Influence of porosity and pore size on the compressive strength of porous hydroxyapatite ceramic

1997 ◽  
Vol 23 (2) ◽  
pp. 135-139 ◽  
Author(s):  
Dean-Mo Liu
2018 ◽  
Vol 768 ◽  
pp. 135-139 ◽  
Author(s):  
Xin Yi Zhao ◽  
Xiao Peng Li ◽  
Kang Zhao ◽  
Yu Fei Tang

The objectives of this study are to prepare a porous hydroxyapatite ceramic which has dentin tubule-like structure and determine its permeability. Slurry of hydroxyapatite powder, deionized water and a binder was poured into a ring which was placed on a freezing plate.The hydroxyapatite slurry was freezed in a certain rate (by controlling the temperature of the freeze plate at −15°C, −30°C and −45°C) for a certain period of time, then the freezed sample was freezing dried to remove the frozen vehicle, followed by being sintered at 1250 °C for 2 h. After that,the morphology of the cross section and longitudinal section of the sintered porous hydroxyapatite ceramic was observed by SEM and the hydraulic conductance of cross section discs of the sintered porous hydroxyapatite were determined using a self-made micro-flowing permeability tester. Results showed that the prepared hydroxyapatite ceramics having bottom-up unidirectional comblike tubule structure and the tubule diameters associated with the temperature of freezing plate.The ceramic discs prepared on the freezing plate of −45°C exhibited similarity to nature dentin tubule, with a diameter of 9.72±3.41mm and a hydraulic conductance of 0.16±0.09 ml×min-1×cm-2×cm×H2O-1.


2019 ◽  
Vol 966 ◽  
pp. 145-150
Author(s):  
Siswanto ◽  
Dyah Hikmawati ◽  
Aminatun ◽  
Miranda Zamawi Ichsan

Synthesis of porous hydroxyapatite-collagen composites for bone implant applications has been carried out. Hydroxyapatite synthesized from coral by the precipitation method, while Collagen synthesized from chicken claws. Collagen formation was carried out by freeze-dry technique with variations in freezing time of 2, 4 and 6 hours at -80 ° C. The next process was by drying in a lyophilizer. Characterization of samples was carried out using Fourier Transform Infra Red (FTIR), Scanning Electron Microscopy (SEM), compressive strength test and cytotoxicity test with Microtetrazolium (MTT) assay. FTIR results proved that collagen uptake and hydroxyapatite combine chemically. This is indicated by the absorption of functional groups that did not coincide between collagen and hydroxyapatite functional groups with composites. SEM observations showed that the largest pore size was obtained at freezing for 2 hours which was 774 μm and the smallest in freezing for 6 hours was 640 μm. This pore size was an important parameter of the bone implant because it played a role in the osteoinductive process. The composite compressive strength test results for freezing 2 hours, 4 hours and 6 hours respectively was 737 KPa, 842 KPa and 707.7 KPa. The results of the cytotoxicity test with MTT showed the percentage of cell viability above 100%. This means that the Hydroxyapatite-collagen composite is non-toxic. So, the sample formed has qualified as a bone implant candidate.


2008 ◽  
Vol 103 (1) ◽  
pp. 66-71
Author(s):  
L. BERZINA-CIMDINA ◽  
R. SERZANE ◽  
I. SALMA ◽  
M. PILMANE ◽  
G. SALMS ◽  
...  

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