading procedures, which has led to an ever- receptors and as a result they facilitate faster journals of the biomaterials fi eld and increasing demand for adequate bone grafting bone regeneration and repair. respective textbooks including Comprehensive materials. In addition, with the increased use Biomaterials , a major reference work covering of osseointegrated dental implants and with Are you currently using any unique methods all major aspects of biomaterials research. many implants functioning for a long time, the to gather your research? Could you briefl y We hope that our fi ndings will contribute to treatment of peri-implant bone loss due to discuss your team’s use of computer providing a range of smart bioactive bone infection has gained increasing importance. tomography in relation to bone formation? grafting materials and therapeutic strategies for patient care, materials which are optimally Although autogenous bone grafts are We currently develop therapeutic strategies tailored for various clinical applications currently the standard of care, bone which facilitate bone tissue engineering and whose effi cacy has been proven in an substitute materials are extensively studied of large segmental defects. It involves evidenced-based manner. in order to avoid harvesting autogenous fabricating 3D structures of these calcium bone. As a result, there has been heightened alkali phosphate materials by 3D printing. Are you looking to focus your research demand and an ongoing search for synthetic, We then also use mesenchymal stem cells efforts elsewhere in the near future? biodegradable bone substitute materials that and microvascular techniques for adequate facilitate bone repair and replacement by fully blood vessel formation. We utilise a perfusion An important component of our research functional bone tissue. bioreactor to cultivate mesenchymal stem increasingly involves bioactive sol-gel based cells within these scaffolds prior to implanting materials, which feature controlled and 66 INTERNATIONAL INNOVATION
PROFESSOR CHRISTINE KNABE-DUCHEYNE Smarter bioceramics Work is currently underway at Philipps-Universität Marburg in Germany to develop smart, rapidly resorbable bioceramics for bone regeneration in regenerative medicine and implant dentistry THE USE OF oral implants has become a common treatment to replace missing or lost teeth. However, when teeth are missing, the surrounding bone and soft tissue can break down as a result of the natural resorptive process. This creates a condition that must be treated, since the requirements for the design of implant superstructures, rather than the bone volume available, dictate the position in which the dental implants have to be placed. Thus, the resorption of the alveolar ridge after tooth extraction oftentimes necessitates that the site is developed by bone and soft tissue augmentation before implant placement. In orthopedics, 80 per cent of fractures that are treated with FIGURE 1. 3D-CALCIUM ALKALI PHOSPHATE osteosynthetic materials require adjuvant grafting SCAFFOLDS FOR BONE TISSUE ENGINEERING in the US. FIGURE 2. HISTOMICROGRAPH OF NEWLY FORMED BONE AND DEGRADING CALCIUM ALKALI Currently, autogenous bone grafts are mostly PHOSPHATE GRANULE. tailored release of various molecules such used for bone reconstruction in orthopedics and as antibiotics and factors that inhibit bone cranio-maxillofacial surgery. Bone is harvested stimulating osseous apposition to the implant resorbing cells, namely osteoclasts. These from a donor site located in a different area of the surface, thereby promoting a rapid fi xation of the materials are designed and specifi cally patient’s body. Among the various techniques to devices to the skeleton. tailored to treat chronic infl ammatory bone reconstruct or enlarge a defi cient alveolar ridge, loss conditions resulting from infections guided bone regeneration (GBR) and sinus fl oor BIOACTIVE CERAMICS which are hard to eradicate. This addresses augmentation procedures have become well- a number of clinical conditions for which established surgical approaches. Autogenous Numerous bone grafting materials have been therapies with predictable success rates bone grafts are usually combined with barrier developed and studied since the late 1970s. The do not exist such as refractory infrabony membranes. These autografts have been used majority of these grafting materials are calcium defects in periodontitis, periimplantitis, to reduce the defect volume, thereby stabilising phosphate-based materials. The bioactive ceramics osteomyelitis, periprosthetic infections and the blood clot, and to support the membrane as most commonly investigated for use in bone prevention thereof. In this context we deal a space-maintaining device, thus preventing their regeneration are β -tricalcium phosphate ( β -TCP), with interdisciplinary research involving the collapse into large defects. hydroxyapatite (HA), and bioactive glasses such fi elds of implant dentistry, craniofacial bone as bioactive glass 45S5 (BG45S5). All of these regeneration, periodontology, orthopaedics materials are biocompatible and osteoconductive. BONE SUBSTITUTES and traumatology. However, they differ considerably in the rate of The use of autogenous bone, however, has several resorption. Would you like to discuss any other aspects of disadvantages: the need for an additional surgical your work? site, donor site morbidity exceeding that at the A biomaterial used as a bone substitute should treatment site, insuffi cient volume of harvested be a temporary material serving as a scaffold for We are also studying the effect of gender, bone, and the need for general anaesthesia to bone remodelling. The material must degrade age and hormone status on bone formation harvest extraoral bone. These problems have led to in a controlled fashion into nontoxic products after sinus fl oor augmentation with extensive research into bone substitute materials. that the body can metabolise or excrete via tricalcium phosphate with the goal of Professor Christine Knabe-Ducheyne from the normal physiological mechanisms. Moreover, identifying parameters which can be used as Philipps-Universität Marburg, Germany, is leading this substance should be resorbable and should predictive tools for indicating how fast bone a team of researchers who are investigating the use regeneration will proceed in a given patient. of smart, rapidly resorbable bioceramics for use in FIGURE 3 . HISTOMICROGRAPH OF CALCIUM ALKALI This will help with determining the ideal time regenerative medicine and implant dentistry. PHOSPHATE INDUCING NEW BONE FORMATION AT for re-entering the site and placing the dental ITS SURFACE implants, and is an effort towards creating “Among alternative graft choices, synthetic bone personalised medicine. substitutes are superior to freeze-dried human allografts or bovine-deproteinised bone xenografts in several respects,” Knabe-Ducheyne explains. “They excel in terms of safety profi le, as there is no risk of disease transmission or immunological challenges.” The ability to bond to bone tissue and stimulate bone formation at their surface is a unique property of bioactive ceramics. They are used as bone grafting materials and as coatings for titanium and its alloy. These coatings have been shown to accelerate initial stabilisation of implants by enhancing bony ingrowth and WWW.RESEARCHMEDIA.EU 67
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