The purpose of this study was to observe morphologically new bone formation around PLGA/HA blocks were implanted in hole(5.5mm diameter, 4mm depth) of rabbit´s tibia. At 8th, 14th, 18th weeks, bones with PLGA/HA block implantation 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 ㎛, examined with light(LM) and polarizing microscope(PM). For reflection electron microscope(REM), the resin sections were coated with carbon. The obtained results were as follows.
1. In toluidin blue staining(TBS) of 8th weeks in both groups, there was not restored in bone loss, and new bone formation between resorbed HAs. In PM, compact bone were deep brown while new bones in bone loss showed blue mixed with yellow color, while new bone of experimental group(ExG) showed blue or yellow color. In REM compact bone were light grey while generally dark grey color outside new bone, while new bone around HA of ExG had larger lacunae.
2. In TBS of 14th weeks in control group(CG), there was new bone formation with irregular arranged osteocytes and less number of Harversian canals. In PM of CG, the peripheral compact bone was brown, while new bone in the central area of bone loss showed blue color while ExG showed yellow or darker yellow color. In REM of CG, thicker new bone with Harversian canals showed dark grey color, while wee calcified new bone was connected with less calcified bone in ExG.
3. In TBS of 18th weeks in CG, the bone loss was not completely restored but new bone with irregular arranged osteocytes in both group was seen. In PM of CG, new bone in the central area of bone loss showed still blue color, while new bone in bone loss area of ExG showed almost yellow color. In REM of CG, resorbed HA was surrounded by new bone trabeculae, in EXG, almost implant materials were resorbed in bone loss area and calcification of new bone trabeculae were similar to that of compact bone.
From the aboving results, HAs of both group were almost resorbed at 18 weeks. In control group new bone in the central area, of bone loss showed less calcification and lacuna development, while in experimental group it was similar to that of compact bone but it was less thicker at 18th weeks.
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