ABSTRACT
<p><b>OBJECTIVE</b>To investigate the effect of implant superstructure with platform switching to the osseointegration of implant-bone interface in immediate loading.</p><p><b>METHODS</b>The bilateral mandiblular fourth premolars of 5 beagle dogs were extracted, and 3 months later, 10 implants were implanted and the abutments were accessed immediately to form immediate loading. Using self-control, the abutment with platform switching was used in the experimental side, and the traditional abutment used in the control side. The experimental animals were sacrificed after 3 months, and non-decalcified implant-bone sections were made.</p><p><b>RESULTS</b>A favorable osseointegration of implant-bone interface in 4 animals (8 implants) was observed except for one failed case. A large number of osteoblasts and different mineralized bone were observed. In experimental side, the bone and implant-neck were nearly in the same level, but the bone around the implant-neck was significantly absorbed in control side.</p><p><b>CONCLUSIONS</b>Using different superstructure in immediate loading could affect the osseointegration of implant-neck. The platform switching technology is conducive to the keeping of implant-neck bone.</p>