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- 2012 (2) (entfernen)
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- Englisch (2)
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- 3D printing (1)
- Calcium alkaline phosphate cement (1)
- Calcium alkaline phosphates (1)
- Ceramic scaffolds (1)
- Figuline (1)
- Gelatin (1)
- Ingrowth behavior (1)
- Oral surgery (1)
- Solubility (1)
Solubility and ingrowth behaviour of degradable and figuline calcium alkaline phosphate cements
(2012)
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.
Calcium alkaline phosphate scaffolds for bone regeneration 3D-fabricated by additive manufacturing
(2012)
Calcium alkaline phosphate granulates can be used for substitution of several bone defects but for the reconstruction of large skeletal parts in the maxillofacial and orthopaedic fields fitted scaffolds are preferable. Within the additive manufacturing methods, the 3D printing process offers exciting opportunities to generate defined porous scaffolds. We used a R1 printer from ProMetal Company, USA, for producing scaffolds directly from a ceramic powder. For this direct free form fabrication technology the powder has to possess a lot of specific properties both for the generation of a stable green body and also for the subsequent sintering preparation. For this printing process we prepared different granules in a fluidized bed process containing Ca2KNa(PO4)2 as main crystalline phase. Granules were characterized by different methods and several sieve fractions were used for preparing disc like and cylindrical parts. The suitability of granules for this printing process was determined by porosity and strength of produced bodies. Next to granules' performance both of these properties can be directly influenced by 3D printing process parameters. With knowledge of suitable process parameters scaffolds with different porosity in a respective desired design can be created. In this study, cylindrical scaffolds with graded porosity were produced for bone regeneration of segmental defects in maxillofacial surgery and dental implantology by tissue engineering.