Comparison of Brånemark fixture integration and short-term survival using one-stage or two-stage surgery in completely and partially edentulous mandibles

The aim of this prospective study was to compare the clinical integration and survival of Branemark fixtures when using the conventional 2-stage surgical procedure to a 1-stage surgical approach in completely and partially edentulous mandibles. A total of 85 patients were consecutively treated for partial (n=35) or complete (n=50) mandibular edentulousness. Fixtures removed because of mobility, pain or infection were counted as failures. The first 10 patients of each group were selected for radiographical analysis of crestal bone changes 1 year after prosthesis insertion. In 33 patients with edentulous mandibles, 170 fixtures were placed in a 1-stage approach. In this group, 4 fixtures (2.4%) were lost prior to prosthetic restoration. Seventeen edentulous patients received a total of 70 fixtures in a 2-stage procedure. Out of these, 5 fixtures (7.1%) were lost at abutment connection. In 17 partially edentulous patients, 41 fixtures were inserted in a 1-stage approach. Two fixtures (5%) were lost in this group. Finally, 18 partially edentulous patients received a total of 49 fixtures in a 2-stage procedure. Out of these, 6 fixtures (12%) were lost at abutment connection. In total 313 of the 330 installed mandibular implants were loaded between 6 and 12 months (94.8% success). No further losses occurred in the implants functioning at least 1 year (267 implants) or at least 2 years (59 implants). Statistical analysis (Chi square test) revealed no difference in fixture survival between the treatment modalities, Radiographical analysis after 1 year of functional loading showed the typical bone resorption changes up to the most coronal implant thread in both modalities. Although this study pertains to relatively early loading of 2 years, the results seem to indicate that in the mandible a 1-stage surgical approach with Branemark fixtures may be as predictable as the conventional 2-stage procedure