12 Works

Patterning of Versatile Nanocomposite Biomaterials based on Bioinert PEG-Hydrogels and Bioactive Nanohydroxyapatite and Cellular Responses to the Biointerfaces

Marga Cornelia Lensen, Axel Löbus & Zhenfang Zhang
Hydroxyapatite (HAp) is one of the most important bioceramics for medical and dental applications, as it possesses excellent biocompatibility and is osteoconductive. However, pure HAp is difficult to shape in the complex forms required for tissue engineering applications such as bone repair because of its hardness and brittleness. Therefore, we have developed novel nanocomposite hydrogels based on HAp and poly(ethylene glycol) (PEG) hydrogels. The gel properties (soft, hydrated and moldable) allow the fabrication of 2D-patterned...

Integration of high-resolution micro-computed tomography in the quality control of 3D-printed scaffolds.

Vincent A Stadelmann, Mike A Geven, Dirk W Grijpma, Geoff R Richards, David Eglin & Olivier Guillaume
Additive manufacturing, and among all stereolithography, has shown great potential in the field of biomedical science. This technology offers a relatively simple means to manufacture objects with complex external and internal features and high spatial resolution, compared to more traditional manufacturing methods. Successful clinical reports of patient specific implants manufactured using 3D printing foster great promises, particularly in the field of craniomaxillofacial reconstruction. However, along with the ability to produce highly defined prostheses, the community...

Corrosion behavior of dental CoCr alloys made by different digital workflow processes compared to cast CoCr alloys

Christine Schille, Ernst Schweizer & Jürgen Geis-Gerstorfer
Dental metallic restorations can be made alternatively by casting or CAD/CAM procedures such as milling and selective laser melting. This raises the question as to how far the material properties differ. The aim of this study was to evaluate the corrosion behavior of dental porcelain fused CoCr alloys manufactured by the CAD/CAM techniques using wet milling of solid blanks (Organic), dry milling of ‘wax-like’ blanks and subsequent sintering (Ceramill Sinron) and selective laser melting (Remanium...

Degradation behavior of as cast and powder metallurgy processed Mg-Ca alloys

Eshwara Phani Shubhakar Nidadavolu, Frank Feyerabend, Thomas Ebel, Regine Willumeit-Römer & Michael Dahms
Biodegradability and mechanical properties similar to natural bone have made Mg alloys potential competitors for metal implant applications. Mg-Ca alloys are of interest as Ca is an essential element in the human body. However, an increased Mg2Ca secondary phase with increasing Ca addition results in pitting corrosion in these alloys. Reports suggest that Mg alloys with ≤ 1wt % Ca additions possess good degradation resistance. Hence, Mg-xCa alloys (x= 0.3, 0.6, 0.9 wt %) were...

Mechanical properties of 3D printed water-soluble polyvinyl alcohol for maxillofacial prostheses prototypes

Jochen Kuttig, Phan Hai-Binh Bui, Alexey Unkovskiy, Christine Schille, Jürgen Geis-Gerstorfer & Sebastian Spintzyk
A digital workflow to produce maxillofacial prostheses could improve reproducibility and aesthetic outcomes. The possibility to 3D scan patients’ limbs is given, but there is no method established to produce the prostheses from this data. In this study, tests were performed and a protocol developed to print 3D objects from water-soluble polyvinyl alcohol (PVA) in consistent quality. Prototypes of maxillofacial prosthesis were fabricated (Figure 1). Those could be used to create molds for the casting...

Grindability analysis of dental core build-up materials under clinically relevant test procedure.

Tengku Ibrahim Maulana
Objective: Endodontically treated teeth often suffers a lack of coronal tooth structure, so that adding a suitable core build-up material is required, before the abutment tooth preparation and crown reconstruction can be performed. The core build-up material is the fundamental part of the load bearing structure of the tooth. Therefore, it needs to possess adequate mechanical and physical properties and has to support and protect the residual tooth structure before the final restauration. The grindability...

Mechanical Behavior of a Porous, Sub-total Meniscus Implant Based on Poly(trimethylene carbonate)

Bas Van Bochove, Tony Van Tienen, Pawel Tomaszewski, Gerjon Hannink, Nico Verdonschot, Pieter Buma & Dirk W Grijpma
Meniscus tears often occur in the avascular inner part of the meniscus and therefore do not heal spontaneously. Current treatments such as meniscectomy and the implantation of allografts are insufficient. In this study we prepared a designed, sub-total, porous meniscus implant from functionalized poly(trimethylene carbonate) by stereolithography, and investigated its mechanical behavior in a human cadaveric knee. The sub-total meniscus implant was sutured to the peripheral rim of the meniscus and placed in the medial...

The Effects of HAc Etching on the Degradation Behavior of Mg-5Gd

Marcjanna Maria Gawlik, Markus Steiner, Björn Wiese, Jorge González, Frank Feyerabend, Michael Dahms, Thomas Ebel & Regine Willumeit-Römer
The effects of different acetic acid (HAc) etching procedures were investigated using Mg-5Gd samples in as-extruded and T4 conditions in order to achieve defined surfaces and homogenous degradation behavior. Samples were dipped into HAc solution with five different concentrations for three durations. In total, fifteen different etching conditions were tested with regard to the degradation resistance in physiological solution. The cell culture medium consisted of Dulbecco's Modified Eagle Medium (DMEM), Glutamax, 10 Vol.-% fetal bovine...

Halloysite Nanotubes as Nanofillers to Reinforce Glass Ionomer Cements

James Holder, Lisa McNally & Michele Barbour
Glass ionomer cements (GICs) have many clinically favourable properties such as adhesion to tooth tissues and moisture tolerance, but have low strength compared with other direct dental restorative materials, and this limits their applications. Nanomaterials have shown promise in reinforcing biomaterials, including cements. The aim of this study was to explore whether the compressive strength of a GIC could be enhanced using halloysite nanotubes (HNTs), a naturally occurring hollow tubular material derived from clays. 1-15%...

Function and structure – Combined optical functionality and specific bio-interaction for multifunctional biomedical materials

Tina Sabel & Marga C. Lensen
Novel multifunctional biomedical materials are discussed, capable for the integration of optical functionality and exploiting the correlation of structure and function. Therefore, volume holographic structuring can be applied for the integration of three-dimensional optical structures with specific functionality in terms of diffractive properties. The strategy to combine optical structuring of the volume and specific modification of the surface is particularly discussed for the design of advanced intra-ocular lens implants. Based on a multifunctional biomedical material...

Effect of surface treatment with aluminum oxide and plasma spray on shear bond strength between veneering resins and ceramic filled PEEK versus glass filled PEEK: An in-vitro study

Mohamed Younis
In this study the effect of different surface treatments on the shear bond strength between PEEK and a composite resin was tested. Following ISO 10477 guidelines, two different PEEKs (ceramic & glass filled PEEK) were used by preparing 30 specimens of each type for 3 different surface treatment groups (reference, sandblasting and atmospheric plasma treatment). Bonding procedures started using visiolink adhesive followed by opaquer application then veneering resin. Surface roughness of the specimens was measured...

Cryogels as potential scaffolds for wound healing applications

Annika Wartenberg, Jürgen Weisser, Susanne Thein, Henri-Pierre Suso, Ralf Schmidt & Matthias Schnabelrauch
Various cryogels have been manufactured from methacrylated biopolymer-derived hyaluronan and dextran as well as from synthetic macromer polyethylene glycol diacrylate (PEGDA) with and without addition of egg shell membrane protein as potential mediator of the cell regeneration capacity of the final scaffolds. Among the studied crosslinkable macromers, PEGDA has been found to provide cryogels with excellent mechanical stability, inter-connecting porosity and an encouraging in vitro cytocompatibility. Furthermore, the addition of egg shell membrane protein particles...

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