TY - CONF A1 - Dombrowski, Felix T1 - Figuline and biodegradable bone-replacement cements with different solubility: Mechanical behaviour during setting reaction and after storage under physiological conditions T2 - Junior EUROMAT 2010 CY - Lausanne, Switzerland DA - 2010-07-26 PY - 2010 AN - OPUS4-22516 LA - deu AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Dombrowski, Felix A1 - Marx, Heidi A1 - Ploska, Ute A1 - Nicolaides, Dagmar A1 - Stiller, M. A1 - Knabe, C. A1 - Berger, Georg T1 - Solubility and ingrowth behaviour of degradable and figuline calcium alkaline phosphate cements N2 - The thrust of the investigations presented here is to point out the degradation behaviour in vitro and the ingrowth behaviour in vivo of four different calcium alkaline phosphate cements. Two of the figuline and mouldable composites consist of the crystalline phase Ca2KNa(PO4)2 and two of the crystalline phase Ca10[K/Na](PO4)2 each containing 2wt% medium gel strength porcine gelatin. Furthermore A-TCP was added to both Ca10[K/Na](PO4)2 cements as a hardening supporting reactant. The testing material groups differ in small amorphous portions containing either silica phosphate (GB9), magnesium potassium phosphate (GB14) or diphosphates (401545 and 401545(70)). The respective composites show a monomodal particle size distribution (d50~7µm; span~4) and an average total porosity around 28vol%.For the solubility studies cylindrical samples (d=6mm; h=12mm) were stored in a 0.1mol TRIS buffer solution and incubated at 37°C for maximum 50 weeks. The storage solution was analysed and renewed every week. The results are plotted cumulative. For the in vivo studies critical size defects were dissected to mandibles in a sheep model in which a 1cm³ area of the bottom of the mandibles was surgically resected and replaced with the figuline cements whereas the mouldability allows the reconstruction of the original outer contour without draining off even when replacing upside down. KW - Calcium alkaline phosphate cement KW - Gelatin KW - Figuline KW - Solubility KW - Ingrowth behavior PY - 2012 DO - https://doi.org/10.4028/www.scientific.net/KEM.493-494.387 SN - 1013-9826 VL - 493-494 SP - 387 EP - 390 PB - Trans Tech Publ. CY - Aedermannsdorf AN - OPUS4-24924 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Dombrowski, Felix A1 - Hoffmann, Rita A1 - Ploska, Ute A1 - Marx, Heidi A1 - Berger, Georg T1 - Investigations on degradable and figuline calcium alkaline phosphate cements with multimodal particle size distribution N2 - The paper presented here deals with rheological and hardening properties during the setting reaction, and density and compressive strength after the final setting of a figuline composite consisting of Ca2KNa(PO4)2 and 2wt% medium gel strength gelatin. Compared to the composite with monomodal particle size distribution (d50=7.18µm; span=3.9) and its properties during and after setting reaction, the goal of this work is to increase the resulting product compressive strength by mixing different particle sizes in order to obtain bi- and trimodal distributions. For the bimodal powder mixtures the ratio in diameter (dcourse/dsmall) was chosen with 7/1 and volume ratio dcourse/dsmall was 70/30%. For the trimodal powder mixtures the ratio in diameter (dcourse/dmedium/dsmall) was chosen with 70/7/1 and volume ratio dcourse/dmedium/dsmall was set to 44/28/28%.After establishing an adequate crushing and sieving process the tap density and powder density of each fraction was determined. Subsequently, the different particle sizes were mixed and the densities and the Hausner ratio were determined again. The mixtures show an increase in both densities especially the tap density increased significantly. Rheological investigations show that the graphs of storage and loss moduli of the multimodal powder mixtures respectively are similar. The characteristic setting times show a slight decrease compared with the monomodal composite but not significantly different data. When comparing the resulting compressive strength of cylindrical samples, which were stored direct after reaching the initial setting time under physiological conditions, the studies illustrated in all cases for the multimodal mixtures a significant increase in compressive strength and a higher density. KW - Calcium alkaline phosphate cement KW - Gelatin KW - Compressive strength KW - Figuline KW - Particle size PY - 2012 DO - https://doi.org/10.4028/www.scientific.net/KEM.493-494.355 SN - 1013-9826 VL - 493-494 SP - 355 EP - 360 PB - Trans Tech Publ. CY - Aedermannsdorf AN - OPUS4-24925 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Dombrowski, Felix T1 - Investigations on degradable and figuline calcium alkaline phosphate cements with multimodal particle size distribution T2 - Bioceramics 23, 23rd. Anual Meeting of Intern. Soc. for Ceramics in Medicine (ISCM) CY - Istanbul, Turkey DA - 2011-11-04 PY - 2011 AN - OPUS4-24861 LA - deu AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Dombrowski, Felix T1 - Solubility and ingrowth behavior of degradable and figuline calcium alkaline phosphate cements T2 - Bioceramics 23, 23rd. Anual Meeting of Intern. Soc. for Ceramics in Medicine (ISCM) CY - Istanbul, Turkey DA - 2011-11-04 PY - 2011 AN - OPUS4-24862 LA - deu AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Dombrowski, Felix T1 - 3-D printed bioactive bone replacement scaffolds of alkali substituted orthophosphates containing meta- and di-phosphates T2 - Bioceramics24, ISCM CY - Fukuoka, Japan DA - 2012-10-21 PY - 2012 AN - OPUS4-26905 LA - deu AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Dombrowski, Felix A1 - Garcia Caso, P.W. A1 - Laschke, M.W. A1 - Klein, M. A1 - Günster, Jens A1 - Berger, Georg T1 - 3-D printed bioactive bone replacement scaffolds of alkaline substituted ortho-phosphates containing meta- and di-phosphates N2 - The paper presented here deals with the investigations of orthophosphates (Q0) containing none or differing amounts of meta-(Q2) and diphosphate phases (Q1) for the use of 3-dimensional printing process in order to create porous, bioactive, nonloadbearing bone replacement scaffolds. The main ceramic phase in all cases is Ca10[K/Na](PO4)7 hereinafter called 401545(100) consisting of 99,9% Q0 and 0,1% Q1-phase. The other phosphate ceramics i) 401545(40) consists of 75% Q0-phase, 22% Q1-phase and 4% Q2-phase ii) 401545(15) consists of 65% Q0-phase, 33% Q1-phase and 2% Q2-phase iii) 401545consists of 56% Q0-phase, 40% Q1-phase and 4% Q2-phase. The in-house produced ceramics where crushed and sieved to achieve particles of irregular shape in the range of 45-90µm. These powders show a quite good flowability and were used to generate cylindrical samples with a diameter of 5,5mm and a height of 11mm via 3-dimensional printing using a R1 printer from ProMetal company (USA). After drying the samples at T=125°C for 48 hours they were sintered at temperatures according to the thermal analysis results in the range of 900°C up to 1300°C. Afterwards the porosity, the linear shrinkage and the compressive strength were determined. KW - Calcium alkaline phosphates KW - 3-D printing KW - Porosity KW - Compressive strength PY - 2013 DO - https://doi.org/10.4028/www.scientific.net/KEM.529-530.138 SN - 1013-9826 VL - 529-530 SP - 138 EP - 142 PB - Trans Tech Publ. CY - Aedermannsdorf AN - OPUS4-26972 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Dreßler, Martin A1 - Dombrowski, Felix A1 - Simon, Ulla A1 - Börnstein, Julian A1 - Hodoroaba, Vasile-Dan A1 - Feigl, Michael A1 - Grunow, Sabrina A1 - Gildenhaar, Renate A1 - Neumann, Martin T1 - Influence of gelatine coatings on compressive strength of porous hydroxyapatite ceramics N2 - Porous ceramics prepared by the foam replication technique have a high porosity and low mechanical stability. It has been reported that coating such porous ceramics with gelatin allows for an improved compressive strength. Little details regarding the influence of important gelatin parameters such as concentration, temperature and drying conditions as well as bloom number which is a measure of the gel rigidity, on this toughening effect are available. This paper investigates the influence of these parameters on compressive strength of gelatin coated porous hydroxyapatite ceramics. It was found that concentration in the gelatin sols has a marked impact whereas sol temperature, bloom number and differing conditions during subsequent drying have only little influence on the compressive strength of the coated ceramics. KW - Films KW - Composites KW - Strength KW - Apatite KW - Biomedical application PY - 2011 DO - https://doi.org/10.1016/j.jeurceramsoc.2010.11.004 SN - 0955-2219 SN - 1873-619X VL - 31 IS - 4 SP - 523 EP - 529 PB - Elsevier Ltd. CY - Oxford AN - OPUS4-23216 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER -