@article{HeiligSandnerJordanetal.2021,
  author    = {Heilig, Philipp and Sandner, Phoebe and Jordan, Martin Cornelius and Jakubietz, Rafael Gregor and Meffert, Rainer Heribert and Gbureck, Uwe and Hoelscher-Doht, Stefanie},
  title     = {Experimental drillable magnesium phosphate cement is a promising alternative to conventional bone cements},
  series = {Materials},
  volume    = {14},
  journal   = {Materials},
  number    = {8},
  issn      = {1996-1944},
  doi       = {10.3390/ma14081925},
  url       = {http://nbn-resolving.de/urn:nbn:de:bvb:20-opus-236633},
  year      = {2021},
  abstract  = {Clinically used mineral bone cements lack high strength values, absorbability and drillability. Therefore, magnesium phosphate cements have recently received increasing attention as they unify a high mechanical performance with presumed degradation in vivo. To obtain a drillable cement formulation, farringtonite (Mg\(_3\)(PO\(_4\))\(_2\)) and magnesium oxide (MgO) were modified with the setting retardant phytic acid (C\(_6\)H\(_{18}\)O\(_{24}\)P\(_6\)). In a pre-testing series, 13 different compositions of magnesium phosphate cements were analyzed concentrating on the clinical demands for application. Of these 13 composites, two cement formulations with different phytic acid content (22.5 wt\% and 25 wt\%) were identified to meet clinical demands. Both formulations were evaluated in terms of setting time, injectability, compressive strength, screw pullout tests and biomechanical tests in a clinically relevant fracture model. The cements were used as bone filler of a metaphyseal bone defect alone, and in combination with screws drilled through the cement. Both formulations achieved a setting time of 5 min 30 s and an injectability of 100\%. Compressive strength was shown to be ~12-13 MPa and the overall displacement of the reduced fracture was <2 mm with and without screws. Maximum load until reduced fracture failure was ~2600 N for the cements only and ~3800 N for the combination with screws. Two new compositions of magnesium phosphate cements revealed high strength in clinically relevant biomechanical test set-ups and add clinically desired characteristics to its strength such as injectability and drillability.},
  language  = {en}
}
@article{GoetzHoleczekGrolletal.2021,
  author    = {G{\"o}tz, Lisa-Marie and Holeczek, Katharina and Groll, J{\"u}rgen and J{\"u}ngst, Tomasz and Gbureck, Uwe},
  title     = {Extrusion-Based 3D Printing of Calcium Magnesium Phosphate Cement Pastes for Degradable Bone Implants},
  series = {Materials},
  volume    = {14},
  journal   = {Materials},
  number    = {18},
  issn      = {1996-1944},
  doi       = {10.3390/ma14185197},
  url       = {http://nbn-resolving.de/urn:nbn:de:bvb:20-opus-246110},
  year      = {2021},
  abstract  = {This study aimed to develop printable calcium magnesium phosphate pastes that harden by immersion in ammonium phosphate solution post-printing. Besides the main mineral compound, biocompatible ceramic, magnesium oxide and hydroxypropylmethylcellulose (HPMC) were the crucial components. Two pastes with different powder to liquid ratios of 1.35 g/mL and 1.93 g/mL were characterized regarding their rheological properties. Here, ageing over the course of 24 h showed an increase in viscosity and extrusion force, which was attributed to structural changes in HPMC as well as the formation of magnesium hydroxide by hydration of MgO. The pastes enabled printing of porous scaffolds with good dimensional stability and enabled a setting reaction to struvite when immersed in ammonium phosphate solution. Mechanical performance under compression was approx. 8-20 MPa as a monolithic structure and 1.6-3.0 MPa for printed macroporous scaffolds, depending on parameters such as powder to liquid ratio, ageing time, strand thickness and distance.},
  language  = {en}
}
@article{BruecknerMeiningerGrolletal.2019,
  author    = {Br{\"u}ckner, Theresa and Meininger, Markus and Groll, J{\"u}rgen and K{\"u}bler, Alexander C. and Gbureck, Uwe},
  title     = {Magnesium Phosphate Cement as Mineral Bone Adhesive},
  series = {Materials},
  volume    = {12},
  journal   = {Materials},
  number    = {23},
  issn      = {1996-1944},
  doi       = {10.3390/ma12233819},
  url       = {http://nbn-resolving.de/urn:nbn:de:bvb:20-opus-193052},
  year      = {2019},
  abstract  = {Mineral bone cements were actually not developed for their application as bone-bonding agents, but as bone void fillers. In particular, calcium phosphate cements (CPC) are considered to be unsuitable for that application, particularly under moist conditions. Here, we showed the ex vivo ability of different magnesium phosphate cements (MPC) to adhere on bovine cortical bone substrates. The cements were obtained from a mixture of farringtonite (Mg\(_3\)(PO\(_4\))\(_2\)) with different amounts of phytic acid (C\(_6\)H\(_{18}\)O\(_{24}\)P\(_6\), inositol hexaphosphate, IP6), whereas cement setting occurred by a chelation reaction between Mg\(^{2+}\) ions and IP6. We were able to show that cements with 25\% IP6 and a powder-to-liquid ratio (PLR) of 2.0 g/mL resulted in shear strengths of 0.81 ± 0.12 MPa on bone even after 7 d storage in aqueous conditions. The samples showed a mixed adhesive-cohesive failure with cement residues on the bone surface as indicated by scanning electron microscopy and energy-dispersive X-ray analysis. The presented material demonstrated appropriate bonding characteristics, which could enable a broadening of the mineral bone cements' application field to bone adhesives},
  language  = {en}
}