Immediately loaded platform-switched implants in the anterior mandible with fixed prostheses: a randomized, split-mouth, masked prospective trial.

BACKGROUND: Platform-switched implants have been demonstrated to maintain marginal bone-level stability after immediate loading. The present study evaluated crestal bone loss and soft tissue stability around ANKYLOS plus(R) implants (A-implants) and Certain(R) PREVAIL(TM) (B-implants). MATERIALS AND METHODS: Patients were identified to receive three A- or three B-implants on each side of their mandibles, with randomization. All implants were loaded immediately after their insertion and splinted with a cemented provisional prosthesis. Final prostheses were delivered 3 months after implantation. Peri-implant crestal bone loss, gingival recession, and other soft tissue changes were evaluated throughout a 2-year follow-up. RESULTS: A total of one hundred seven implants were placed in 18 patients. Two of the group A-implants and one group B-implant failed. At the final 24-month assessment, bone loss of at least 2 mm (mesially or distally) was recorded at 5 of the 44 surviving A-implants (11%) and 33 of the 47 B-implants (70%), a success rate of 88.63% for the A- and 29.78% for the B-implants. CONCLUSIONS: Significant changes in the level of the crestal bone loss around immediately loaded platform-switched dental implants seem to be related to the platform shape and size, as well as the implant-abutment connection, when abutments are not removed.