The purpose of this study was to observe morphologically on the remodelling, bone induction and conduction of hydroxyapatite(HA) in hole(4㎜ diameter, 8㎜ depth) Of rabbit tibia. At 5 and 8 months, HA With bone tissve were fixed with 10% neutral formalin, dehydrated, and embedded with Spurr low viscosity resin. After the specimen was cut by 500㎛ with slow diamond wheel saw, these were grinded up to 100㎛ with grinder, examined with light and reflection electron microscope, and for qualitative detection of calcium and phosphate, EPMA(electron probe micron analysis) was used. The obtained results were as follows.
1. In toluidine blue staining of 5 months specimen, active bone formation were observed around resorbed synthetic HA and new bone formation between commercial HA. In another area hone formation around HA was well demarcated from compact bone.
2. In toluidine blue staining of 8 months specimen, embedded synthetic HA and conglomerated Hft was surrounded by irregular bone trabecula containing osteocytes. Commercial HA was more resorbed than that of 5 months, and bone formation between resorbed HA was seen. But bone formation in hole was not completed successfully.
3. In REM of 5 months resorbed synthetic HA showed higher mineralization than that of new bone. Conglomerated commercial HA was the same density to compact bone. In 8 months resorbed synthetic HA was attached to bone trabeculae and showed higher density. Commercial HA showed various bone density, but minor bone trabeculae between HA showed different bone density.
4. In EPMA, calcium and phosphate levels were increased in HA particles of both group, but there were many variations in surrounding bones.
From the above results, it was suggested that the commercial HA was resorbed faster and folmed good new bone, but the synthetic HA was mineralized fast in surrounding bone because of it´s higher deposition of calcium.
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