Long-term evaluation of immediately loaded implants in the edentulous mandible using fixed bridges and platform shifting.

BACKGROUND: The immediate loading concept has been extensively documented in the anterior part of the mandible when six primary stable implants are placed, splinted with a fixed prosthesis. PURPOSE: The aim of this study was to evaluate the long-term success of immediately occlusal loaded implants with a progressive thread design and platform shifting in the edentulous mandible. MATERIALS AND METHODS: Seventy-eight implants placed in 13 patients and were connected with their abutments immediately after surgery. The implants were splinted using a fixed temporary restoration having occlusal contacts in the centric and group function in the lateral movements of the mandible (immediate occlusal loading). The patients were advised to use soft/liquid diet for the first 6 to 8 weeks of healing in order to reduce excessive loading in the bone-to-implant interface. Abutment level impressions were taken without removing the abutments in order to fabricate the final prostheses. The final restorations were delivered 4 to 8 weeks after surgery and cemented temporarily in order to evaluate the peri-implant soft tissue condition at the different time intervals after removal of the restoration. Clinical stability and radiological indices were evaluated at the start of loading, at 3-month interval after loading, and then annually. RESULTS: After a mean loading period of 75.29 (+/- 38.18) months, no implant was lost (100% success rate). All clinical indices had values in normal levels. The Periotest values demonstrated a continuous reduction, representing high stability. The crestal bone level was relatively stable and only minimal crestal bone loss was observed in some implants. CONCLUSIONS: Long-term success and stability of the peri-implant tissues around immediately loaded mandibular implants are expected when implants with platform shifting are restored with bridges without abutment removal.