The purpose of this study was to observe the early osseointegration adjacent to hydroxyapatite coated IMZ implant in rabbit tibia. Sacrification the 3rd day, 1st, 2nd, 4t, 8th week after implantation, taken specimens were fixed in 10% neutral formalin solution, dehydrated and embedded in Spurr low viscosity resin. These resin blocks were cut 500㎛ in thickness in the and grinded up to 100㎛. These were examined under polarizing microscope and reflection electron microscope for osseointegration and bone density. The obtained results were as follows.
1. Polarizing microscopic findings 3 days after implantation showed soft tissue as red color, weekly new bone formation as blue color adjacent to the surface of implant. Reflection electron microscopic features showed implant as white color, HA as light gray and soft tissue as black in central hole.
2. Polarizing microscopic findings on the 1st week after implantation showed calcified new bone formation around the surface of implant, and new bone formation as blue color arising from old bone was partially attached with implant. Reflection electron microscopic features showed new bone containing larger lacuna attached to implant as dark gray color.
3. Polarizing microscopic findings on the 2nd week after implantation showed concentric new bone formation around the surface of implant. Reflection electron microscopic features showed new bone partially attached to implant and new bone formation as dark gray color in central hole.
4. Polarizing microscopic findings on the 4th week after implantation showed new bone formation as blue color adjacent to the surface of implant in central hole. Osteocytes of bone with different calcification around implant was different orientation to old bone. Reflection electron microscopic features showed new bone as gray color growing toward central hole and proximal bone as dark gray color. Generally trabecular bone attached to HA coated implant was darker gray than old bone.
5. Polarizing microscopic findings on the 8th week after implantation showed bone containing irregular orientation of osteocytes attached to HA coated implant, and unilateral trabecular bone showed less different calcification from old bone. Similar orientation of osteocytes of trabecular bone to old bone was found, but calcification was different. Reflection electron microscopic features showed new bone as gray color growing to central hole. Density of trabecular bone attached to the implant was similar to old bone.
From above results, bone particles were resorbed on 2nd week, new bone formation on 3rd day, calcification adjacent to the surface of implant in central hole, and from the 4th week new bone formation was growing into central hole. On the 8th week new bone showed mostly osseointegration in the surface of implant and similar calcification to old bone in other portions.
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