Early loading of four or five Astra Tech fixtures with a fixed cross-arch restoration in the mandible

BACKGROUND: A change in implant placement has emerged recently from two-stage to one-stage surgery and to earlier and even immediate loading of the fixtures. PURPOSE: The aim of this study was to verify whether four or five fixtures installed in the edentulous mandible were suitable for early loading with a cross-arch fixed restoration. MATERIALS AND METHODS: In 25 consecutively treated patients (28-88 yr), four or five Astra Tech fixtures (Mölndal, Sweden) were installed in edentulous mandibles. During the same surgical procedure, the abutments were connected. An impression was taken immediately after surgery. All patients received a fixed prosthetic rehabilitation of 10 to 12 teeth made of a cast metal framework and acrylic teeth/gingiva within a month. The fixtures were followed up clinically and radiographically for 7 to 24 months. Bone level was measured from the most coronal point of the vertical part of the fixture to the most apical bone level mesially or distally. RESULTS: No fixtures were lost during follow-up. No postoperative complications occurred. Radiographic analysis showed a mean bone level of 0.6 mm after 7 to 12 months. Fixtures followed up from 13 to 18 and 19 to 24 months showed a mean bone level of 0.7 mm. Around two fixtures, the bone level was found at the first implant thread. All other fixtures showed the bone level somewhere along the vertical unthreaded part of the fixture. CONCLUSIONS: Early loading within 1 month of four or five Astra Tech fixtures in the edentulous mandible is a predictable procedure for a follow-up period of 6 to 24 months.