| 2691 Effects of Minor Elements on Dissolution of Calcium Phosphate Glasses | ||
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M.-C. KIM1, Y.-K. LEE1, K.-N. KIM2, S.-H. CHOI2, and R.Z. LEGEROS3, 1 Brain Korea 21 Project for Medical Science, Yonsei University, Seoul, South Korea, 2 Yonsei University College of Dentistry, Seoul, South Korea, 3 New York University College of Dentistry, USA Objectives: In order to understand the influence of the minor ions on the degradation and bone formability in calcium phosphate glasses, which is firstly proposed for dental crown and expected useful bone graft materials, dissolution rates and precipitation on the surface were observed at 37 degrees in Celsius. Methods: The minor ions used in this study were Na, K, Mg, F, Cl and Zn. Prior to the incorporation of the minor ions, calcium phosphate binary glasses with Ca to P ratios from 0.5 to 0.7 were prepared using calcium carbonate and phosphoric acid. They were crushed and mixed with the minor ions at various concentrations. They were remelted above 850 degrees in Celsius and reduced both powders and pellets. Powders lower than 40 microns and pellets with 10x10x2 mm were employed to the dissolution and precipitation tests, respectively. Dissolution rates were investigated in both acidic buffer solution with pH 3 and 7.3 and simulated body fluid. 25 mg powders were immersed into 50 ml solution. Degraded quantity was detected using Ca ion electrode. Each pellet was kept into both 15 ml of simulated body fluid and fetal bovine serum for 4 weeks. After each week, the surface of the pellets measured by XRD, IR and SEM. Results: Incorporation of Na, K and Mg caused increase of dissolution rate, while F, Cl and Zn brought decrease with significant difference. Crystalline phase and morphologies of the precipitation after exposure to SBF and FBS also related to either the species or amount of minor ions. Conclusions: These results indicated that the minor ions affect on degradation and bioreactivity of the calcium phosphate glass. Combination of these ions in certain quantity expected one of useful method to develop the synthetic bone-graft materials. Supported by the Korea Ministry of Health and Welfare, Grant No. 01-PJ5-PG3-20507-0105. | ||
| Seq #272 - Properties of Implants, Tooth Structure and Other Materials 11:00 AM-12:15 PM, Saturday, 28 June 2003 Svenska Massan Exhibition Hall B | ||
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