Papers by Author: Sang Bae Kim

Abstract: In the present work, surface treatment of surgical implant Titanium alloy with micro bioactive nanotube was experimented. Surface treatment of Ti-6Al-4V bio-implant carried out by giving alkali hydrothermal and heat treatment. The specimens were treated in 1M NaOH at 100, 150, 200°C for different holding time of 2 hr, 4 hr, 6hr, 12 hr, 24hr & 48 hr. The hydrogel layer generated during the alkali treatment was crystallized to sodium titanate (Na2Ti6O13) and resulted into the formation of nano sized tubes on heat treatment. X-ray Diffractrometry (XRD), Scanning Electron Microscopy (SEM) and Transmission Electron Microscopy (TEM) revealed the different phases and surface morphology of these nanorods. The biocompatibility test done using Simulate Body Fluid (SBF) showed that the Hydroxyapatite (HAp) was well formed at the sodium titanate nanotube layer generated on the Ti-6Al-4V specimen. The best condition for this increase in surface biocompatibility was optimized to 6 hours hydrothermal treatment under 200°C using 1 M NaOH followed by 1 hour heat treatment at 600°C.

Abstract: In order to overcome the disadvantage of commercialized PMMA bone cement, we have developed novel PMMA-based bone cement(7P3S) reinforced by 30 wt.% of bioactive CaO-SiO2 gel powders to induce the bioactivity as well as to increase mechanical property for the PMMA bone cement. The novel 7P3S bone cement hardened after mixing for about 7 minutes. For in vitro evaluation, apatite forming ability of it was investigated using SBF. When the novel 7P3S bone cement was soaked into SBF, it formed apatite on its surfaces within 1 week Furthermore; there is no decrease in its compressive strength within 9 weeks soaking in SBF. It is though that hardly decrease in compressive strength of 7P3S bone cement in SBF is due to the relative small amount of gel powder or its spherical shape and monosize. In vivo evaluation of the novel 7P3S bone cement was carried out using rabbit. After implantion into rabbit tibia for several periods, the interface between novel bone cement and natural bone was evaluated by CT images. According to the results, the novel bone cement directly contact to the natural bone without fibrous tissue after implantation for 4 weeks. This results indicates that the newly developed 7P3S bone cement can bond to the living bone and also be effectively used as bioactive bone cement without decrease in mechanical property.

Abstract: Novel PMMA-based bone cement using bioactive sol-gel derived CaO-SiO2 powder in order to induce bioactivity as well as to increase its mechanical property. The novel PMMA-based bone cements formed apatite on their surfaces in Simulated Body Fluid(SBF). In the present study, a change in mechanical property of the cement was evaluated using SBF. Before soaking in SBF, its compressive strength showed 80.6±2.1MPa. After soaking in SBF for 2 weeks, 8weeks and 9 weeks, its compressive strength were changed to 83.6±1.6MPa, 87.3±2.4MPa and 85.6±1.8MPa, respectively. It is clear that from the above result, there is no decrease in its compressive strength within 9 weeks soaking in SBF. That it hardly decreases in compressive strength of 7P3S bone cement in SBF is due to the relative small amount of gel powder or its spherical shape and monosize. Therefore, the newly developed PMMA-based cement can bond to the living bone and also be effectively used as bioactive bone cement without decrease in mechanical property.