성견 하악골에 단독형으로 식립된 즉시부하 인공치아의 골 유합

The purpose of this study was to investigate whether immediately loaded freestanding implants without splinting were successful. For this study, the bone to implant interface was investigated using histomorphometric analysis and histologic observation of the implants in canine lower jaw. Implants were divided into two different groups according to the occlusal force transmission procedures: 1) multiunited implants stabilized by a fixed provisional prosthesis, and 2) freestanding implants loaded individually without stabilization, immediately after placement in the edentulous canine lower jaw. The observation and measurement of specimens were performed at 2,4, 8, and 12 weeks after implant placement. Histomorphometric results were analyzed statistically using a t-test. In the histologic findings, there was no significant difference between multiunited and freestanding implants. Immediately loaded implants were successfully osseointegrated irrespective of the existence of splinting. Bone tissue was found to be in close approximation to the titanium implant surface without fibrous connective tissue formation, inflamatory infiltration, or infrabony pocket formation. The histomorphometric analysis showed that the mean implant to bone contact ratios of multiunited and freestanding implants were 70.86% and 73.11% in 2-weeks after implant placement, respectively. The mean percentages are as follows: 67.11% and 61.87% at 4-week, 64.99% and 74.30% at 8-week, and 70.87% and 66.67% at 12-week, respectively. The mean bone area ratios in comparison with the threaded area were 86.02% and 84.26% at 2-weeks, 84.47% and 81.21% at 4-weeks, 86.72% and 86.80% at 8-weeks, and 87.34% and 82.52% at 12-weeks for multiunited and freestanding implants, respectively. No statistically significant difference in the bone contact ratio between multiunited and freestanding implants was found at any periods of time(P<0.05%). In the bone area ratio, there was no significant difference between the two groups at 2，4, and 8th week, respectively, except 12th week. It was concluded that the splinting procedure could not be the exclusive factor determining the success of osseointegration of the immediately loaded implants.