The purpose of this study was to observe morphologically the effect of low irradiation dosage on early bone formation in the hole of IMZ implant after implantation, to measure AZ labelled bone width, attached bone to surface of implant, and PCNA index, and to examine bone density by reflaction microscope. After IMZ implants were embedded into rabbit tibia and irradiftied, Alizarin red was injected before 3 days of sacrification. At 1, 2, 4, 8 weeks after irradiation, HA coated IMZ imPlants associated with bone tissue were fixed with 10% neutral formalin, dehydrated, and embedded with Spurr low viscosity. After the specimen was cut by 500㎚ with slow, diamond wheel saw, these were grinded up to 1OO㎚ with grinder, which was examined with light microscope and fluorescent microscope and reflection microscope. The obtained results were as follows.
1. From 1 to 2 weeks of control group trabecular bone from old bone was associated with new bone around implant. In experimeatal group bone formation in hole and new trabecular bone old bone, partially surrunding implant, run into inner side. Both of them showed the highest of PCNA index and increased AZ-labelled bone width.
2. On 4 weeks of control group new trabecular bone, partially surrunding implant, run into inner side of hole. In experimental group trabecular bone in inner side was seen. There was the largest width of AZ-labelled bone but PCNA index was decreased.
3. On 8 weeks of control group new trabecular bone with irregular arrangement of osteocytes, surrounding inlplant run toward central portion. In experimental group new trabecular bone completely surrounding implant, run into central portion. Proportion of attached bone to IMZ implant was the highest but AZ-labelled bone width and PCNA index was decreased.
From above results, in experimental group irradiation had an effect on neow bone formation by increased PCNA index on 2 weeks and AZ-labelled bone width on 4 weeks, but there was no change of bone to implant rartio and bone density.
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