Methods: The four inferior premolar of six beagle dogs were extracted. After a 20 week healing period, 24 implants were inserted. In the following day the implants of the 4th quadrant were placed in function. The implants of the opposite quadrant, used as control, were left free of loading. Animal euthanasia was carried out in three phases: 9, 17 and 31 days after the load application. A radiographic and histological analysis of the bone-implant interface was carried out to understand the dynamics of bone restructuring.
Results: The radiographical results obtained during implant insertion, in the step of application of fixed bridges and before euthanasia for all implants did not show marginal bone resorption at the level of the bone crest, from implant application until the end of the experiment and the kind of load on the implants does not seem to have influenced the behaviour of the marginal bone remodelling. No significant changes were observed between immediate load and control, although there seems to be higher activity in the primary bone formation process close to the interface of implants placed under immediate load. Same differences were found between the vestibular and lingual sides, with a higher amount of bone tissue contacting the vestibular implant side. In both groups there was not observed encapsulated fibrosis. Bone-implant contact showed a slight percentage increase in the implants under immediate load (52,13%) as compared to control (47,6%).
Conclusions: All implants were osteointegrated, since all of them remained clinically stable until euthanasia. Histologically it was verified that there was osteogenic activity at their interface. Immediate load did not affect the implant osteointegration (Study performed at UICOB, FCT R&D unit 4062).