Bone Level Changes Around Axial and Tilted Implants in Full-Arch Fixed Immediate Restorations. Interim Results of a Prospective Study

Purpose: The aim of this prospective study was to assess clinical outcomes and peri-implant bone level changes around tilted and axial implants supporting full-arch fixed immediate rehabilitations up to 60months of loading. Material and Methods: Forty-seven patients (22 women and 25 men) were included in the study. Each patient received a full-arch fixed bridge supported by two axial and two distal tilted implants. Loading was applied within 48hours of surgery. Patients were scheduled for follow-up at 6, 12, 18, 24months, and annually up to 5years. At each follow-up, plaque level and bleeding scores were assessed and radiographic evaluation of marginal bone level change was performed. Periapical radiographs were taken using a paralleling technique, and subsequently scanned at 600dpi. An image analysis software was used to assess bone level. Results: A total of 33 mandibles and 16 maxillae were rehabilitated (two patients received a fixed prosthesis in both arches). One hundred ninety-six Nobel Biocare implants of 4mm diameter were placed. The mean follow-up duration was 52.8months (range 30-66months) in the mandible, and 33.8months (range 22-40 months) in the maxilla. All subjects attended the scheduled follow-up visits. No implant was lost. No significant difference in marginal bone loss was found between axial and tilted implants in both jaws, at each follow-up. No significant difference in bone loss was found between mandible and maxilla, for both axial and tilted implants at each comparable time frame, although slightly higher mean values were always found for the mandible. Conclusion: The use of tilted implants in the immediate rehabilitation of fully edentulous jaws is safe and is not associated to a higher marginal bone loss as compared to axially placed implants.