The dental implant materials must have the biocompatibility and biofunctionalbility to maintain a stable function. Hydroxyapatite(HA) have been used as substitutes for bone restoration in oral and maxillofacial area. Since 1990, HA coated implants have been commonly used to enhance the osseointergration between implant surfaces, and the host bone tissues.
Before coating synthetic HA to titanium made by our laboratory, it was necessary to get the biocompatibility of them through in Vitro study. Animal osteoblastic or osteosarcoma cell lines was used to evalute the biocompatibility of dental implant, but these cell lines were quite different metabolism from normal osteoblast(NHost) to examine the biocompatibility of NHost onthe surface of dental implant materials. NHsts were cultured in DMEM containing 10% FBS, and observed by inverted and scanning electron microscope for attachment to the surface of synthetic HA and titanium. Growth curve, and adhesion assay according to 5, 10% FBS, repectively were done in Vitro study. For mineralization capablility, von Kossa staining was done, and SEM study was taken for cell attachment to dental implant materials. Ca, P and alkaline phosphatase concentration in medium was calculated during 4 weeks subculture, which was treated with Wilcoxon rank, Anova test and linear regression. The obtained result were as follows.
1. Doubling time of 3rd and 4th group was about 40 hours, which was longer than 2nd group. Inverted microscopic features showed Nhost cells with lone processes parallel and perpendicular to the surface of synthetic HA and titanium in early stage, which was colonized, and grew multilayered cellular arrangement at 4weeks.
2. Although adnesion assay of 3rd and 4th group were lower than 2nd titanium plate was higher than HA plate, it is not difficult of Nhosts to grow on the surface of HA and titanium plate.
3. Von Kossa staining showed mineralized nodules of 3rd and 4th group at 4th weeks, and as the same size and number as 2nd group.
4. Ca, P and ALP concentration of 2nd, 3rd and 4th group were gradully decreased showed significance through Wilcoxon and Anova test.
5. Linear analysis showed no change in Ca, P and ALP of 1st group according to time, but significantly correlation between Ca, P and ALP concentration, and time schedule in 2nd, 3rd and 4th group.
From the above results, growth and adhesion assay of NHost cell line of titanium plate were better than that of HA plate, but there was no difference about von Kossa mineralized nodule formation. Ca, P and ALP concentration of 2nd group was lower than that of the 3rd and 4th group according to time, which meant that although NHost cell line growth on HA and titanium was lower than that of 2nd group, this cell line knowed the biocompatatility of HA and titanium plate.
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