| Objective Through the establishment of animal model of immediate loading implant with different superstructures, this research observed the periapical X ray films, and analyzed the change of implant marginal bone when different superstructures are applied in immediate-loading implant. The ground section of implant-bone tissue was observed in order to study the effect on healing, mineralization and remodeling of the interface bone when platform switching technique was applied in superstructure.Methods The bilateral mandible 4th premolar (PM4) of 5 beagle dogs was extracted. The implant surgery was operated after 3 months healing period. Left and right side of each animal mandible were implanted one titanium cylindrical screw threaded implant respectively. The implant superstructure was installed after implant surgery immediately in order to ensure immediate loading. Self-controlled design was applied in experiment. The platform-switched abutment was used in experimental side, and the butt-joint abutment in control one. The periapical X-ray film was obtained the day after surgery and 3 months later. The distal and mesial marginal bone loss of implant was measured on the films, and non-decalcified implant-bone ground section was produced and observed.Results Periapical X ray films shows,4 animals had got successful immediate loading, and the implant screw integrated with bone tissues tightly. But there is different radiolucency at the bone of implant-margin. To measure implant-marginal bone loss, the results show that the mean of mesial and distal implant marginal bone loss were 0.41mm and 0.15mm at experimental side, and 1.44mm and 1.42mm at control side.The ground sections of successful immediate-loading show there are a large number of osteoblasts and bone tissue during different mineralized level at implant-tissue interface, which indicates a fine osteointegration. Obvious bone loss can be observed on the neck of implants in control side. Both the neck of implant and abutment in control side are surrounded by fibrous connective tissue. There is not obvious bone absorption in experimental side, and the bone level is almost equal with the neck of implant, even more highly than that.Conclusion It will not hinder the osseointegration of implant-tissue interface. It will prevent the absorption of implant marginal bone effectively when platform switching technique was employed in immediate-loading implant, which can benefit the preservation of alveolar bone around implants. |
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