Immediate Loading of Brånemark System TiUnite and Machined-Surface Implants in the Posterior Mandible, Part II: A Randomized Open-Ended 9-Year Follow-up Clinical Trial

Purpose: To present clinical results with 9 years of follow-up of a protocol of immediately loaded implants with two different surfaces. Materials and Methods: A total of 44 patients received 66 Brånemark System TiUnite and 55 Brånemark machined implants, all immediately loaded. Control examinations were performed on the day of surgery and at 1-, 3-, and 9-year follow-up visits. Results: All implant sites had intact buccal and lingual bone walls. The prefabricated provisional restorations showed an excellent fit. Three TiUnite and 8 machined implants failed within 7 weeks of loading, resulting in a cumulative survival rate of 95.5% and 85.5% respectively after 9 years of load. The survival rate for implants in a partial prosthesis was 98.8% and 92.2% for single restorations in the TiUnite group, and 87.8% and 83.2%, respectively, for partial and single resorations in the control group. The marginal bone resorption in the first year was on average 0.9 mm in the TiUnite group and 1.0 mm in the machined group; at the third year it was 0.4 and 0.5 mm, respectively. On examination at 9 years, there was a general settlement of the bone, with a negligible further loss in height. Conclusions: The unchanged survival rate and the low bone loss after 9 years confirm the feasibility of an immediate loading protocol in the mandible, which included flapless surgery. TiUnite implants obtained a 10% higher success rate compared with machined fixtures.